ALBERT

All Library Books, journals and Electronic Records Telegrafenberg

Your email was sent successfully. Check your inbox.

An error occurred while sending the email. Please try again.

Proceed reservation?

Export
Filter
  • Articles  (775)
  • Oxford University Press  (775)
  • American Association for the Advancement of Science (AAAS)
  • American Chemical Society (ACS)
  • American Geophysical Union (AGU)
  • 2015-2019  (775)
  • 2016  (775)
  • Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition  (775)
Collection
  • Articles  (775)
Publisher
Years
  • 2015-2019  (775)
Year
Journal
  • 1
    Publication Date: 2016-08-03
    Description: We employed the warm temperate conifer Cunninghamia lanceolata (Lamb.) Hook. as a model of plantation forest species to investigate ecophysiological responses to root treatments (control (0%), and ~25, 50 or 75% of the initial root mass) under well-watered and water-limited conditions. Our results indicated that total root dry mass accumulation was negatively associated with the severity of root pruning, but there was evidence of multiple compensatory responses. The plants exhibited higher instantaneous and long-term (assessed by carbon isotope composition, 13 C) water-use efficiency in pruning treatments, especially under low water availability. Root pruning also increased the fine root/total root mass ratio, specific root length and fine root vitality in both water availability treatments. As a result of the compensatory responses, under well-watered conditions, height, stem dry mass accumulation, leaf/fine root biomass ratio (L/FR), transpiration rate, photosynthetic capacity and photosynthetic nitrogen-use efficiency ( E N ) were the highest under 25% pruning. Yet, all these traits except L/FR and foliage nitrogen content were severely reduced under 75% pruning. Drought negatively affected growth and leaf gas exchange rates, and there was a greater negative effect on growth, water potential, gas exchange and E N when 〉25% of total root biomass was removed. The stem/aboveground mass ratio was the highest under 25% pruning in both watering conditions. These results indicate that the responses to root severance are related to the excision intensity and soil moisture content. A moderate root pruning proved to be an effective means to improve stem dry mass accumulation.
    Print ISSN: 0829-318X
    Electronic ISSN: 1758-4469
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 2
    Publication Date: 2016-08-03
    Description: The timing of wood formation is crucial to determine how environmental factors affect tree growth. The long-lived bristlecone pine ( Pinus longaeva D. K. Bailey) is a foundation treeline species in the Great Basin of North America reaching stem ages of about 5000 years. We investigated stem cambial phenology and radial size variability to quantify the relative influence of environmental variables on bristlecone pine growth. Repeated cellular measurements and half-hourly dendrometer records were obtained during 2013 and 2014 for two high-elevation stands included in the Nevada Climate-ecohydrological Assessment Network. Daily time series of stem radial variations showed rehydration and expansion starting in late April–early May, prior to the onset of wood formation at breast height. Formation of new xylem started in June and lasted until mid-September. There were no differences in phenological timing between the two stands, or in the air and soil temperature thresholds for the onset of xylogenesis. A multiple logistic regression model highlighted a separate effect of air and soil temperature on xylogenesis, the relevance of which was modulated by the interaction with vapor pressure and soil water content. While air temperature plays a key role in cambial resumption after winter dormancy, soil thermal conditions coupled with snowpack dynamics also influence the onset of wood formation by regulating plant–soil water exchanges. Our results help build a physiological understanding of climate–growth relationships in P. longaeva , the importance of which for dendroclimatic reconstructions can hardly be overstated. In addition, environmental drivers of xylogenesis at the treeline ecotone, by controlling the growth of dominant species, ultimately determine ecosystem responses to climatic change.
    Print ISSN: 0829-318X
    Electronic ISSN: 1758-4469
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 3
    Publication Date: 2016-08-03
    Description: Seasonal analyses of cambial cell production and day-by-day stem radial increment can help to elucidate how climate modulates wood formation in conifers. Intra-annual dynamics of wood formation were determined with microcores and dendrometers and related to climatic signals in Norway spruce ( Picea abies (L.) Karst.). The seasonal dynamics of these processes were observed at two sites of different altitude, Savignano (650 m a.s.l.) and Lavazè (1800 m a.s.l.) in the Italian Alps. Seasonal dynamics of cambial activity were found to be site specific, indicating that the phenology of cambial cell production is highly variable and plastic with altitude. There was a site-specific trend in the number of cells in the wall thickening phase, with the maximum cell production in early July (DOY 186) at Savignano and in mid-July (DOY 200) at Lavazè. The formation of mature cells showed similar trends at the two sites, although different numbers of cells and timing of cell differentiation were visible in the model shapes; at the end of ring formation in 2010, the number of cells was four times higher at Savignano (106.5 cells) than at Lavazè (26.5 cells). At low altitudes, microcores and dendrometers described the radial growth patterns comparably, though the dendrometer function underlined the higher upper asymptote of maximum growth in comparison with the cell production function. In contrast, at high altitude, these functions exhibited different trends. The best model was obtained by fitting functions of the Gompertz model to the experimental data. By combining radial growth and cambial activity indices we defined a model system able to synchronize these processes. Processes of adaptation of the pattern of xylogenesis occurred, enabling P. abies to occupy sites with contrasting climatic conditions. The use of daily climatic variables in combination with plant functional traits obtained by sensors and/or destructive sampling could provide a suitable tool to better investigate the effect of disturbances on response strategies in trees and, consequently, contribute to improving our prediction of tree growth and species resilience based on climate scenarios.
    Print ISSN: 0829-318X
    Electronic ISSN: 1758-4469
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 4
    Publication Date: 2016-08-03
    Description: In deciduous trees growing in temperate forests, bud break and growth in spring must rely on intrinsic carbon (C) reserves. Yet it is unclear whether growth and C storage occur simultaneously, and whether starch C in branches is sufficient for refoliation. To test in situ the relationships between growth, phenology and C utilization, we monitored stem growth, leaf phenology and stem and branch nonstructural carbohydrate (NSC) dynamics in three deciduous species: Carpinus betulus L., Fagus sylvatica L. and Quercus petraea (Matt.) Liebl. To quantify the role of NSC in C investment into growth, a C balance approach was applied. Across the three species, 〉95% of branchlet starch was consumed during bud break, confirming the importance of C reserves for refoliation in spring. The C balance calculation showed that 90% of the C investment in foliage (7.0–10.5 kg tree –1 and 5–17 times the C needed for annual stem growth) was explained by simultaneous branchlet starch degradation. Carbon reserves were recovered sooner than expected, after leaf expansion, in parallel with stem growth. Carpinus had earlier leaf phenology (by ~25 days) but delayed cambial growth (by ~15 days) than Fagus and Quercus , the result of a competitive strategy to flush early, while having lower NSC levels.
    Print ISSN: 0829-318X
    Electronic ISSN: 1758-4469
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 5
    Publication Date: 2016-08-03
    Description: Fungal infections result in decreases in photosynthesis, induction of stress and signaling volatile emissions and reductions in constitutive volatile emissions, but the way different physiological processes scale with the severity of infection is poorly known. We studied the effects of infection by the obligate biotrophic fungal pathogen Melampsora larici-populina Kleb., the causal agent of poplar leaf rust disease, on photosynthetic characteristics, and constitutive isoprene and induced volatile emissions in leaves of Populus balsamifera var. suaveolens (Fisch.) Loudon. exhibiting different degrees of damage. The degree of fungal damage, quantified by the total area of chlorotic and necrotic leaf areas, varied between 0 (noninfected control) and ~60%. The rates of all physiological processes scaled quantitatively with the degree of visual damage, but the scaling with damage severity was weaker for photosynthetic characteristics than for constitutive and induced volatile release. Over the whole range of damage severity, the net assimilation rate per area ( A A ) decreased 1.5-fold, dry mass per unit area 2.4-fold and constitutive isoprene emissions 5-fold, while stomatal conductance increased 1.9-fold and dark respiration rate 1.6-fold. The emissions of key stress and signaling volatiles (methanol, green leaf volatiles, monoterpenes, sesquiterpenes and methyl salicylate) were in most cases nondetectable in noninfested leaves, and increased strongly with increasing the spread of infection. The moderate reduction in A A resulted from the loss of photosynthetically active biomass, but the reduction in constitutive isoprene emissions and the increase in induced volatile emissions primarily reflected changes in the activities of corresponding biochemical pathways. Although all physiological alterations in fungal-infected leaves occurred in a stress severity-dependent manner, modifications in primary and secondary metabolic pathways scaled differently due to contrasting operational mechanisms.
    Print ISSN: 0829-318X
    Electronic ISSN: 1758-4469
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 6
    Publication Date: 2016-08-03
    Description: Current knowledge of the genetic mechanisms underlying the inheritance of photosynthetic activity in forest trees is generally limited, yet it is essential both for various practical forestry purposes and for better understanding of broader evolutionary mechanisms. In this study, we investigated genetic variation underlying selected chlorophyll a fluorescence (ChlF) parameters in structured populations of Scots pine ( Pinus sylvestris L.) grown on two sites under non-stress conditions. These parameters were derived from the OJIP part of the ChlF kinetics curve and characterize individual parts of primary photosynthetic processes associated, for example, with the exciton trapping by light-harvesting antennae, energy utilization in photosystem II (PSII) reaction centers (RCs) and its transfer further down the photosynthetic electron-transport chain. An additive relationship matrix was estimated based on pedigree reconstruction, utilizing a set of highly polymorphic single sequence repeat markers. Variance decomposition was conducted using the animal genetic evaluation mixed-linear model. The majority of ChlF parameters in the analyzed pine populations showed significant additive genetic variation. Statistically significant heritability estimates were obtained for most ChlF indices, with the exception of DI 0 /RC, D0 and P0 ( F v / F m ) parameters. Estimated heritabilities varied around the value of 0.15 with the maximal value of 0.23 in the ET 0 /RC parameter, which indicates electron-transport flux from Q A to Q B per PSII RC. No significant correlation was found between these indices and selected growth traits. Moreover, no genotype  x  environment interaction (G  x  E) was detected, i.e., no differences in genotypes’ performance between sites. The absence of significant G  x  E in our study is interesting, given the relatively low heritability found for the majority of parameters analyzed. Therefore, we infer that polygenic variability of these indices is selectively neutral.
    Print ISSN: 0829-318X
    Electronic ISSN: 1758-4469
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 7
    Publication Date: 2016-08-03
    Description: The ethylene response factor (ERF) family is one of the largest plant-specific transcription factor families, playing an important role in plant development and response to stresses. The ERF76 gene is a member of the poplar ERF transcription factor gene family. First, we validated that the ERF76 gene expressed in leaf and root tissues is responsive to salinity stress. We then successfully cloned the ERF76 cDNA fragment containing an open reading frame from di-haploid Populus simonii   x   Populus nigra and proved that ERF76 protein is targeted to the nucleus. Finally, we transferred the gene into the same poplar clone by the Agrobacterium -mediated leaf disc method. Using both RNA-Seq and reverse transcription-quantitative polymerase chain reaction, we validated that expression level of ERF76 is significantly higher in transgenic plants than that in the nontransgenic control. Using RNA-Seq data, we have identified 375 genes that are differentially expressed between the transgenic plants and the control under salt treatment. Among the differentially expressed genes, 16 are transcription factor genes and 45 are stress-related genes, both of which are upregulated significantly in transgenic plants, compared with the control. Under salt stress, the transgenic plants showed significant increases in plant height, root length, fresh weight, and abscisic acid (ABA) and gibberellin (GA) concentration compared with the control, suggesting that overexpression of ERF76 in transgenic poplar upregulated the expression of stress-related genes and increased the ability of ABA and GA biosynthesis, which resulted in stronger tolerance to salt stress.
    Print ISSN: 0829-318X
    Electronic ISSN: 1758-4469
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 8
    Publication Date: 2016-08-03
    Description: Summer droughts are likely to increase in frequency and intensity across Europe, yet long-lived trees may have a limited ability to tolerate drought. It is therefore critical that we improve our understanding of phenotypic plasticity to drought in natural populations for ecologically and economically important trees such as Populus nigra L. A common garden experiment was conducted using ~500 wild P. nigra trees, collected from 11 river populations across Europe. Phenotypic variation was found across the collection, with southern genotypes from Spain and France characterized by small leaves and limited biomass production. To examine the relationship between phenotypic variation and drought tolerance, six genotypes with contrasting leaf morphologies were subjected to a water deficit experiment. ‘North eastern’ genotypes were collected at wet sites and responded to water deficit with reduced biomass growth, slow stomatal closure and reduced water use efficiency (WUE) assessed by 13 C. In contrast, ‘southern’ genotypes originating from arid sites showed rapid stomatal closure, improved WUE and limited leaf loss. Transcriptome analyses of a genotype from Spain (Sp2, originating from an arid site) and another from northern Italy (Ita, originating from a wet site) revealed dramatic differences in gene expression response to water deficit. Transcripts controlling leaf development and stomatal patterning, including SPCH , ANT , ER , AS1 , AS2 , PHB , CLV1 , ERL1–3 and TMM , were down-regulated in Ita but not in Sp2 in response to drought.
    Print ISSN: 0829-318X
    Electronic ISSN: 1758-4469
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 9
    Publication Date: 2016-08-03
    Description: Isoprene is the most abundant type of nonmethane, biogenic volatile organic compound in the atmosphere, and it is produced mainly by terrestrial plants. The tropical tree species Ficus septica Burm. F. (Rosales: Moraceae) has been shown to cease isoprene emissions when exposed to temperatures of 12 °C or lower and to re-induce isoprene synthesis upon subsequent exposure to temperatures of 30 °C or higher for 24 h. To elucidate the regulation of genes underlying the disabling and then induction of isoprene emission during acclimatization to ambient temperature, we conducted gene expression analyses of F. septica plants under changing temperature using quantitative real-time polymerase chain reaction and western blotting. Transcription levels were analyzed for 17 genes that are involved in metabolic pathways potentially associated with isoprene biosynthesis, including isoprene synthase ( ispS ). The protein levels of ispS were also measured. Changes in transcription and protein levels of the ispS gene, but not in the other assessed genes, showed identical temporal patterns to isoprene emission capacity under the changing temperature regime. The ispS protein levels strongly and positively correlated with isoprene emission capacity ( R 2  = 0.92). These results suggest that transcriptional regulation of ispS gave rise to the temporal variation in isoprene emission capacity in response to changing temperature.
    Print ISSN: 0829-318X
    Electronic ISSN: 1758-4469
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 10
    Publication Date: 2016-08-03
    Description: Clonal integration between ramets can be an ecological advantage of clonal plant species in environments where resources are patchily distributed. We investigated physiological integration among Populus balsamifera L. ramets under drought stress in order to demonstrate water sharing between connected ramets. Pairs of connected ramets were grown in separate pots in the greenhouse where half of ramets had the parental root connection severed and half were left intact. Drought stress was applied to one ramet, and growth, specific leaf area (SLA), net photosynthesis, stomatal conductance, leaf water potential and carbon isotopic composition ( 13 C) were measured after an 8-week growing period. Droughted ramets connected to watered ramets were able to maintain high gas exchange activity and water potential, similar to watered ramets. Leaf water potential and SLA results showed that the root connection was more beneficial for proximal compared with distal ramets. The parental root connection also allowed droughted ramets to discriminate more against 13 C compared with severed ramets. In conclusion, this study shows compelling evidence of physiological integration of connected P. balsamifera ramets through water sharing.
    Print ISSN: 0829-318X
    Electronic ISSN: 1758-4469
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 11
    Publication Date: 2016-07-09
    Description: There is an increasing perception among policy makers that food stamp benefits contribute positively to adult obesity rates. We show that these results are heavily dependent on one’s assumptions regarding the accuracy of reported food stamp participation. When allowing for misreporting, we find no evidence that Supplemental Nutrition Assistance Program participation significantly increases the probability of being obese or overweight among adults. Our results also highlight the inherent bias and inconsistency of common point estimates when ignoring misreporting, with treatment effects from instrumental variable methods exceeding the nonparametric upper bounds by over 200% in some cases.
    Keywords: C11 - Bayesian Analysis, I10 - General, I38 - Government Policy ; Provision and Effects of Welfare Programs
    Print ISSN: 0002-9092
    Electronic ISSN: 1467-8276
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition , Economics
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 12
    Publication Date: 2016-07-09
    Description: Large rural-urban wage gaps observed in many developing countries are suggestive of barriers to migration that keep potential migrants in rural areas. Using long panel data spanning nearly two decades, I study the extent to which migration rates are constrained by liquidity constraints in rural Tanzania. The analysis begins by quantifying the impact of weather variation on household welfare. The results show how household consumption co-moves with temperature, rendering households vulnerable to local weather events. These temperature-induced income shocks are then found to inhibit long-term migration among men, thus preventing them from tapping into the opportunities brought about by geographical mobility.
    Keywords: O12 - Microeconomic Analyses of Economic Development, O15 - Human Resources ; Human Development ; Income Distribution ; Migration, Q54 - Climate ; Natural Disasters ; Global Warming, R23 - Regional Migration ; Regional Labor Markets ; Population
    Print ISSN: 0002-9092
    Electronic ISSN: 1467-8276
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition , Economics
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 13
    Publication Date: 2016-07-09
    Description: Analysis of nationally representative individual-level panel data from 1980 to 2010 reveals a significant negative trend in the agricultural labor supply from rural Mexico, which is the primary source of hired workers for U.S. farms. These findings offer an explanation for the rise over time in U.S. farm wages. Concomitants of the agricultural transformation, including growth in the non-farm economy, falling birth rates, and an increase in rural education, accelerate the transition of rural Mexicans out of farm work. Higher U.S. farm wages and increased border enforcement slow the transition, but the combined impact of these offsetting variables is relatively small. A diminishing farm labor supply has far-reaching implications for farmers, farm labor organizers, rural communities, and agricultural workers.
    Keywords: J21 - Labor Force and Employment, Size, and Structure, J43 - Agricultural Labor Markets, O15 - Human Resources ; Human Development ; Income Distribution ; Migration, Q12 - Micro Analysis of Farm Firms, Farm Households, and Farm Input Markets
    Print ISSN: 0002-9092
    Electronic ISSN: 1467-8276
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition , Economics
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 14
    Publication Date: 2016-07-09
    Print ISSN: 0002-9092
    Electronic ISSN: 1467-8276
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition , Economics
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 15
    Publication Date: 2016-05-06
    Description: Forests and trees throughout the world are increasingly affected by factors related to global change. Expanding international trade has facilitated invasions of numerous insects and pathogens into new regions. Many of these invasions have caused substantial forest damage, economic impacts and losses of ecosystem goods and services provided by trees. Climate change is already affecting the geographic distribution of host trees and their associated insects and pathogens, with anticipated increases in pest impacts by both native and invasive pests. Although climate change will benefit many forest insects, changes in thermal conditions may disrupt evolved life history traits and cause phenological mismatches. Individually, the threats posed to forest ecosystems by invasive pests and climate change are serious. Although interactions between these two drivers and their outcomes are poorly understood and hence difficult to predict, it is clear that the cumulative impacts on forest ecosystems will be exacerbated. Here we introduce and synthesize the information in this special issue of Forestry with articles that illustrate the impacts of invasions of insects and pathogens, climate change, forest management and their interactions, as well as methods to predict, assess and mitigate these impacts. Most of these contributions were presented at the XXIV IUFRO World Congress in 2014.
    Print ISSN: 0015-752X
    Electronic ISSN: 1464-3626
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 16
    Publication Date: 2016-05-06
    Description: Puccinia psidii is a major threat to members of the Myrtaceae worldwide. New Zealand is still free of P. psidii but possesses significant Eucalyptus plantations as well as valuable native tree species such as Metrosideros excelsa and Leptospermum scoparium that could be at risk in the event of an incursion. As part of preparing for a potential incursion, we generated a barcode reference library for 〉100 diverse species of Myrtaceae occurring in New Zealand by sequencing internal transcribed spacer (ITS), external transcribed spacer (ETS) and maturase K ( matK ), or by obtaining relevant sequences from GenBank. The Myrtaceae DNA barcoding database will enable rapid identification of large numbers of host species in the event of a myrtle rust incursion. We undertook a comparative analysis of the ability for the three mentioned loci to discriminate species. Interspecific divergence was assessed by mean interspecific distance, prime and minimum interspecific distance; intraspecific variation was evaluated by mean intraspecific difference, and coalescent depth. Overall identification efficiency of the three loci sequenced was determined using BLAST1 and Near Distance methods. Barcoding gaps between inter- and intraspecific divergences were also analysed. ITS and ETS share similar mean interspecific distance, prime and minimum interspecific distance values – both higher than obtained for matK . In contrast, in terms of intraspecific variation, matK had higher values than ITS and ETS in all three metrics analysed. ITS had the highest identification success rate for species followed by matK and ETS, respectively, as measured by BLAST1 and Near Distance methods. Overall identification success rate increases when a combination of ITS and matK in particular is used. The sequence data are not only a valuable reference collection for a myrtle rust response but also a national botanical resource.
    Print ISSN: 0015-752X
    Electronic ISSN: 1464-3626
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 17
    Publication Date: 2016-05-06
    Description: Future forests are being shaped by changing climate and disturbances. Climate change is causing large-scale forest declines globally, in addition to distributional shifts of many tree species. Because environmental cues dictate insect seasonality and population success, climate change is also influencing tree-killing bark beetles. The mountain pine beetle, Dendroctonus ponderosae , is a major disturbance in Pinus forests of the western US. Using a mechanistic, phenology-based demographic model driven by downscaled daily temperature data, we describe recent and future spatial and temporal thermal suitability for mountain pine beetle population growth in a topographically complex region. Trends in model-predicted growth rates among Global Climate Models were similar and suggest that, relative to future trends, mountain pine beetle population growth within the past 60 years was most optimal at middle elevations and least optimal at the lowest and highest elevations. This trend aligns with observed mountain pine beetle-caused tree mortality that was greatest at middle elevations between 1997 and 2013, as estimated from Aerial Detection Surveys. However, thermal suitability for optimal phenological synchrony was predicted to shift in recent years, and by the end of the century, the best thermal habitats for mountain pine beetle will be at the lowest and highest elevations. Mechanistic demographic models are valuable tools for modelling future thermal regimes that may be both beneficial and maladaptive for mountain pine beetle population growth and subsequent tree mortality.
    Print ISSN: 0015-752X
    Electronic ISSN: 1464-3626
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 18
    Publication Date: 2016-05-06
    Description: Forest degradation is a major issue for policy-makers that is exacerbated by no clear and globally accepted definition of the term. For forest managers, a loss of forest productive capacity is one form of forest degradation. We present a quantitative method to assess forest degradation from a productivity perspective. Our method uses a standard stocking chart and calculation methods based on standard forest inventory data, to derive a clear threshold value for stocking, below which a forest should be considered degraded. The method is illustrated using the example of a self-regenerating Nothofagus production forest type from Chile. For that forest type, we determined that harvesting trees to below a specific basal area relative to site type, resulted in a loss of resilience, an unpredictable shift in ecosystem state, and a degraded condition. Our method illustrates how over-harvesting can degrade the long-term productivity of a stand and forest resilience. Nevertheless, it is important to consider that forests can also be degraded from other perspectives, such as loss of biodiversity, carbon, or protective functions as a result of excessive disturbances. Ecosystem management requires that managers consider degradation from a range of perspectives. We see the quantified approach used here as a way to provide practitioners with, in part, a transition from sustained yield to ecosystem management with an ultimate objective of providing a pathway towards adaptive management of complex systems and avoiding degradation.
    Print ISSN: 0015-752X
    Electronic ISSN: 1464-3626
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 19
    Publication Date: 2016-05-06
    Description: The Asian longhorned beetle (ALB), Anoplophora glabripennis (Coleoptera: Cerambycidae), is one of the most harmful invasive species in Europe and North America, causing enormous economic damage to broadleaved trees growing in urban parks and gardens. As a quarantine species, everywhere it has been introduced ALB has led to the application of expensive eradication programmes often associated with additional indirect costs due to the loss of ornamental value connected with the presence of trees in urban areas. The aims of this article are to quantify the impact of ALB in terms of tree mortality and their ornamental value during the first year eradication of an infestation in Northern Italy, and to perform an economic assessment of the eradication programme vs inaction. During the first year of eradication 367 ALB infested trees were removed from the infestation area at a total cost of about 48 000, comprising scientific advice (21 per cent), tree survey (38 per cent) and plant removal (41 per cent). The ornamental value of the infested trees was assessed at about 850 per tree. The ALB eradication programme allowed a reduction of 52 per cent of the damage expected in the following year, corresponding to an ornamental value of about 300 000. The ornamental value of the saved trees was ~6 times higher than the costs for their protection.
    Print ISSN: 0015-752X
    Electronic ISSN: 1464-3626
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 20
    facet.materialart.
    Unknown
    Oxford University Press
    Publication Date: 2016-03-31
    Print ISSN: 0002-9092
    Electronic ISSN: 1467-8276
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition , Economics
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 21
    Publication Date: 2016-03-31
    Print ISSN: 0002-9092
    Electronic ISSN: 1467-8276
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition , Economics
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 22
    Publication Date: 2016-03-31
    Description: Thinly traded agricultural commodity markets are a concern for farmers and policy markers due to the belief that prices in these settings will be highly volatile, subject to manipulation, and incapable of efficiently allocating resources. Analysis of thin agricultural markets has to date been impeded by lack of an appropriate analytical framework from which to study their behavior. In this paper we propose the modern agricultural markets (MAM) framework as an appropriate paradigm through which to view and evaluate thin markets. We argue that thinly traded markets that meet key conditions required for a MAM will generate maximum economic surplus and enable farmers to earn at least a competitive return on their investments. In the absence of these conditions, however, the concerns known as the "thin market problem" have validity. We set forth the MAM framework, interpret it in a thin-market context, and conduct several brief case studies of thin markets to illustrate use of the approach and draw some key inferences about these markets' behavior. The analysis indicates that appropriate government policies directed to thin markets are those that facilitate their convergence to MAM status, but in reality key policies under recent consideration would have the opposite effect.
    Keywords: L10 - General, Q13 - Agricultural Markets and Marketing ; Cooperatives ; Agribusiness
    Print ISSN: 0002-9092
    Electronic ISSN: 1467-8276
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition , Economics
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 23
    Publication Date: 2016-08-09
    Description: This article examines the impact of a consumption tax on environmentally unfriendly animal-based foods. It focuses on three dimensions: environmental emissions, diet quality and social equity. Using scanner data, we derive elasticities from an Exact Affine Stone Index demand system and simulate two scenarios, one including and one excluding nutritional concerns. Our results show that an environmental tax may reduce emissions (by –6.6 to –13.2 per cent based on the indicators) and improve diet quality (1.2 per cent) with a modest impact on the food-at-home budget (–4.0 per cent). This beneficial synergy between environmental and nutritional effects holds across income and age groups, with a small regressive impact.
    Print ISSN: 0165-1587
    Electronic ISSN: 1464-3618
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition , Economics
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 24
    Publication Date: 2016-08-09
    Description: In recent years, produce imports to the United States from the southern hemisphere made wintertime consumption common. Focusing on imports of fresh berries – strawberries, blueberries, blackberries and raspberries – this study asks what is the value to consumers of increasing the availability of berries in winter? The study adapts Hausman's new product introduction methods. The largest benefits were associated with initiating trade. Further increases suggest smaller benefits. Among the four berries, consumer benefits of initiating trade are largest for strawberries at $2.5 billion, over twice current expenditures. Further price reductions might generate further benefits of $520 million annually.
    Print ISSN: 0165-1587
    Electronic ISSN: 1464-3618
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition , Economics
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 25
    Publication Date: 2016-08-09
    Description: This article shows that the introduction of a conditional collective bonus in an agri-environmental scheme (AES) can improve farmers' participation and increase land enrolment for lower overall budgetary costs. This monetary bonus is paid in addition to the usual AES payment if a given threshold is reached in terms of aggregate farmer participation. Using a choice experiment, we estimate the preferences of winegrowers in the South of France for such a bonus. We show that it contributes to increased expectations of farmers on others' participation, therefore shifting a pro-environmental social norm and favouring the adoption of less pesticide-intensive farming practices.
    Print ISSN: 0165-1587
    Electronic ISSN: 1464-3618
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition , Economics
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 26
    Publication Date: 2016-08-09
    Description: We develop a general framework in which public goods are conflicting (complementary) if an increase in the provision of one public good raises (lowers) the marginal cost of providing another public good. The framework is used to analyse the policy implications of maintaining safe minimum standards (SMSs) for two public goods. The comparative-static results are illustrated using a sector model for Norwegian agriculture in which the SMSs for food security, agrobiodiversity and greenhouse gas emissions are modelled as constraints. The simulations show that even if public goods are conflicting, better-targeted policies can achieve SMSs at lower social costs.
    Print ISSN: 0165-1587
    Electronic ISSN: 1464-3618
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition , Economics
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 27
    Publication Date: 2016-08-09
    Description: Empirical evidence on household risk balancing behaviour is presented by estimating a fixed effects seemingly unrelated regression model using Swiss Farm Accountancy Data Network data. We find that in response to changes in expected business risks, Swiss farm households not only make strategic farm financial risk decisions (original risk balancing), but also make strategic off-farm decisions (household risk balancing) by altering their share of off-farm income and relative consumption. Small farms appear to make more use of household risk balancing strategies whereas large farms conversely make more use of the original risk balancing strategy.
    Print ISSN: 0165-1587
    Electronic ISSN: 1464-3618
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition , Economics
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 28
    Publication Date: 2016-08-09
    Print ISSN: 0165-1587
    Electronic ISSN: 1464-3618
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition , Economics
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 29
    Publication Date: 2016-08-09
    Description: Empirical studies on farmland rental rates so far have predominantly concentrated on modelling conditional means using spatial autoregressive models. While these models only focus on the central tendency of the response variable, quantile regression provides more detailed insight by modelling different points of the conditional distribution as a function of covariates. Based on data from the German agricultural census, this article contributes to the agricultural economics literature by modelling conditional quantiles of farmland rental rates semi-parametrically using Bayesian geoadditive quantile regression. Our results stress the importance of using semi-parametric regression models, as several covariates influence rental rates in an explicit non-linear way. Moreover, our analysis allows us to uncover potential heterogeneities of the estimated effects across the conditional distribution of rental rates. By explicitly modelling and visually presenting the spatial effects, we also provide additional insight into the spatial structure of German farmland rental rates.
    Print ISSN: 0165-1587
    Electronic ISSN: 1464-3618
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition , Economics
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 30
    Publication Date: 2016-08-20
    Description: Agricultural conservation easements have positive externalities but few studies examine the supply-side. This paper explores whether easements may also overcome a credit-market failure, as banks may not be lending based on the full developed value of land. Original survey data test our research hypotheses and show profitable owners and nonoperators to be using easement payments to extract capital from their land by using the preservation programs as a bank. The results also show that the unprofitable owners and operators are reinvesting in their agricultural enterprises. Both results are consistent with an underlying credit-market failure, and the latter suggests that easements may provide indirect efficiency enhancement. The results suggest an integration of policies on agricultural finance and land preservation might lead to improved efficiency.
    Keywords: Q24 - Land
    Print ISSN: 2040-5790
    Electronic ISSN: 2040-5804
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition , Economics
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 31
    Publication Date: 2016-08-20
    Description: A multi-year drought has taken a severe toll on the agricultural economy of California’s Central Valley. Index insurance is an instrument with the potential to protect water users from economic losses due to periodic water shortages. An index insurance product based on the Sacramento Index and adapted to the Central Valley Project water supply is proposed. To address the potential for intertemporal adverse selection, three product designs are suggested: (1) "early bird" insurance; (2) variable premium insurance; and (3) variable deductible insurance. The performance of the designs are assessed using loss functions from the Westlands Water District in the San Joaquin Valley.
    Keywords: Q14 - Agricultural Finance, Q15 - Land Ownership and Tenure ; Land Reform ; Land Use ; Irrigation, Q54 - Climate ; Natural Disasters ; Global Warming
    Print ISSN: 2040-5790
    Electronic ISSN: 2040-5804
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition , Economics
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 32
    Publication Date: 2016-08-20
    Description: Concerns about the growing prevalence of obesity worldwide have led researchers and policy makers to investigate the potential health impact of fiscal policies such as taxes on unhealthy foods. A common instrument used to measure the relationship between food prices and food consumption is the price elasticity of demand. Using meta-regression analysis we assessed how differences in methodological approaches to estimating demand affected food price elasticities. Most methodological differences had a statistically significant impact on elasticity estimates, which stresses the importance of using meta-estimates or testing the sensitivity of simulation outcomes to a range of elasticity parameters before drawing policy conclusions.
    Keywords: D11 - Consumer Economics: Theory, H31 - Household, Q18 - Agricultural Policy ; Food Policy
    Print ISSN: 2040-5790
    Electronic ISSN: 2040-5804
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition , Economics
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 33
    Publication Date: 2016-08-27
    Description: Taiwan incense-cedar ( Calocedrus formosana (Florin) Florin) and taiwania ( Taiwania cryptomerioides Hayata) are coniferous species growing in Taiwan, Republic of China. Both species are red listed, and hence, their management and conservation are important. The objective of this research was to determine the effect of climate on the height growth of Taiwan incense-cedar and taiwania. Height growth data for Taiwan incense-cedar came from stem analysis data and the data for taiwania were from three sets of experimental plots. Climate data were obtained from nearby climate stations. Dynamic height growth models having parameters that were functions of climate variables were fit to the height data. A Chapman–Richards function formed the basis for Taiwan incense-cedar model, and a linear model was fit to the taiwania data. Mean summer temperature and precipitation were predictor variables for Taiwan incense-cedar height growth. These variables, along with growing degree-days, were predictor variables for taiwania. Several scenarios were devised to show the effect of climate on height growth. Under the A1B climate change scenario, the height growth of taiwania is expected to increase, but the height growth of Taiwan incense-cedar will decrease slightly. The climate/height growth relationships can assist in the conservation and stewardship of these species.
    Print ISSN: 0015-752X
    Electronic ISSN: 1464-3626
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 34
    Publication Date: 2016-08-27
    Description: Large-scale transfer of reproductive material is a common phenomenon in forestry and is not only limited to recent history. Here we review the historical transfer of forest reproductive material (FRM) in Fennoscandia, the directions, their drivers, and the reported consequences for adaptation and gene pools of key forest tree species. We find that large imports of non-native FRM occurred from the 19th century onwards, partly due to prior deforestations directly associated with charcoal production for mining, extraction of timber and production of tar and pitch which have historically been important export commodities for Sweden, Norway, and Finland. In Denmark, conversion to agricultural land and the use of forests for livestock feeding was similarly important. During the subsequent reforestation efforts in Denmark, the introduction and use of non-autochthonous FRM of beech, oak and Scots pine became prevalent. Norway spruce FRM was extensively introduced to Sweden and Norway, and Scots pine FRM was imported to Sweden. Finland, in contrast, has limited records of FRM introductions. The importation of conifer seed to Norway and Sweden was initially driven by demand for large quantities of seed associated with the practice of direct seeding which prevailed until the mid-20th century. Large-scale changes to land ownership appear to have facilitated the logging of forests and subsequent seed imports for regeneration. Awareness of provenance variation in adaptive traits emerged gradually from the 19th century and led to more targeted imports of FRM to specifically improve climatic adaptation, trait qualities and growth, from the early 20th century. This, in turn, triggered the development of national regulations and guidelines from the 1930s to control the use of FRM, and marked a shift in forest legislation that had historically only been designed to control harvesting. Due to the geographical scales involved, transfers of FRM have unquestionably affected native gene pools, especially for species such as Norway spruce, Scots pine, beech, sessile and pedunculate oak, although relatively few examples of adaptive failures due to transfer have been reported.
    Print ISSN: 0015-752X
    Electronic ISSN: 1464-3626
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 35
    Publication Date: 2016-08-27
    Description: We demonstrate the efficacy of using close-range photogrammetry from a consumer grade camera as a tool in generating high-resolution, three-dimensional coloured point clouds for detailed analysis or monitoring of wheel ruts. Ground-based timber harvesting results in vehicle traffic on 12–70 per cent of the site, depending on the system used, with a variable probability of causing detrimental soil disturbance depending on climatic, hydrological and soil conditions at the time of harvest. Applying the technique described in this article can reduce the workload associated with the conventional manual measurement of wheel ruts, while providing a greatly enhanced source of information that can be used in analysing both physical and biological impact, or stored in a repository for later operation management or monitoring. Approaches for deriving and quantifying properties such as rut depths and soil displacement volumes are also presented. In evaluating the potential for widespread adoption of the method among forest or environmental managers, the study also presents the workflow and provides a comparison of the ease of use and quality of the results obtained from one commercial and two open source image processing software packages. Results from a case study showed no significant difference between packages on point cloud quality in terms of model distortion. Comparison of photogrammetric profiles against profiles measured manually resulted in root mean square errors of between 2.07 and 3.84 cm for five selected road profiles. Maximal wheel rut depth for three different models were 1.15, 0.99 and 1.01 m, and estimated rut volumes were 9.84, 9.10 and 9.09 m 3 , respectively, for 22.5 m long sections.
    Print ISSN: 0015-752X
    Electronic ISSN: 1464-3626
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 36
    Publication Date: 2016-08-27
    Description: To enhance the vigour and quality of high-graded hardwood stands, the removal of low-vigour trees is often prioritized during harvesting operations. However, northern red oak ( Quercus rubra L.) is rarely affected by defects that are indicative of imminent decline and, therefore, are less likely to be marked for harvesting. Consequently, the red oak volumes harvested during recent years were considerably lower than the estimated annual allowable cut in the public forests of Quebec, Canada. We used data from Quebec's forest inventory to identify variables associated with low-vigour red oak trees. Three groups of explanatory variables were formed to take into account tree size descriptors, inter-tree competition and stand descriptors. Logistic regression revealed that the probability of occurrence of northern red oak of low vigour increased with increasing tree diameter at breast height and dominance. Also, low-vigour oak trees were more likely to be found in stands in which total red oak basal area was low. A cut-point analysis indicated that the maximum diameter threshold for harvesting red oak ranged between 34 and 46 cm. These criteria could help forest managers formulate species-specific tree-marking rules that integrate the need to increase the red oak component in the harvested volume to a level that is closer to the annual allowable cut volume while maintaining stand vigour.
    Print ISSN: 0015-752X
    Electronic ISSN: 1464-3626
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 37
    Publication Date: 2016-08-27
    Description: Chronic browsing and inappropriate stand management are often discussed as causes for recruitment failure of tree species in temperate mixed uneven-aged forests. Continuous cover forestry is thought to produce conditions that are conducive to the recruitment of native shade-tolerant and browse-sensitive tree species such as silver fir ( Abies alba Mill.). This study used density-dependent matrix population models parameterized for three main types of fir forests in Europe (53 048 measured trees from 3183 permanent sample plots) to project the effects of Business-As-Usual uneven-aged management (BAU) and three alternative management scenarios (Non-Intervention (NON), Profit Maximization (MAX) and stand management optimized for increasing recruitment (CONS)) on fir population dynamics over 100 years. BAU, MAX and, particularly, CONS improved the population parameters if natural recruitment was sufficient regardless of site, current and historical logging and transient and equilibrium growth rates under NON. In chronically browsed and recruitment-limited fir populations with transient and equilibrium growth rates 〈1 under NON, the demographic ageing of fir can only be halted temporarily if silviculture is optimized for conservation, but none of the scenarios can prevent fir from decline. Our results suggest that a number of uneven-aged silvicultural systems, including more profit-oriented, can improve the demography of fir in central European mountain forests. However, they are not a pragmatic method to conserve fir when a population suffers from limited recruitment that causes an unmanaged population to decline.
    Print ISSN: 0015-752X
    Electronic ISSN: 1464-3626
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 38
    Publication Date: 2016-08-27
    Description: Tropical forests in Africa store large amounts of carbon and there is an urgent need for accurate methods to estimate this important carbon stock. One method to achieve this is by allometric equations but in many forest ecosystems in Africa these have not been developed. This study combined biomass data of 896 trees from five tropical countries in Africa and eight different sources to develop mixed-species regression equations for estimation of total biomass and height in Dry, Moist and Wet forest types. For estimation of total biomass, allometric equations combining diameter, height and wood density provided the best estimators in the three forest types. Because adding wood density to diameter improved height estimation, we recommend using allometric equations that combine diameter and wood density for height estimations in mixed and diverse tropical forests. Comparing ecosystem-specific (Dry, Moist and Wet) allometric equations to general allometric equations developed with combined data, and also to pan-tropical equations, showed that ecosystem-specific equations provided better estimators. The results highlight the importance of considering wood density in tree allometry for biomass as well as for tree height estimations. Although general allometric equations can be useful, this study recommends when they are available, the use of existing site-specific or ecosystem-specific allometric equations which provide better estimates.
    Print ISSN: 0015-752X
    Electronic ISSN: 1464-3626
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 39
    Publication Date: 2016-08-27
    Description: Little research has focussed on the use of low point density airborne laser scanning (ALS) technology in Mediterranean Aleppo pine ( Pinus halepensis Mill.) forest to derive key stand characteristics for forestry. The objective of this research was to develop models of Aleppo pine structural variables from ALS point clouds with a point density of 1 point m –2 and field information, in an area located in north-eastern Spain. Field stand metrics were obtained within 45 plots, 30 m in diameter. A multiple regression analysis was performed in order to develop the models for mean height, squared mean diameter, basal area, timber volume, stand density and crown ratio, which led to the following R 2 values: 0.87, 0.84, 0.89, 0.89, 0.48 and 0.69, respectively. ALS-derived metrics included in the models were maximum height, the 99th, 95th and 50th canopy height percentiles, the skewness, the kurtosis, the standard deviation, the coefficient of variation and the percentages of all and first returns from above 1 m of the ground surface. With the exception of stand density, the final models are appropriate to be used in forest management operations in Mediterranean Aleppo pine forest. This study demonstrates the usefulness of low point density ALS data to accurately estimate key structural parameters of Aleppo pine forest using an area-based approach.
    Print ISSN: 0015-752X
    Electronic ISSN: 1464-3626
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 40
    Publication Date: 2016-08-27
    Description: Compared with traditional inventory methods based on field plot sampling, airborne laser scanning (ALS) has the potential to assess forest structural properties with greater detail over space and time and at lower cost. Many national ALS survey programmes covering entire countries for topographic mapping are currently in progress and some have provided data that are in the public domain. Although the point density of these datasets is relatively low, there is an interest in developing methods that employ these types of data for categorizing different approaches to forest management. Using Finnish national ALS data with a point density of 0.91 pulses per square metre, we carried out a classification of 252 000 ha of boreal forests into silvicultural development classes (DC) used in practical forest management. Taking into account all eight DCs, the overall accuracy was 74.1 per cent and = 0.70. We conclude that the dataset is adequate for discriminating multilayered forests from even-aged ones. This result was compared with a method based on mathematical rules, which succeeded in discriminating multilayered stands with regeneration of shade-intolerant species without the need of field data for training. However, the low point density may hamper the detection of shade-tolerant understories in mature high forests with closed canopies. We, therefore, recommend the use of this supervised classification in the presence of shade-tolerant species.
    Print ISSN: 0015-752X
    Electronic ISSN: 1464-3626
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 41
    Publication Date: 2016-08-27
    Description: Improving management practices in industrial forest plantations may increase production efficiencies, thereby reducing pressures on native tropical forests for meeting global pulp needs. This study aims to predict stem volume ( V ) in plantations of fast-growing Eucalyptus hybrid clones located in southeast Brazil using field plot and airborne Light Detection and Ranging (LiDAR) data. Forest inventory attributes and LiDAR-derived metrics were calculated at 108 sample plots. The best LiDAR-based predictors of V were identified based on loadings calculated from a principal component analysis (PCA). After selecting these best predictors using PCA, we developed multiple regression models predicting V from selected LiDAR metrics. Metrics related to tree height and canopy depth were most effective for V prediction, with an overall model coefficient of determination (adj. R 2 ) of 0.87, and a root mean squared error (RMSE) of 27.60 m 3 ha –1 (i.e. relative RMSE = 9.99 per cent). We used this model to map stem V of Eucalyptus hybrid clones across the full LiDAR data extent. The accuracy and precision of our results show that LiDAR-derived V is appropriate for updating Eucalyptus forest base maps and registries in the paper and pulp supply chain. However, further studies are necessary to evaluate and compare the cost of acquisition and processing of LiDAR data against conventional V inventory in this system.
    Print ISSN: 0015-752X
    Electronic ISSN: 1464-3626
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 42
    Publication Date: 2016-06-17
    Print ISSN: 0829-318X
    Electronic ISSN: 1758-4469
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 43
    Publication Date: 2016-06-17
    Description: Water storage in the stems of woody plants contributes to their responses to short-term water shortages. To estimate the contribution of water storage to the daily water budget of trees, time lags of sap flow between different positions of trunk are used as a proxy of stem water storage. In lianas, another large group of woody species, it has rarely been studied whether stored water functions in their daily water use, despite their increasing roles in the carbon and water dynamics of tropical forests caused by their increasing abundance. We hypothesized that lianas would exhibit large time lags due to their extremely long stems, wide vessels and large volume of parenchyma in the stem. We examined time lags in sap flow, diel changes of stem volumetric water content (VWC) and biophysical properties of sapwood of 19 lianas and 26 co-occurring trees from 27 species in 4 forests (karst, tropical seasonal, flood plain and savanna) during a wet season. The plants varied in height/length from 〈5 to 〉60 m. The results showed that lianas had significantly higher saturated water content (SWC) and much lower wood density than trees. Seven of 19 liana individuals had no time lags; in contrast, only 3 of 26 tree individuals had no time lags. In general, lianas had shorter time lags than trees in our data set, but this difference was not significant for our most conservative analyses. Across trees and lianas, time lag duration increased with diurnal maximum changeable VWC but was independent of the body size, path length, wood density and SWC. The results suggest that in most lianas, internal stem water storage contributes little to daily water budget, while trees may rely more on stored water in the stem.
    Print ISSN: 0829-318X
    Electronic ISSN: 1758-4469
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 44
    Publication Date: 2016-06-17
    Description: The release of water from storage compartments to the transpiration stream is an important functional mechanism that provides the buffering of sudden fluctuations in water potential. The ability of tissues to release water per change in water potential, referred to as hydraulic capacitance, is assumed to be associated with the anatomy of storage tissues. However, information about how specific anatomical parameters determine capacitance is limited. In this study, we measured sapwood capacitance ( C ) in terminal branches and roots of five temperate tree species ( Fagus sylvatica L., Picea abies L., Quercus robur L., Robinia pseudoacacia L., Tilia cordata Mill.). Capacitance was calculated separately for water released mainly from capillary ( C I ; open vessels, tracheids, fibres, intercellular spaces and cracks) and elastic storage compartments ( C II ; living parenchyma cells), corresponding to two distinct phases of the moisture release curve. We found that C was generally higher in roots than branches, with C I being 3–11 times higher than C II . Sapwood density and the ratio of dead to living xylem cells were most closely correlated with C . In addition, the magnitude of C I was strongly correlated with fibre/tracheid lumen area, whereas C II was highly dependent on the thickness of axial parenchyma cell walls. Our results indicate that water released from capillary compartments predominates over water released from elastic storage in both branches and roots, suggesting the limited importance of parenchyma cells for water storage in juvenile xylem of temperate tree species. Contrary to intact organs, water released from open conduits in our small wood samples significantly increased C I at relatively high water potentials. Linking anatomical parameters with the hydraulic capacitance of a tissue contributes to a better understanding of water release mechanisms and their implications for plant hydraulics.
    Print ISSN: 0829-318X
    Electronic ISSN: 1758-4469
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 45
    Publication Date: 2016-06-17
    Description: A prerequisite for reliable hydraulic measurements is an accurate collection of the plant material. Thereby, the native hydraulic state of the sample has to be preserved during harvesting (i.e., cutting the plant or plant parts) and preparation (i.e., excising the target section). This is particularly difficult when harvesting has to be done under transpiring conditions. In this article, we present a harvesting and sampling protocol designed for hydraulic measurements on Malus domestica Borkh. and checked for possible sampling artefacts. To test for artefacts, we analysed the percentage loss of hydraulic conductivity, maximum specific conductivity and water contents of bark and wood of branches, taking into account conduit length, time of day of harvesting, different shoot ages and seasonal effects. Our results prove that use of appropriate protocols can avoid artefactual embolization or refilling even when the xylem is under tension at harvest. The presented protocol was developed for Malus but may also be applied for other angiosperms with similar anatomy and refilling characteristics.
    Print ISSN: 0829-318X
    Electronic ISSN: 1758-4469
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 46
    Publication Date: 2016-06-17
    Description: The formation of air emboli in the xylem during drought is one of the key processes leading to plant mortality due to loss in hydraulic conductivity, and strongly fuels the interest in quantifying vulnerability to cavitation. The acoustic emission (AE) technique can be used to measure hydraulic conductivity losses and construct vulnerability curves. For years, it has been believed that all the AE signals are produced by the formation of gas emboli in the xylem sap under tension. More recent experiments, however, demonstrate that gas emboli formation cannot explain all the signals detected during drought, suggesting that different sources of AE exist. This complicates the use of the AE technique to measure emboli formation in plants. We therefore analysed AE waveforms measured on branches of grapevine ( Vitis vinifera L. ‘Chardonnay’) during bench dehydration with broadband sensors, and applied an automated clustering algorithm in order to find natural clusters of AE signals. We used AE features and AE activity patterns during consecutive dehydration phases to identify the different AE sources. Based on the frequency spectrum of the signals, we distinguished three different types of AE signals, of which the frequency cluster with high 100–200 kHz frequency content was strongly correlated with cavitation. Our results indicate that cavitation-related AE signals can be filtered from other AE sources, which presents a promising avenue into quantifying xylem embolism in plants in laboratory and field conditions.
    Print ISSN: 0829-318X
    Electronic ISSN: 1758-4469
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 47
    Publication Date: 2016-06-17
    Description: In recent years, the validity of embolism quantification methods has been questioned, especially for long-vesseled plants. Some studies have suggested that cutting xylem while under tension, even under water, might generate artificial cavitation. Accordingly, a rehydration procedure prior to hydraulic measurements has been recommended to avoid this artefact. On the other hand, concerns have been raised that xylem refilling might occur when samples are rehydrated. Here, we explore the potential biases affecting embolism quantification for grapevine ( Vitis vinifera L.) petioles harvested under tension or after xylem relaxation. We employ direct visualization of embolism through X-ray micro-computed tomography (microCT) to test for the occurrence of fast refilling (artifactually low per cent loss of conductivity (PLC) due to rehydration prior to sample harvest) as well as excision-induced embolism (artifactually high embolism due to air introduction during harvest). Additionally, we compared the response functions of both stomatal regulation and xylem embolism to xylem pressure ( x ). Short-time (20 min) xylem tension relaxation prior to the hydraulic measurement resulted in a lower degree of embolism than found in samples harvested under native tensions, and yielded xylem vulnerability curves similar to the ones obtained using direct microCT visualization. Much longer periods of hydration (overnight) were required before xylem refilling was observed to occur. In field-grown vines, over 85% of stomatal closure occurred at less negative x than that required to induce 12% PLC. Our results demonstrate that relaxation of xylem tension prior to hydraulic measurement allows for the reliable quantification of native embolism in grapevine petioles. Furthermore, we find that stomatal regulation is sufficiently conservative to avoid transpiration-induced cavitation. These results suggest that grapevines have evolved a strategy of cavitation resistance, rather than one of cavitation tolerance (diurnal cycles of embolism and repair).
    Print ISSN: 0829-318X
    Electronic ISSN: 1758-4469
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 48
    Publication Date: 2016-06-17
    Description: Atmospheric carbon dioxide (CO 2 ) concentrations are expected to increase throughout this century, potentially fostering tree growth. A wealth of studies have examined the variation in CO 2 responses across tree species, but the extent of intraspecific variation in response to elevated CO 2 (eCO 2 ) has, so far, been examined in individual studies and syntheses of published work are currently lacking. We conducted a meta-analysis on the effects of eCO 2 on tree growth (height, stem biomass and stem volume) and photosynthesis across genotypes to examine whether there is genetic variation in growth responses to eCO 2 and to understand their dependence on photosynthesis. We additionally examined the interaction between the responses to eCO 2 and ozone (O 3 ), another global change agent. Most of the published studies so far have been conducted in juveniles and in Populus spp., although the patterns observed were not species dependent. All but one study reported significant genetic variation in stem biomass, and the magnitude of intraspecific variation in response to eCO 2 was similar in magnitude to previous analyses on interspecific variation. Growth at eCO 2 was predictable from growth at ambient CO 2 ( R 2  = 0.60), and relative rankings of genotype performance were preserved across CO 2 levels, indicating no significant interaction between genotypic and environmental effects. The growth response to eCO 2 was not correlated with the response of photosynthesis ( P  〉 0.1), and while we observed 57.7% average increases in leaf photosynthesis, stem biomass and volume increased by 36 and 38.5%, respectively, and height only increased by 9.5%, suggesting a predominant role for carbon allocation in ultimately driving the response to eCO 2 . Finally, best-performing genotypes under eCO 2 also responded better under eCO 2 and elevated O 3 . Further research needs include widening the study of intraspecific variation beyond the genus Populus and examining the interaction between eCO 2 and other environmental stressors. We conclude that significant potential to foster CO 2 -induced productivity gains through tree breeding exists, that these programs could be based upon best-performing genotypes under ambient conditions and that they would benefit from an increased understanding on the controls of allocation.
    Print ISSN: 0829-318X
    Electronic ISSN: 1758-4469
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 49
    Publication Date: 2016-06-17
    Description: The decrease of stomatal conductance ( g s ) is one of the prime responses to water shortage and the main determinant of yield limitation in fruit trees. Understanding the mechanisms related to stomatal closure in response to imposed water stress is crucial for correct irrigation management. The loss of leaf hydraulic functioning is considered as one of the major factors triggering stomatal closure. Thus, we conducted an experiment to quantify the dehydration response of leaf hydraulic conductance ( K leaf ) and its impact on g s in two Mediterranean fruit tree species, one deciduous (almond) and one evergreen (olive). Our hypothesis was that a higher K leaf would be associated with a higher g s and that the reduction in K leaf would predict the reduction in g s in both species. We measured K leaf in olive and almond during a cycle of irrigation withholding. We also compared the results of two methods to measure K leaf : dynamic rehydration kinetics and evaporative flux methods. In addition, determined g s , leaf water potential ( leaf ), vein density, photosynthetic capacity and turgor loss point. Results showed that g s was higher in almond than in olive and so was K leaf ( K max  = 4.70 and 3.42 mmol s –1  MPa –1  m –2 , in almond and olive, respectively) for leaf  〉 –1.2 MPa. At greater water stress levels than –1.2 MPa, however, K leaf decreased exponentially, being similar for both species, while g s was still higher in almond than in olive. We conclude that although the K leaf decrease with increasing water stress does not drive unequivocally the g s response to water stress, K leaf is the variable most strongly related to the g s response to water stress, especially in olive. Other variables such as the increase in abscisic acid (ABA) may be playing an important role in g s regulation, although in our study the g s –ABA relationship did not show a clear pattern.
    Print ISSN: 0829-318X
    Electronic ISSN: 1758-4469
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 50
    Publication Date: 2016-06-17
    Description: Although plant competition is recognized as a fundamental factor that limits survival and species coexistence, its relative importance on light capture efficiency and carbon gain is not well understood. Here, we propose a new framework to explain the effects of neighborhood structures and light availability on plant attributes and their effect on plant performance in two understory shade-tolerant species ( Palicourea padifolia (Roem. & Schult.) C.M. Taylor & Lorence and Psychotria elata (Swartz)) within two successional stages of a cloud forest in Costa Rica. Features of plant neighborhood physical structure and light availability, estimated by hemispherical photographs, were used to characterize the plant competition. Plant architecture, leaf attributes and gas exchange parameters extracted from the light-response curve were used as functional plant attributes, while an index of light capture efficiency (silhouette to total area ratio, averaged over all viewing angles, STAR) and carbon gain were used as indicators of plant performance. This framework is based in a partial least square Path model, which suggests that changes in plant performance in both species were affected in two ways: (i) increasing size and decreasing distance of neighbors cause changes in plant architecture (higher crown density and greater leaf dispersion), which contribute to lower STAR and subsequently lower carbon gain; and (ii) reductions in light availability caused by the neighbors also decrease plant carbon gain. The effect of neighbors on STAR and carbon gain were similar for the two forests sites, which were at different stages of succession, suggesting that the architectural changes of the two understory species reflect functional convergence in response to plant competition. Because STAR and carbon gain are variables that depend on multiple plant attributes and environmental characteristics, we suggest that changes in these features can be used as a whole-plant response approach to detect environmental filtering in highly diverse tropical forest communities.
    Print ISSN: 0829-318X
    Electronic ISSN: 1758-4469
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 51
    Publication Date: 2016-06-17
    Description: The ability of plants to sequester carbon is highly variable over the course of the year and reflects seasonal variation in photosynthetic efficiency. This seasonal variation is most prominent during autumn, when leaves of deciduous tree species such as sugar maple ( Acer saccharum Marsh.) undergo senescence, which is associated with downregulation of photosynthesis and a change of leaf color. The remote sensing of leaf color by spectral reflectance measurements and digital repeat images is increasingly used to improve models of growing season length and seasonal variation in carbon sequestration. Vegetation indices derived from spectral reflectance measurements and digital repeat images might not adequately reflect photosynthetic efficiency of red-senescing tree species during autumn due to the changes in foliar pigment content associated with autumn phenology. In this study, we aimed to assess how effectively several widely used vegetation indices capture autumn phenology and reflect the changes in physiology and photosynthetic pigments during autumn. Chlorophyll fluorescence and pigment content of green, yellow, orange and red leaves were measured to represent leaf senescence during autumn and used as a reference to validate and compare vegetation indices derived from leaf-level spectral reflectance measurements and color analysis of digital images. Vegetation indices varied in their suitability to track the decrease of photosynthetic efficiency and chlorophyll content despite increasing anthocyanin content. Commonly used spectral reflectance indices such as the normalized difference vegetation index and photochemical reflectance index showed major constraints arising from a limited representation of gradual decreases in chlorophyll content and an influence of high foliar anthocyanin levels. The excess green index and green–red vegetation index were more suitable to assess the process of senescence. Similarly, digital image analysis revealed that vegetation indices such as Hue and normalized difference index are superior compared with the often-used green chromatic coordinate. We conclude that indices based on red and green color information generally represent autumn phenology most efficiently.
    Print ISSN: 0829-318X
    Electronic ISSN: 1758-4469
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 52
    Publication Date: 2016-06-17
    Description: Roots interact with soil properties and irrigation water quality leading to changes in root growth, structure and function. We studied these interactions in an orchard and in lysimeters with clay and sandy loam soils. Minirhizotron imaging and manual sampling showed that root growth was three times lower in the clay relative to sandy loam soil. Treated wastewater (TWW) led to a large reduction in root growth with clay (45–55%) but not with sandy loam soil (〈20%). Treated wastewater increased salt uptake, membrane leakage and proline content, and decreased root viability, carbohydrate content and osmotic potentials in the fine roots, especially in clay. These results provide evidence that TWW challenges and damages the root system. The phenology and physiology of root orders were studied in lysimeters. Soil type influenced diameter, specific root area, tissue density and cortex area similarly in all root orders, while TWW influenced these only in clay soil. Respiration rates were similar in both soils, and root hydraulic conductivity was severely reduced in clay soil. Treated wastewater increased respiration rate and reduced hydraulic conductivity of all root orders in clay but only of the lower root orders in sandy loam soil. Loss of hydraulic conductivity increased with root order in clay and clay irrigated with TWW. Respiration and hydraulic properties of all root orders were significantly affected by sodium-amended TWW in sandy loam soil. These changes in root order morphology, anatomy, physiology and hydraulic properties indicate rapid and major modifications of root systems in response to differences in soil type and water quality.
    Print ISSN: 0829-318X
    Electronic ISSN: 1758-4469
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 53
    Publication Date: 2016-06-01
    Description: Adequate food intake being necessary for good health and life suggests that food consumption has significant long-term effects on human welfare. This article develops an economic and econometric analysis of the dynamics of food demand. The model builds on duality and the benefit function. The research involves the specification and estimation of dynamic price-dependent demands as representations of marginal benefits. Applied to US aggregate data over the period 1948–2010, the analysis uncovers strong statistical evidence of demand dynamics, especially for food. We find that the negative effect of food consumption on the marginal benefit of food becomes much stronger in the long run. We also find that, while food and service are always complements, the strength of this complementarity relationship increases sharply in the longer run.
    Print ISSN: 0165-1587
    Electronic ISSN: 1464-3618
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition , Economics
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 54
    Publication Date: 2016-06-01
    Description: We extend the existing literature on the income stabilisation tool (IST) by investigating the influence of farm and farmers' characteristics on potential indemnification applying double-hurdle models on a rich panel data set on Swiss farms. We find more likely and higher indemnifications for part-time and low-income farmers. Thus, the IST might become a new transfer instrument hampering the structural change. Even though the estimated costs of the IST are low compared with the current direct payment level in Switzerland, both policy measures are partly substitutes with respect to income risk reductions implying more frequent and higher indemnification through the IST if direct payments are reduced.
    Print ISSN: 0165-1587
    Electronic ISSN: 1464-3618
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition , Economics
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 55
    Publication Date: 2016-06-01
    Description: This study explores an apparently paradoxical finding in farming and fishing: low economic returns, but a high rate of occupational transmission across generations of farmers and fishers. Using a sibling model containing 11,924 children of Swedish farmers and fishers in 2012, we estimate that farmers' sons who became farmers received 28 per cent lower income than same-sex siblings with a career outside farming. For farmers' daughters and fishers' sons, the income gap was about 22 per cent relative to same-sex siblings. Our conclusion is that the decision to become a fisher or a farmer is largely determined by non-pecuniary factors.
    Print ISSN: 0165-1587
    Electronic ISSN: 1464-3618
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition , Economics
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 56
    Publication Date: 2016-06-01
    Description: Understanding the motives and risk attitudes of producers to engage in sustainable practices is important for policy-makers who wish to increase the likelihood of adoption and improve the design of incentives. This article examines the underlying motives of producers to adopt sustainable practices. We focus on expected economic, social and personal rewards and analyse the role of producers' financial risk perception and risk tolerance. Results from personal interviews with 164 hog producers show that the adoption of sustainable practices is affected by expected economic rewards but not by social and personal rewards. Further, while perceived risk is a barrier to the adoption of sustainable practices, risk tolerance is a positive moderator of the relationship between economic rewards and adoption. In addition, perceived tax benefits and turnover have a significant positive relationship with adoption, while education and age do not play a role.
    Print ISSN: 0165-1587
    Electronic ISSN: 1464-3618
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition , Economics
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 57
    Publication Date: 2016-06-01
    Description: This work deals with issues relating to multiperiod hedging ratios (MHRs). First, we derive an analytical formula for the MHR starting from the triangular representation of a cointegrated system. Second, using both overlapping and non-overlapping price changes, we investigate the properties of OLS MHR. Third, we resort to simulated data to investigate the performance of MHR estimators. Unlike previous studies, we do not use real data whose data generating process is unknown; instead we run a Monte Carlo exercise to investigate estimators and compare them with theoretical measures. Finally, we apply our approach to real data for a hedging related to soft wheat.
    Print ISSN: 0165-1587
    Electronic ISSN: 1464-3618
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition , Economics
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 58
    Publication Date: 2016-06-01
    Description: This article focuses on the main drivers of the distribution of the Rural Development Policy expenditure throughout the European Union (EU). Ex-post funds distribution across EU NUTS3 regions is considered. Three effects are considered as major drivers: a ‘country effect’; a ‘rural effect’ (i.e. the more rural a region the larger the amount of support); a ‘pure spatial effect’ (i.e. the influence of bordering regions and of their degree of rurality). These effects are estimated adopting alternative spatial model specifications: Spatial Durbin Model, Spatial Error Model, Spatial AutoRegressive Model and Spatial Lag of X Model. Results slightly differ across alternative specifications and definitions of rurality, but prevalent evidence suggests that rurality matters in a counterintuitive direction while also spatial spillovers play a role.
    Print ISSN: 0165-1587
    Electronic ISSN: 1464-3618
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition , Economics
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 59
    Publication Date: 2016-06-01
    Print ISSN: 0165-1587
    Electronic ISSN: 1464-3618
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition , Economics
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 60
    Publication Date: 2016-09-01
    Description: Accurately scaling sap flux observations to tree or stand levels requires accounting for variation in sap flux between wood types and by depth into the tree. However, existing models for radial variation in axial sap flux are rarely used because they are difficult to implement, there is uncertainty about their predictive ability and calibration measurements are often unavailable. Here we compare different models with a diverse sap flux data set to test the hypotheses that radial profiles differ by wood type and tree size. We show that radial variation in sap flux is dependent on wood type but independent of tree size for a range of temperate trees. The best-fitting model predicted out-of-sample sap flux observations and independent estimates of sapwood area with small errors, suggesting robustness in the new settings. We develop a method for predicting whole-tree water use with this model and include computer code for simple implementation in other studies.
    Print ISSN: 0829-318X
    Electronic ISSN: 1758-4469
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 61
    Publication Date: 2016-09-01
    Description: Surface winds have declined in many regions of the world over the past few decades. These trends are referred to as global stilling and have recently been observed in the Western Cape Province of South Africa. The potential consequences of such changes on ecosystem function and productivity are a particular concern for the highly diverse and endemic local flora, largely associated with the fynbos biome. Yet, few studies have directly examined the impact of wind in the region. In this study, we explored the importance of wind and other drivers of plant transpiration ( E ) in a stand of Leucospermum conocarpodendron (L.) Buek trees on the Cape Peninsula. Wind speeds can be high in the Cape and could play an important role in influencing the rate of E . Overall, the influence of wind appeared to be significantly greater at night than during the day. While daytime E responded most strongly to changes in solar radiation ( R 2  = 0.79) and vapour pressure deficit ( R 2  = 0.57–0.67), night-time E ( E n ) was primarily driven by wind speed ( R 2  = 0.30–0.59). These findings have important implications for stilling and other aspects of climate change. Since E n was found to be a regular and significant ( P  〈 0.00) component of total daily E (10–27%), plants may conserve water should stilling continue. Still, the extent of this could be offset by strong daytime drivers. As such, plant water consumption will most likely increase in response to a warmer and drier climate. Changes in other biophysical variables are, however, clearly important to consider in the current debate on the impact of climate change.
    Print ISSN: 0829-318X
    Electronic ISSN: 1758-4469
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 62
    Publication Date: 2016-09-01
    Print ISSN: 0829-318X
    Electronic ISSN: 1758-4469
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 63
    Publication Date: 2016-09-01
    Description: Water transport from soils to the atmosphere is critical for plant growth and survival. However, we have a limited understanding about many portions of the whole-tree hydraulic pathway, because the vast majority of published information is on terminal branches. Our understanding of mature tree trunk hydraulic physiology, in particular, is limited. The hydraulic vulnerability segmentation hypothesis (HVSH) stipulates that distal portions of the plant (leaves, branches and roots) should be more vulnerable to embolism than trunks, which are nonredundant organs that require a massive carbon investment. In the current study, we compared vulnerability to loss of hydraulic function, leaf and xylem water potentials and the resulting hydraulic safety margins (in relation to the water potential causing 50% loss of hydraulic conductivity) in leaves, branches, trunks and roots of four angiosperms and four conifer tree species. Across all species, our results supported strongly the HVSH as leaves and roots were less resistant to embolism than branches or trunks. However, branches were consistently more resistant to embolism than any other portion of the plant, including trunks. Also, calculated whole-tree vulnerability to hydraulic dysfunction was much greater than vulnerability in branches. This was due to hydraulic dysfunction in roots and leaves at less negative water potentials than those causing branch or trunk dysfunction. Leaves and roots had narrow or negative hydraulic safety margins, but trunks and branches maintained positive safety margins. By using branch-based hydraulic information as a proxy for entire plants, much research has potentially overestimated embolism resistance, and possibly drought tolerance, for many species. This study highlights the necessity to reconsider past conclusions made about plant resistance to drought based on branch xylem only. This study also highlights the necessity for more research of whole-plant hydraulic physiology to better understand strategies of plant drought tolerance and the critical control points within the hydraulic pathway.
    Print ISSN: 0829-318X
    Electronic ISSN: 1758-4469
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 64
    Publication Date: 2016-09-01
    Description: Freezing resistance through avoidance or tolerance of extracellular ice nucleation is important for plant survival in habitats with frequent subzero temperatures. However, the role of cell walls in leaf freezing resistance and the coordination between leaf and stem physiological processes under subzero temperatures are not well understood. We studied leaf and stem responses to freezing temperatures, leaf and stem supercooling, leaf bulk elastic modulus and stem xylem vessel size of six Patagonian shrub species from two sites (plateau and low elevation sites) with different elevation and minimum temperatures. Ice seeding was initiated in the stem and quickly spread to leaves, but two species from the plateau site had barriers against rapid spread of ice. Shrubs with xylem vessels smaller in diameter had greater stem supercooling capacity, i.e., ice nucleated at lower subzero temperatures. Only one species with the lowest ice nucleation temperature among all species studied exhibited freezing avoidance by substantial supercooling, while the rest were able to tolerate extracellular freezing from –11.3 to –20 °C. Leaves of species with more rigid cell walls (higher bulk elastic modulus) could survive freezing to lower subzero temperatures, suggesting that rigid cell walls potentially reduce the degree of physical injury to cell membranes during the extracellular freezing and/or thaw processes. In conclusion, our results reveal the temporal–spatial ice spreading pattern (from stem to leaves) in Patagonian shrubs, and indicate the role of xylem vessel size in determining supercooling capacity and the role of cell wall elasticity in determining leaf tolerance of extracellular ice formation.
    Print ISSN: 0829-318X
    Electronic ISSN: 1758-4469
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 65
    Publication Date: 2016-09-01
    Description: We aim to achieve a mechanistic understanding of the eco-physiological processes in Larix decidua and Pinus mugo var. uncinata growing on north- and south-facing aspects in the Swiss National Park in order to distinguish the short- and long-term effects of a changing climate. To strengthen the interpretation of the 18 O signal in tree rings and its coherence with the main factors and processes driving evaporative 18 O needle water enrichment, we analyzed the 18 O in needle, xylem and soil water over the growing season in 2013 and applied the mechanistic Craig–Gordon model (1965) for the short-term responses. We found that 18 O needle water strongly reflected the variability of relative humidity mainly for larch, while only 18 O in pine xylem water showed a strong link to 18 O in precipitation. Larger differences in offsets between modeled and measured 18 O needle water for both species from the south-facing aspects were detected, which could be explained by the high transpiration rates. Different soil water and needle water responses for the two species indicate different water-use strategies, further modulated by the site conditions. To reveal the long-term physiological response of the studied trees to recent and past climate changes, we analyzed 13 C and 18 O in wood chronologies from 1900 to 2013. Summer temperatures as well as summer and annual amount of precipitations are important factors for growth of both studied species from both aspects. However, mountain pine trees reduced sensitivity to temperature changes, while precipitation changes come to play an important role for the period from 1980 to 2013. Intrinsic water-use efficiency (WUEi) calculated for larch trees since the 1990s reached a saturation point at elevated CO 2 . Divergent trends between pine WUEi and 18 O are most likely indicative of a decline of mountain pine trees and are also reflected in decoupling mechanisms in the isotope signals between needles and tree-rings.
    Print ISSN: 0829-318X
    Electronic ISSN: 1758-4469
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 66
    Publication Date: 2016-09-01
    Description: We investigated the effects of historic soil chemistry changes associated with acid rain, i.e., reduced soil pH and a shift from nitrogen (N)- to phosphorus (P)-limitation, on the coordination of leaf water demand and xylem hydraulic supply traits in two co-occurring temperate tree species differing in growth rate. Using a full-factorial design (N  x  P  x  pH), we measured leaf nutrient content, water relations, leaf-level and canopy-level gas exchange, total biomass and allocation, as well as stem xylem anatomy and hydraulic function for greenhouse-grown saplings of fast-growing Acer rubrum (L.) and slow-growing Quercus alba (L.). We used principle component analysis to characterize trait coordination. We found that N-limitation, but not P-limitation, had a significant impact on plant water relations and hydraulic coordination of both species. Fast-growing A. rubrum made hydraulic adjustments in response to N-limitation, but trait coordination was variable within treatments and did not fully compensate for changing allocation across N-availability. For slow-growing Q. alba , N-limitation engendered more strict coordination of leaf and xylem traits, resulting in similar leaf water content and hydraulic function across all treatments. Finally, low pH reduced the propensity of both species to adjust leaf water relations and xylem anatomical traits in response to nutrient manipulations. Our data suggest that a shift from N- to P-limitation has had a negative impact on the water relations and hydraulic function of A. rubrum to a greater extent than for Q. alba . We suggest that current expansion of A. rubrum populations could be tempered by acidic N-deposition, which may restrict it to more mesic microsites. The disruption of hydraulic acclimation and coordination at low pH is emphasized as an interesting area of future study.
    Print ISSN: 0829-318X
    Electronic ISSN: 1758-4469
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 67
    Publication Date: 2016-09-01
    Description: Shoot size and other shoot properties more or less follow the availability of light, but there is also evidence that the topological position in a tree crown has an influence on shoot development. Whether the hydraulic properties of new shoots are more regulated by the light or the position affects the shoot acclimation to changing light conditions and thereby to changing evaporative demand. We investigated the leaf-area-specific conductivity (and its components sapwood-specific conductivity and Huber value) of the current-year shoots of Scots pine ( Pinus sylvestris L.) in relation to light environment and topological position in three different tree classes. The light environment was quantified in terms of simulated transpiration and the topological position was quantified by parent branch age. Sample shoot measurements included length, basal and tip diameter, hydraulic conductivity of the shoot, tracheid area and density, and specific leaf area. In our results, the leaf-area-specific conductivity of new shoots declined with parent branch age and increased with simulated transpiration rate of the shoot. The relation to transpiration demand seemed more decisive, since it gave higher R 2 values than branch age and explained the differences between the tree classes. The trend of leaf-area-specific conductivity with simulated transpiration was closely related to Huber value, whereas the trend of leaf-area-specific conductivity with parent branch age was related to a similar trend in sapwood-specific conductivity.
    Print ISSN: 0829-318X
    Electronic ISSN: 1758-4469
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 68
    facet.materialart.
    Unknown
    Oxford University Press
    Publication Date: 2016-08-20
    Print ISSN: 2040-5790
    Electronic ISSN: 2040-5804
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition , Economics
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 69
    Publication Date: 2016-08-20
    Description: This article examines the impact that Ontario’s Greenbelt legislation, a farmland preservation policy implemented in 2005 that permanently protects over 1.8 million acres of land from non-agricultural development, has on farmers’ exit and investment decisions. There are conflicting hypotheses regarding the impacts that farmland preservation could have on farmers’ management decisions with respect to investment or disinvestment, and there is a lack of evidence in the literature regarding the nature of such impacts. To address this issue, this article uses a farm-level panel data set to estimate the impacts of the Greenbelt policy on farm exit and on farm investment. The Greenbelt policy is found to have influenced both farm exit and farm investment decisions, with the impact varying depending on location within the Greenbelt. In particular, the results indicate evidence of a negative impact on farm investment, which is contrary to one of the objectives of the Greenbelt policy.
    Keywords: Q12 - Micro Analysis of Farm Firms, Farm Households, and Farm Input Markets, Q24 - Land, R52 - Land Use and Other Regulations
    Print ISSN: 2040-5790
    Electronic ISSN: 2040-5804
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition , Economics
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 70
    Publication Date: 2016-08-20
    Description: This paper reviews the situation in the agricultural sector and food security in Cuba, and particularly the transformations that have (not) taken place since 1990. We compare the Cuban transition with transitions in other "transition countries" and show that Cuba does not easily fit into one of the transition patterns, and, in a way, has characteristics of "a bit of everything". To conclude, we discuss the (potential) effects of the recent policy changes and the new economic reforms that were announced.
    Keywords: O13 - Agriculture ; Natural Resources ; Energy ; Environment ; Other Primary Products, P21 - Planning, Coordination, and Reform, Q13 - Agricultural Markets and Marketing ; Cooperatives ; Agribusiness, Q18 - Agricultural Policy ; Food Policy
    Print ISSN: 2040-5790
    Electronic ISSN: 2040-5804
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition , Economics
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 71
    Publication Date: 2016-08-20
    Description: The increased availability of high resolution data and computing power has spurred enormous interest in "Big Data". While analysts typically source data from a wide variety of agencies, even within the USDA no comprehensive data warehouse exists with which researchers can interact. This leads to massive duplication in efforts, inefficient data sourcing, and great potential for error. The purpose of this article is to provide a brief overview of this state of affairs within the community. An overview of a prototype warehouse is also provided, as are thoughts on future directions.
    Keywords: C80 - General, Q00 - General
    Print ISSN: 2040-5790
    Electronic ISSN: 2040-5804
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition , Economics
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 72
    facet.materialart.
    Unknown
    Oxford University Press
    Publication Date: 2016-08-20
    Print ISSN: 2040-5790
    Electronic ISSN: 2040-5804
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition , Economics
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 73
    Publication Date: 2016-08-27
    Description: We review the use of leaf area metrics (LAM) for assessing and managing dryland forests. We propose a framework integrating individual tree to whole-ecosystem metrics representing a variety of forest features and review theory, empirical evidence and knowledge gaps. Four basic concepts underlie the LAM framework: (1) Max-LAI – an ecosystem can be characterized by an upper potential leaf area index (LAI) dictated mainly by water availability, (2) Leaf area distribution – the distribution of leaf area is proportional to the distribution of resources among vegetation components, (3) Safe-LAI – maintaining Ecosystem-LAI below Max-LAI is a way to reduce drought stress and (4) tree leaf area ( TLA ) – the leaf area of an individual tree as a proportion of its potential TLA, represents its vigour. Implementation of the LAM strategy requires the following: (1) better understanding how edaphic conditions and vegetation characteristics interact with climate in determining Max-LAI , (2) better understanding how leaf area is related to water use across species, vegetation strata and light regimes, (3) better understanding the interaction between LAI development and stand dynamics, (4) better capability of measuring or estimating individual tree leaf area and (5) development of species-specific references for tree vigour based on leaf area. The LAM strategy is promising for managing dryland forests under increasing drought stress.
    Print ISSN: 0015-752X
    Electronic ISSN: 1464-3626
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 74
    Publication Date: 2016-08-27
    Description: To account for ecological objectives in forest management planning, potential habitats need to be mapped, characterized and evaluated for utility in alternative management practices. Airborne laser scanning (ALS) is increasingly used to derive predictive maps of habitat quality. Unlike ecologically driven approaches that require spatially and temporally co-located training data of the specific species, we tested whether indicative information on the habitat potential could be obtained by means of an unsupervised classification of ALS data. Based on a literature review, altogether five ALS features quantifying vegetation height, cover and diversity were expected to capture the essential variation in the habitat requirements of western capercaillie ( Tetrao urogallus L.) and hazel grouse ( Tetrastes bonasia L.), which are the most important game birds occurring in the studied area. The features were extracted from sparse density, leaf-off ALS data at a resolution of 256 m 2 and partitioned using an unsupervised k -means algorithm. By analysing the persistence of the cluster ensemble formed by the partitioning, altogether 158 plots in 16 structural classes were assigned for field measurements to determine which real-world forest phenomena affected the clustering. The clustering was found to stratify the area mainly in terms of size-related attributes such as timber volume and basal area. The understorey, shrub and herb layers had less correspondence with the clustering, indicating that an unsupervised classification is not directly suitable for habitat mapping. The result was improved using empirical threshold values for the ALS features determined according to the plots labelled as the most potential habitats in the field measurements. This semi-supervised classification of the data indicated 4 per cent of the total forest area as suitable for the specific species, which appears a reasonable estimate of the core area of the habitats considered. Overall, the partitioning formed aggregated, stand-like spatial patterns, even though the neighbourhoods of the individual 256 m 2 cells were not considered at all. The result could be further refined by spatial optimization to produce indicative maps for forest management planning with ALS as the sole data source.
    Print ISSN: 0015-752X
    Electronic ISSN: 1464-3626
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 75
    Publication Date: 2016-08-27
    Description: The oak wilt fungus, Ceratocystis fagacearum, is native to North America, and is a threat to oaks in Europe. Therefore, the European Union has regulated the importation of oak wood from the US into Europe. We developed a pathway model to calculate the exposure of oak trees in Europe to the fungus under different regulatory scenarios and thus evaluate the effectiveness of the measures. The model describes the import, inspection and treatments of wood, as well as the trade among European countries and processing to sawn wood, final product and residues. The model quantifies the frequency of escape of the fungus from wood with a vector, and the transfer to host trees. Existing regulations reduce exposure by a factor 〉30 000 compared with a scenario without regulation. Exposure is highest around European ports and during transportation of wood across Europe. Wood treatments and shipment to a restricted set of ports are effective measures, each reducing exposure by more than 90%. Pathway modelling is a promising tool to study entry pathways of alien tree pests and evaluate risk reduction options: it provides a systematic and transparent approach but is limited by availability of biological data.
    Print ISSN: 0015-752X
    Electronic ISSN: 1464-3626
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 76
    Publication Date: 2016-08-27
    Description: Alternative methods have been used for developing tree basic and generalized height–diameter models, including non-linear least-squares regression, non-linear mixed-effects method, quantile regression (QR) and a generalized additive model (GAM). However, these approaches have not been thoroughly compared. The purpose of this study was to compare these methods applied to tree height–diameter models for larch plantations in northern and northeastern China. The data were obtained from an extensive database curated by the China National Forest Inventory (NFI) that covers a wide distribution and range of stand conditions, including 5684 paired heights and diameters in 342 plots. Random effects at the Province, species and plot levels, and a combination of Province and species into the basic and generalized H – D models were incorporated. This study demonstrated that the mixed-effects basic model provided the best performance for model fitting and validation; QR could represent variable H–D relationships at different quantiles and the GAM was a suitable alternative for flexible modelling of the H–D relationship, especially for generalized H–D model. This finding indicates that the mixed-effects basic model does not require additional variables and is an adequate tool for generating missing height measurements for larch plantations in northern and northeastern China.
    Print ISSN: 0015-752X
    Electronic ISSN: 1464-3626
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 77
    Publication Date: 2016-07-09
    Description: Using panel data of retail purchases, we measure the effects of the introduction, and later removal, of a bottled-water tax in the state of Washington. We use a difference-in-differences approach to measure effects of the tax against untreated stores (in comparable control states) and untreated weeks (the pre-period). We further estimate triple-difference specifications comparing bottled water to juice and milk substitute products. Our results show that, when imposed, the tax causes bottled water sales to drop by nearly 6% in our preferred specification. Sales never fully recover, even after the tax removal. In terms of the heterogeneity of this effect, we find larger quantity drops in high tax rate areas and in the lowest and highest quintile income areas.
    Keywords: C23 - Models with Panel Data, D12 - Consumer Economics: Empirical Analysis, H20 - General, H23 - Externalities ; Redistributive Effects ; Environmental Taxes and Subsidies, Q53 - Air Pollution ; Water Pollution ; Noise ; Hazardous Waste ; Solid Waste ; Recycling
    Print ISSN: 0002-9092
    Electronic ISSN: 1467-8276
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition , Economics
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 78
    Publication Date: 2016-07-09
    Description: The U.S. tobacco market has experienced a shift toward noncigarette tobacco products. We examined the degree of habit formation and the role of advertising for cigarettes, little cigars/cigarillos, large cigars, e-cigarettes, and smokeless tobacco using market-level scanner data for convenience stores from 2009 to 2013. Results based on a dynamic demand system show that while all tobacco products are habitual, e-cigarettes are the most habitual product. More choices of flavors, less restrictions on its use in public places, less documented harmful effects, and a higher upfront cost might explain the higher degree of habit formation for e-cigarettes. We also find that e-cigarettes did not substitute for or complement cigarettes. The results imply that e-cigarettes may serve as a gateway to nicotine addiction but not necessarily to cigarette smoking. Regarding advertising, cigarette magazine advertising did not affect cigarette demand, while e-cigarette TV advertising increased e-cigarette demand with a positive spillover to cigarette demand. Such results may help explain e-cigarettes’ recent success in sales and imply that e-cigarette TV advertising might undermine efforts to reduce cigarette smoking. Advertising was also found to affect the degree of habit formation for cigarettes, large cigars, and e-cigarettes.
    Keywords: D12 - Consumer Economics: Empirical Analysis, I18 - Government Policy ; Regulation ; Public Health, M37 - Advertising
    Print ISSN: 0002-9092
    Electronic ISSN: 1467-8276
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition , Economics
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 79
    Publication Date: 2016-07-09
    Description: If agricultural subsidies are largely capitalized into farmland values through their effect on rental rates, then expanding support for agriculture may not benefit farmers who rent the land they farm. Existing evidence on the incidence of subsidies on cash rental rates is mixed. Identification is obscured by unobserved or imprecisely measured factors that tend to be correlated with subsidies, especially land quality and time-varying factors like commodity prices and adverse weather events. A problem that has received less attention is the fact that subsidies and land quality on rented land may differ from owned land. Since most farms possess both rented and owned acreage, farm-level measures of subsidies, land values, and rental rates may bias estimated incidence. Using a new, field-level data set that, for the first time, precisely links subsidies to land parcels, we show that this bias is considerable: where farm-level estimates suggest an incidence of 42–49 cents of the marginal subsidy dollar, field-level estimates from the same farms indicate that landlords capture just 20–28 cents. The size of the farm and the duration of the rental arrangement have substantial effects. Incidence falls by 5–15 cents when doubling total operated acres, and the incidence falls by 0.1–0.8 cents with each additional year of the rental arrangement. Low incidence of subsidies on rents combined with the farm-size and duration effects suggest that farmers renting land have monopsony power.
    Keywords: H22 - Incidence, Q14 - Agricultural Finance, Q15 - Land Ownership and Tenure ; Land Reform ; Land Use ; Irrigation, Q18 - Agricultural Policy ; Food Policy
    Print ISSN: 0002-9092
    Electronic ISSN: 1467-8276
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition , Economics
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 80
    Publication Date: 2016-07-09
    Description: Many countries adjust their trade policies counter-cyclically with food prices, to the extent that the use of restrictions by food-exporting countries has occasionally threatened the food security of food-importing countries. These trade policies are inconsistent with the terms-of-trade motivation often retained to characterize the payoff frontier of self-enforcing trade agreements, as they can worsen the terms of trade of the countries that apply them. This article analyzes trade policy coordination when trade policies are driven by terms-of-trade effects and a desire to reduce domestic food price volatility. This framework implies that importing and exporting countries have incentives to deviate from cooperation at different periods: the latter when prices are high and the former when prices are low. Since staple food prices tend to have asymmetric distributions, with more prices below than above the mean but with occasional spikes, a self-enforcing agreement generates asymmetric outcomes. Without cooperation, an importing country uses its trade policy more frequently because of the concentration of prices below the mean, but an exporting country has a greater incentive to deviate from a cooperative trade policy because positive deviations from the mean price are larger than negative ones. Thus, the asymmetry of the distribution of commodity prices can make it more difficult to discipline export taxes than tariffs in trade agreements.
    Keywords: F13 - Trade Policy ; International Trade Organizations, Q17 - Agriculture in International Trade, Q18 - Agricultural Policy ; Food Policy
    Print ISSN: 0002-9092
    Electronic ISSN: 1467-8276
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition , Economics
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 81
    Publication Date: 2016-07-09
    Description: This paper examines the agglomeration hypothesis, which states that a firm’s productive efficiency is increased by closer proximity to other firms. Using a stochastic input distant function with heteroskedastic inefficiency effects, we find that the density of Ontario dairy farms has a significant positive economic effect on production efficiency. The finding has implications for understanding agricultural firm location and farmer-led efforts to preserve agricultural farming activities in specific locations.
    Keywords: D24 - Production ; Cost ; Capital and Total Factor Productivity ; Capacity, Q12 - Micro Analysis of Farm Firms, Farm Households, and Farm Input Markets, R11 - Regional Economic Activity: Growth, Development, and Changes
    Print ISSN: 0002-9092
    Electronic ISSN: 1467-8276
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition , Economics
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 82
    Publication Date: 2016-07-09
    Description: The generalized expected utility literature typically assumes an absence of judgment bias in the individual perception of probabilities when inferring risk preferences. This assumption is in disagreement with many other studies that document such bias. We show that models of preference anomalies are mathematically equivalent to models of perception anomalies when estimating perceptions and/or preferences based on observable risky choice data. Empirical models admitting both involve multiplicative functions of common variables and are discernible only by assuming specifications that arbitrarily separate the two. This inability to separately identify preferences and probability perceptions is not readily solved by experimental means. Vastly different combinations of preference and perception modifications fit behavioral data identically, implying that Arrow-Pratt risk aversion estimates are arbitrary. In contrast, the risk premium and certainty equivalent are identifiable without unverifiable and untestable separating assumptions, and provide sufficient statistics for policy and welfare analysis regardless.
    Keywords: D03 - Behavioral Economics ; Underlying Principles, D81 - Criteria for Decision-Making under Risk and Uncertainty, D84 - Expectations ; Speculations
    Print ISSN: 0002-9092
    Electronic ISSN: 1467-8276
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition , Economics
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 83
    Publication Date: 2016-07-09
    Print ISSN: 0002-9092
    Electronic ISSN: 1467-8276
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition , Economics
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 84
    Publication Date: 2016-07-09
    Description: We analyze the effects of the interactions that the two pillars of the European Union Common Agricultural Policy—market support and rural development—have on farmers’ uptake of organic farming practices. Special attention is given to the 2003 reform, which substantially altered the relative importance of the two types of support by decoupling direct agricultural payments from the production of a specific crop. In our empirical analysis we study the case of Sweden, making use of the variation in the timing of farmers’ decisions regarding participation in support programs. We estimate a dynamic non-linear unobserved effects probit model to account for unobserved individual heterogeneity and state dependence. Our results indicate the existence of a negative effect of the market support system in place when organic farming techniques were adopted before the 2003 reform. However, this effect is reversed by the introduction of decoupling. Furthermore, the effects of support differ between certified and non-certified organic production: both pillars have significant effects on non-certified organic farming, whereas certified organic farming is exclusively driven by agro-environmental subsidies.
    Keywords: C23 - Models with Panel Data, Q12 - Micro Analysis of Farm Firms, Farm Households, and Farm Input Markets, Q18 - Agricultural Policy ; Food Policy
    Print ISSN: 0002-9092
    Electronic ISSN: 1467-8276
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition , Economics
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 85
    Publication Date: 2016-07-09
    Description: This article investigates the sources of profitability change at the farm level, by farm size and specialization, with an application to a sample of 256 farms in Kansas from 1993 to 2010. Using the Lowe index method, profitability change is decomposed into changes in total factor productivity and terms of trade. The nonparametric data envelopment analysis method is used to further decompose total factor productivity into technical change and different measures of output-oriented efficiency change. Finally, the system-Generalized Methods of Moments approach is employed to investigate the dynamic relationship between different components of productivity on farm profitability. Results indicate that profitability change is mainly driven by total factor productivity change. The main source of total factor productivity change is technical change. The upward-shifting frontier results in declining technical efficiency. Results point towards the need to support research and development without ignoring efforts to encourage the uptake of existing technologies.
    Keywords: D24 - Production ; Cost ; Capital and Total Factor Productivity ; Capacity, O47 - Measurement of Economic Growth ; Aggregate Productivity ; Cross-Country Output Convergence, Q10 - General
    Print ISSN: 0002-9092
    Electronic ISSN: 1467-8276
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition , Economics
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 86
    Publication Date: 2016-07-09
    Description: Rapid conversion of private land for agricultural and urban use has raised concern worldwide over the loss of ecological services. To inform conservation policy, we model privately optimal land use decisions using a real options framework that assumes both the ecological and commercial values of land are stochastic and that land conversion is irreversible. We analyze permanent and temporary land conservation policy incentives using this dynamic framework to guide policy makers interested in designing efficient payment mechanisms to achieve ecological preservation goals. We find that while the financial cost of temporary policy incentives is generally much lower than permanent policy incentives, this difference is very small in scenarios with high discount rates and lower uncertainties in conversion returns and lower expected trend in conservation returns. Alternately, the financial cost of temporary conservation is substantially lower than that of permanent conservation when the expected trend in conservation returns and uncertainties in conservation and conversion returns is high and the discount rate is low. Comparison with net present value and single-source uncertainty models indicates that the presence of a second uncertainty increases the option value of delaying conversion, and shows that permanent and temporary policy incentives based on either of the two simpler models can be seriously misguided if multiple uncertainties are present. We illustrate the analytical results with a case study of tropical deforestation in Indonesia where private landowners can either conserve forests and earn carbon credits, or convert to palm oil agriculture and earn profits from the sale of palm oil.
    Print ISSN: 0002-9092
    Electronic ISSN: 1467-8276
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition , Economics
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 87
    Publication Date: 2016-07-09
    Description: This article analyzes the demand for a simple rainfall-based weather insurance product among farmers in rural India. We explore the predictions of a standard expected utility theory framework on the nature of demand in terms of price, the basis of the hedge, and risk aversion using data from a randomized control trial. We find that demand behaves as predicted: it falls with price and basis risk and is hump-shaped in risk aversion, with price sensitivity decreasing at higher levels of basis risk. We estimate a negative price elasticity of 0.58 and find that doubling the distance to a reference weather station decreases demand by 18%. These results indicate that improving pricing and quality of insurance products can directly increase demand. In addition, we examine the impact of insurance training relative to other mechanisms designed to increase understanding. The evidence suggests that increased incentives to learn or learning by using are more effective at increasing both understanding and demand. Finally, we contribute to the scarce evidence on the demand for insurance over time. In terms of our main interventions, we find that the effect of premium subsidies persists over time, while the impact of investments in new weather stations diminishes and the effect of increased training in the first season seems to disappear during the second season. Importantly, while having previously purchased insurance does not encourage future uptake, receiving a payout does. This could reflect issues of trust in the product or the insurance company, and constitutes an important topic for future research.
    Keywords: D14 - Personal Finance, O12 - Microeconomic Analyses of Economic Development
    Print ISSN: 0002-9092
    Electronic ISSN: 1467-8276
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition , Economics
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 88
    facet.materialart.
    Unknown
    Oxford University Press
    Publication Date: 2016-07-09
    Print ISSN: 0002-9092
    Electronic ISSN: 1467-8276
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition , Economics
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 89
    facet.materialart.
    Unknown
    Oxford University Press
    Publication Date: 2016-07-09
    Print ISSN: 0002-9092
    Electronic ISSN: 1467-8276
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition , Economics
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 90
    Publication Date: 2016-07-09
    Description: Climate change affects agriculture by altering not only output quantity, but also crop quality. We quantify the economic impacts of climate change on agriculture through changes in both quantity and quality, where quality is measured by crop grades. Our model controls for methodological issues regarding sample selection, aggregation, phenology, and nonlinearity. The empirical application to Japanese rice production indicates that temperature effects are asymmetric: quantity is especially vulnerable to cold, whereas quality is vulnerable to extremely high temperature. Using these results, we simulate the effect of global warming, and we find that warming (a 3 °C increase) increases farm revenues by improving yield but decreases revenues as a result of deteriorating quality. The net effect is negative, suggesting that quality matters more than quantity. The negative effect, however, can be mitigated by shifting cultivation periods and/or regions. Overall, our results suggest that the estimated impacts of climate change and adaptation strategies could be severely misleading unless quality is considered.
    Keywords: L15 - Information and Product Quality ; Standardization and Compatibility, Q10 - General, Q54 - Climate ; Natural Disasters ; Global Warming
    Print ISSN: 0002-9092
    Electronic ISSN: 1467-8276
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition , Economics
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 91
    Publication Date: 2016-07-09
    Description: We empirically test four hypotheses regarding differences between agricultural worker earnings (wages and bonuses) during recession and non-recessionary times, between agricultural worker time use during recession and non-recession times, between outcomes for undocumented and documented workers, and between outcomes for agricultural workers versus those working in other sectors of interest. Regression analyses show that the wages of documented (legal) seasonal agricultural workers increased more during the last three recessions than did the wages of undocumented agricultural workers and low-skilled nonagricultural workers. Bonus pay and weekly hours also increased for some workers, suggesting general increases in the financial wellbeing of employed agricultural workers during recessions.
    Keywords: E32 - Business Fluctuations ; Cycles, J43 - Agricultural Labor Markets, J61 - Geographic Labor Mobility ; Immigrant Workers
    Print ISSN: 0002-9092
    Electronic ISSN: 1467-8276
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition , Economics
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 92
    Publication Date: 2016-02-20
    Print ISSN: 0829-318X
    Electronic ISSN: 1758-4469
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 93
    Publication Date: 2016-02-20
    Description: Water deficit associated with drought can severely affect plants and influence ecological interactions involving plant secondary metabolites. We tested the effect of mild water deficit and rewatering on physiological, morphological and chemical traits of juvenile Eucalyptus globulus Labill. and Eucalyptus viminalis Labill. We also tested if responses of juvenile eucalypts to water deficit and rewatering varied within species using provenances across a rainfall gradient. Both species and all provenances were similarly affected by mild water deficit and rewatering, as only foliar abscisic acid levels differed among provenances during water deficit. Across species and provenances, water deficit decreased leaf water potential, above-ground biomass and formylated phloroglucinol compound concentrations, and increased condensed tannin concentrations. Rewatering reduced leaf carbon : nitrogen, and total phenolic and chlorogenic acid concentrations. Water deficit and rewatering had no effect on total oil or individual terpene concentrations. Levels of trait plasticity due to water deficit and rewatering were less than levels of constitutive trait variation among provenances. The overall uniformity of responses to the treatments regardless of native provenance indicates limited diversification of plastic responses when compared with the larger quantitative variation of constitutive traits within these species. These responses to mild water deficit may differ from responses to more extreme water deficit or to responses of juvenile/mature eucalypts growing at each locality.
    Print ISSN: 0829-318X
    Electronic ISSN: 1758-4469
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 94
    Publication Date: 2016-02-20
    Description: Establishing physiological thresholds to drought-induced mortality in a range of plant species is crucial in understanding how plants respond to severe drought. Here, five common European tree species were selected ( Acer campestre L., Acer pseudoplatanus L., Carpinus betulus L., Corylus avellana L. and Fraxinus excelsior L.) to study their hydraulic thresholds to mortality. Photosynthetic parameters during desiccation and the recovery of leaf gas exchange after rewatering were measured. Stem vulnerability curves and leaf pressure–volume curves were investigated to understand the hydraulic coordination of stem and leaf tissue traits. Stem and root samples from well-watered and severely drought-stressed plants of two species were observed using transmission electron microscopy to visualize mortality of cambial cells. The lethal water potential ( lethal ) correlated with stem P 99 (i.e., the xylem water potential at 99% loss of hydraulic conductivity, PLC). However, several plants that were stressed beyond the water potential at 100% PLC showed complete recovery during the next spring, which suggests that the lethal values were underestimated. Moreover, we observed a 1 : 1 relationship between the xylem water potential at the onset of embolism and stomatal closure, confirming hydraulic coordination between leaf and stem tissues. Finally, ultrastructural changes in the cytoplasm of cambium tissue and mortality of cambial cells are proposed to provide an alternative approach to investigate the point of no return associated with plant death.
    Print ISSN: 0829-318X
    Electronic ISSN: 1758-4469
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 95
    Publication Date: 2016-02-20
    Description: We investigated the interspecific variability in nocturnal whole-plant stomatal conductance under well-watered and drought conditions in seedlings of four species of Populus from habitats characterized by abundant water supply (mesic and riparian) or from drier upland sites. The study was carried out to determine whether (i) nocturnal conductance varies across different species of Populus according to their natural habitat, (ii) nocturnal conductance is affected by water stress similarly to daytime conductance based on species habitat and (iii) differences in conductance among species could be explained partly by differences in stomatal traits. We measured whole-plant transpiration and conductance ( G ) of greenhouse-grown seedlings using an automated high-resolution gravimetric technique. No relationship was found between habitat preference and daytime G ( G D ), but night-time G ( G N ) was on average 1.5 times higher in riparian and mesic species ( P. deltoides Bartr. ex Marsh. and P. trichocarpa Torr. & Gray) than in those from drier environments ( P. tremuloides Michx. and P.   x  petrowskyana Schr.). G N was not significantly reduced under drought in riparian species. Upland species restricted G N significantly in response to drought, but it was still at least one order of magnitude greater that the cuticular conductance until leaf death was imminent. Under both well-watered and drought conditions, G N declined with increasing vapour pressure deficit ( D ). Also, a small increase in G N towards the end of the night period was observed in P. deltoides and P.   x  petrowskyana , suggesting the involvement of endogenous regulation. The anatomical analyses indicated a positive correlation between G and variable stomatal pore index among species and revealed that stomata are not likely to be leaky but instead seem capable of complete occlusion, which raises the question of the possible physiological role of the significant G N observed under drought. Further comparisons among closely related species that occupy ecologically diverse habitats may provide a better understanding of the genetic versus environmental regulations of nocturnal water loss.
    Print ISSN: 0829-318X
    Electronic ISSN: 1758-4469
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 96
    Publication Date: 2016-03-02
    Description: There is little information about the impacts of past Sitka spruce ( Picea sitchensis [Bong.] Carr.) tree breeding on wood properties because the emphasis has traditionally been on improving stem form and growth rates. This study used both SilviScan and mechanical testing to investigate the radial variations in wood stiffness, bending strength, density and microfibril angle in defect-free samples taken from the first United Kingdom progeny trial to reach merchantable size. We tested for differences in these radial patterns of variation in half-sibling progeny of three plus trees originally selected for superior growth rate and stem form against a non-selected control. Large differences in all of the properties were observed with radial position, with properties generally being less desirable in the corewood. Significant undesirable differences between the improved families and the control were found for stiffness, strength and microfibril angle. There was no significant relationship between wood density and stiffness in samples taken from the inner part of the tree, where stiffness was more closely associated with microfibril angle. Overall, previous selections for growth rate and/or stem form have compromised timber properties. It is recommended that current breeding programmes focus on corewood stiffness to prevent further degradation in the wood properties of the future timber supply.
    Print ISSN: 0015-752X
    Electronic ISSN: 1464-3626
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 97
    Publication Date: 2016-03-02
    Description: To predict the value of trade between countries, a differential gravity model of bilateral trade flows was formulated and estimated with panel data from 2005 to 2014 for each of the commodity groups HS44 (wood and articles of wood), HS47 (pulp of wood, fibrous cellulosic material) and HS48 (paper and paperboard). The parameters were estimated with a large database by ordinary least squares, fixed-effects and random-effects methods. For the three commodity groups, the results were stable across methods. For HS44, exports were inelastic (0.33 ± 0.19) with respect to the gross domestic product (GDP) of exporters and elastic (1.95 ± 0.15) with the GDP of importers. For HS47, exports were elastic with respect to the exporters GDP (1.67 ± 0.55) and importers GDP (1.10 ± 0.36). Exports of HS48 were inelastic with the exporters GDP (0.81 ± 0.21) and elastic with respect to the importers (1.00 ± 0.14). For all three products, there were marked decreases in exports in 2009 and 2012 independent of GDP. The estimated elasticities were used to predict the growth rate of trade flows from 2015 to 2020 based on exogenous GDP projections of the International Monetary Fund. Another application investigated the effects of the Trans-Pacific Partnership agreement on the trade of forest products between the 12 member countries.
    Print ISSN: 0015-752X
    Electronic ISSN: 1464-3626
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 98
    Publication Date: 2016-03-02
    Description: National forest inventories (NFIs) have to be properly designed in order to yield statistically representative data and make best use of limited resources. A key element to accomplish this is the knowledge of the local variability in the sampled forest stand features. In this study, we estimated the variability of tree taxonomic richness and carbon (C) stock in logged-over and unlogged lowland tropical forests of Papua New Guinea, to define the optimal plot and sample size needed to estimate these characteristics in the context of the forthcoming implementation of the new NFI. We used data from 133 one-hectare permanent sample plots to calculate the coefficient of variation (CV) of C stock and taxonomic richness at different simulated plot sizes. CV was seen to rapidly decrease with increasing plot size up to 0.2–0.3 ha for both features following an inverse-exponential trend. Optimum plot size ranged between 0.08 and 0.32 ha, with 75–164 plots needed to achieve an estimation within 5 per cent of the true mean (95 per cent confidence), depending on the stand feature and the previous silvicultural treatment. We concluded that the establishment of a network of 319 permanent sample plots between 0.2 and 0.3 ha in size would represent an efficient sampling scheme in lowland forests for the new NFI.
    Print ISSN: 0015-752X
    Electronic ISSN: 1464-3626
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 99
    Publication Date: 2016-03-02
    Description: The objective of this study was to compare the utility of combinations of data from airborne laser scanning (ALS), RapidEye satellite imagery and auxiliary environmental data to predict stand structure in a plantation forest. Both parametric and non-parametric modelling techniques that could simultaneously predict a multivariate response were employed and found to produce predictions with similar levels of accuracy. Response variables were derived from 463 field measurement plots that were used during model development; a further 60 randomly selected plots were set aside for validation of model performance. Candidate predictor variables were extracted from the ALS data, satellite data and auxiliary environmental data, and the variables with the greatest explanatory power were used to create six separate models based on combinations of the data sources. Model validation showed that models using RapidEye data only were the least precise and that adding auxiliary environmental data only led to a moderate improvement in model precision. The model precision observed was similar to those reported previously from studies using satellite data to predict stand structure. Models developed using data from ALS were by far the most precise and adding information from satellite data or auxiliary environmental data led to negligible improvement in the prediction of stand structure. Although the outputs of both model types were similar, the practical efficiencies of using the non-parametric approach make it appealing to meet the demands of managers of industrial plantation forest managers.
    Print ISSN: 0015-752X
    Electronic ISSN: 1464-3626
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 100
    Publication Date: 2016-03-02
    Description: The inclusion of quadratic mean diameter (QMD) and relative spacing index (RSI) substantially improved the predictive capacity of height–diameter at breast height (d.b.h.) and crown ratio models (CR), respectively. Data were obtained from 208 permanent plots established in western Arkansas and eastern Oklahoma during 1985–1987 and remeasured for the sixth time (2012–2014). Existing height–d.b.h. and CR estimation models for naturally occurring shortleaf pine forests ( Pinus echinata Mill.) were updated and modified for improved performance. Additionally, eight height–d.b.h. relationship models that use only d.b.h. (fundamental local models) were modified using covariates. The model performance was evaluated using fit statistics [root mean square error (RMSE), Fit index and Akaike information criteria (AIC)]. The results showed that the best model form which was an extended non-linear model with autoregressive first order AR (1) structure and power variance function performed better than extended mixed-effects models and predicted well as an ordinary least squares non-linear model. The autocorrelation within individual trees was larger for the height–d.b.h. relationship than for CR estimation. The addition of QMD to mean dominant height ( H D ) greatly improved height–d.b.h. relationship with a reduction of 8 per cent in RMSE, compared with the use of basal area per hectare . Similarly, multiplying a fundamental local model by using QMD raised to a parametric power reduced RMSE by 16 per cent, improved Fit index by 12 per cent and decreased the AIC value by 7 per cent. D.b.h., H D and RSI best explained the crown ratio relationship with an improved Fit index by 6.7 per cent compared with alternative non-linear models without RSI. The logistic model for CR also provided prediction accuracy similar to that of a commonly used non-linear model. A non-linear model with an application of remedial measures to enhance adherence to modelling assumptions can provide better parameter estimates than mixed-effects modelling approach.
    Print ISSN: 0015-752X
    Electronic ISSN: 1464-3626
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
Close ⊗
This website uses cookies and the analysis tool Matomo. More information can be found here...