ALBERT

Description: Handroanthus impetiginosus, pink lapacho, is a timber, ornamental, and medicinal tree. Experiments on the in vitro propagation of H. impetiginosus were conducted using nodal segments cultivated in both Murashige and Skoog salts with Gamborg vitamins (MSG) and Woody Plant Medium (WPM) with different concentrations of 6-benzylaminopurine (BA) and indole butyric acid (IBA). Morphogenic responses were differentially affected by salt compositions and their interactions with plant growth regulators in each micropropagation stage. According to response surface analysis, the optimum multiplication rate with 1 μM IBA ranged from 16.7 to 21.3 μM BA in WPM, and the inhibitors of endogenous auxins could increase multiplication rates. A pulse with 50 μM IBA in 1/2 MSG produced 83% rooting with 3.2 roots per shoots and higher fresh and dry weights of shoots and roots. In the acclimatisation stage, 50% of plants survived after 1 year. This methodology optimised the culture media for the in vitro propagation of the H. impetiginosus clonal pool and could be applied to related species, several of which are categorised as vulnerable on the International Union for the Conservation of Nature Red List.

Description: We tested the hypothesis that changes in leaf area index (LAI m2 m−2) and mean stand diameter following thinning are due to thinning type and residual density. The ratios of pre- to postthinning diameter and LAI were used to assess structural changes between replicated crown, dominant, and low thinning treatments to 33% and 50% residual density in even-aged Picea rubens and Abies balsamea stands with and without a precommercial thinning history in Maine, USA. Diameter ratios varied predictably by thinning type: low thinnings were <0.7, crown thinnings were >0.7 but <1.0, and dominant thinnings were >1.0 . LAI change was affected by type and intensity of thinning. On average, 33% density reduction removed <50% of LAI, whereas 50% density reduction removed >50% of LAI. Overall reduction of LAI was generally greatest in dominant thinnings (54%), intermediate in crown thinnings (46%), and lowest in low thinnings (35%). Upon closer examination by crown classes, the postthinning distribution of LAI between upper and lower crown classes varied by thinning history, thinning method, and amount of density reduction.

Description: Forest ecosystem dynamics are driven by a complex array of simultaneous cause-and-effect relationships. Understanding this complex web requires specialized analytical techniques such as Structural Equation Modeling (SEM). The SEM framework and implementation steps are outlined in this study, and we then demonstrate the technique by application to overstory-understory relationships in mature Douglas-fir forests in the northwestern USA. A SEM model was formulated with (1) a path model representing the effects of successively higher layers of vegetation on late-seral herbs through processes such as light attenuation and (2) a measurement model accounting for measurement errors. The fitted SEM model suggested a direct negative effect of light attenuation on late-seral herbs cover but a direct positive effect of northern aspect. Moreover, many processes have indirect effects mediated through midstory vegetation. SEM is recommended as a forest management tool for designing silvicultural treatments and systems for attaining complex arrays of management objectives.

Description: This study focuses on the influence of the 2008 ice storm in China and subsequent forest rehabilitation dynamics up until 2011. All seven plots studied exhibited significant damage, with the total number of damaged trees varying between 63 and 92%. In addition, most trees suffered stem bending in 2008 and the extent of damage varied with tree diameter at breast high (DBH). Relationships between loss of biomass as dead trees and stand characteristics were analyzed by multiple stepwise regression. The results showed that the decrease in biomass (Y) could be related to altitude (X1), slope (X2), and aboveground biomass (AGB) in 2008 (X5) according to the following formula:

Description: Moroni et al. (2012) made forty claims which misrepresent my earlier reply to their work (Dean, 2011) and if left unrefuted, might mislead all but the most expert reader—I cover seven of the most important ones here. Firstly, in my earlier paper I had calculated a conservative carbon deficit in State forests due to logging of the most-targeted forest types—mature wet-eucalypt—by clearfell, burn and sow to yield even-aged eucalypt regeneration. That deficit was conservative as a range of stand ages were used even though most carbon flux through logging has been from the old-growth subset. It was additionally conservative at the landscape-scale as inclusion of conversion to plantation and logging of other primary-forest types would have yielded a larger carbon deficit, not a smaller one, as implied in Moroni et al. (2012). Secondly, their claim that I applied “carbon saturation” at the landscape-scale is incorrect. Instead I applied carbon carrying capacity at that scale and included different stands ages in its calculation (by definition). Conversely, Moroni et al. (2012) produce the “confusion” which they claim to observe by advocating the use of “carbon saturation” at the landscape-scale, which can have no practical usage.

Description: Estimation of forest carbon storage can be of great significance to the research on the productivity of terrestrial ecosystem, carbon cycle, and global warming. China has more than 54 million hm2 barren hills and waste land suitable for forestation, which provides a great potential for developing carbon sink forestry by means of forestation. This research analyzed the volume increments, volume densities, and carbon contents of 15 analytical samples of five main plantation tree species in North China, including Pinus tabulaeformis (A), Robinia pseudoacacia (B), Populus euramericana (C), Larix olgenisis (D), and Larix kaempferi (E). Results showed that carbon storage dynamic process can be expressed as follows: the ages of quantitative maturity of each tree species are 67a, 40a, 30a, 48a, 49a, respectively; the average wood densities of each tree species at different age classes are 550.93 kg/m3, 629.25 kg/m3, 404.56 kg/m3, 592.33 kg/m3, and 544.11 kg/m3,t. The average carbon contents of each tree species at different age classes are 51.48%, 46.88%, 47.81%, 46.76%, and 47.24%. It showed a significant difference between the above tree species through variance test. The maximum values of average carbon storage are 70a, 40a, 30a, 48.7a, and 49.2a, respectively. The corresponding average carbon storages are A 2.527 kg, B 3,794 kg, C 2.781 kg, D 2.996 kg, and E 3,322 kg, in a descending order of C>E>D>B>A. This research, through experiment on four tree species with clear growth rings and one tree species with unclear growth rings, verified the scientific character and the scope of application of the carbon storage dynamic analysis method, providing a new method for the measurement and analysis of forest carbon storage.

Description: Forest cover dynamics (defined as tree canopy cover change without regard to forest land use) within the Russian European North have been analyzed from 1990 to 2005 using a combination of results from two Landsat-based forest cover monitoring projects: 1990–2000 and 2000–2005. Results of the forest cover dynamics analysis highlighted several trends in forest cover change since the breakdown of the Soviet planned economy. While total logging area decreased from the 1990–2000 to the 2000–2005 interval, logging and other forms of anthropogenically-induced clearing increased within the Central and Western parts of the region. The most populated regions of European Russia featured the highest rates of net forest cover loss. Our results also revealed intensive gross forest cover loss due to forest felling close to the Russian-Finland border. The annual burned forest area almost doubled between the two time intervals. The 2000–2005 gross forest cover gain results suggest that tree encroachment on abandoned agriculture land is a wide-spread process over the region. The analysis demonstrates the value of regional-scale Landsat-based forest cover and change quantification. Our results supplemented official data by providing independently derived spatial information that could be used for assessing on-going trends and serve as a baseline for future forest cover monitoring.

Description: Snags provide important biological legacies, resources for numerous species of native wildlife, and contribute to decay dynamics and ecological processes in forested ecosystems. We monitored trends in snag populations from 1997 to 2007 in drought-stressed mixed-conifer and ponderosa pine (Pinus ponderosa Dougl. ex Laws) forests, northern Arizona. Median snag density increased by 75 and 90% in mixed-conifer and ponderosa pine forests, respectively, over this time period. Increased snag density was driven primarily by a large pulse in drought-mediated tree mortality from 2002 to 2007, following a smaller pulse from 1997 to 2002. Decay-class composition and size-class composition of snag populations changed in both forest types, and species composition changed in mixed-conifer forest. Increases in snag abundance may benefit some species of native wildlife in the short-term by providing increased foraging and nesting resources, but these increases may be unsustainable in the long term. Observed changes in snag recruitment and fall rates during the study illustrate the difficulty involved in modeling dynamics of those populations in an era of climate change and changing land management practices.

Description: The population of shea butter tree (Vitellaria paradoxa C. F. Gaertn.)—a priority tree with enormous economic and cultural values to the parkland communities in Uganda, is rapidly declining due to rapid human population growth, increasing land fragmentation, and high demand for woodfuel especially charcoal. Reversing this trend will depend on the rural community involvement in the planting, facilitating natural regeneration, and tending of shea trees on farm. As such a survey was conducted in Amuria district, eastern Uganda, to assess local strategies and constraints to on-farm management of shea trees, and document socio-demographic factors influencing the on-farm conservation. About 93% of the households protected naturally regenerated V. paradoxa trees mainly on farms. V. paradoxa was mostly propagated through coppices and seedlings. Although insecure land tenure, insecurity, pests, disease, and shortage of planting materials were reported as major hindrances, farmsize, family size, and gender significantly (P≤0.05) influenced people’s willingness to conserve V. paradoxa. Byelaws and policies on shea conservation need to be properly enforced, and further propagation research is required especially towards shortening the juvenile period of V. paradoxa so that more farmers can start propagating the tree other than relying on its natural regeneration.