ALBERT

Description:    Palaeoclimate proxies have demonstrated links between climate changes and volcanic activity. However, not much is known about the impact of volcanic eruptions on forest productivity. Here we used tree-ring width and annually resolved carbon and oxygen isotopic records from tree rings of Araucaria araucana (Molina) K. Koch, providing a centennial-scale reconstruction of tree ecophysiological processes in forest stands nearby the Lonquimay Volcano (Chile). We observed a mean decrease in tree-ring width following the major eruption of 1988 – 1990 (with aerosol emission), most probably caused by the modified ecological conditions due to acid rain and ash deposition, while a generally negative relationship between δ 13 C and δ 18 O would point to a decline in humidity and precipitation. More negative δ 13 C and lower δ 18 O values (positive correlation) following the major eruption of 1887–1890 (without aerosol emission) would suggest high stomatal conductance and moisture availability, though tree-ring width (and probably photosynthetic rate) was unaltered. At least for this sample of trees, in the case of eruption with large tephra emission, the beneficial effect of aerosol light scattering on tree productivity appears to be outweighed by the detrimental effect of eruption-induced toxic deposition. Signals of the two major eruptions of the past 200 years at Lonquimay were present in tree rings of nearby A. araucana . No unique response of tree functions to volcanic eruptions can be expected, but rather (1) the variable volcanic properties and (2) the complex interplay of diffuse light increase (aerosol scattering), air temperature decrease (cloud shading), and toxic deposition impact (volcanic ash), makes any prediction of tree growth and ecophysiological response very challenging. Content Type Journal Article Category Original Paper Pages 1-15 DOI 10.1007/s00468-012-0749-9 Authors Roberto Tognetti, Dipartimento di Bioscienze e Territorio, Università degli Studi del Molise, Contrada Fonte Lappone, 86090 Pesche, Italy Fabio Lombardi, Dipartimento di Bioscienze e Territorio, Università degli Studi del Molise, Contrada Fonte Lappone, 86090 Pesche, Italy Bruno Lasserre, Dipartimento di Bioscienze e Territorio, Università degli Studi del Molise, Contrada Fonte Lappone, 86090 Pesche, Italy Giovanna Battipaglia, Dipartimento di Scienze Ambientali, Seconda Università di Napoli, Via Vivaldi, 81100 Caserta, Italy Matthias Saurer, PSI, Paul Scherrer Institut, 5232 Villigen, Switzerland Paolo Cherubini, WSL, Swiss Federal Institute for Forest, Snow and Landscape Research, 8903 Birmensdorf, Switzerland Marco Marchetti, Dipartimento di Bioscienze e Territorio, Università degli Studi del Molise, Contrada Fonte Lappone, 86090 Pesche, Italy Journal Trees - Structure and Function Online ISSN 1432-2285 Print ISSN 0931-1890

Description:    We studied the effects of climatic factors on tree-ring width and vessel lumen area (VLA) in earlywood of English oak ( Quercus robur L.) in Latvia. Cores were obtained from healthy canopy oaks in 40 stands located across Latvia. Tree-ring widths and VLA were measured. Principal component analysis was used to arrange the sites along gradients of response of tree-ring width and earlywood to environmental factors. Significant relationships of tree-ring width and mean VLA with climatic factors (mean monthly temperature and precipitation sum) were determined by correlation analysis. Relationships between tree-ring, early- and latewood widths were tested in three sampled stands. The patterns of response of VLA and tree-ring width to environmental factors differed in relation to a west–east gradient of increasing continentality. Three regions of Latvia (western, central and eastern) were distinguished along this gradient. Responses to climate differed between tree-ring width and mean VLA. Occurrence of significant correlations between climatic factors and the proxies differed between regions, likely due to regional differences in temperature and precipitation. Tree-ring width correlated with climatic factors (most commonly with March, May and June temperature and August precipitation of the current growing season and July–August temperatures of the previous growing season); VLA was more strongly related to climatic factors, particularly with temperature in winter and spring months. The proportion of significant correlation coefficients with climatic factors differed between the regions. Among sites, significant correlation of tree-ring width with temperature in spring and summer was more frequent in the western region, while correlation with winter temperature of the previous growing season and precipitation in August was more frequent in the eastern region. For VLA, the frequency of significant correlation coefficients with temperature in winter and spring was higher in the eastern region. Content Type Journal Article Category Original Paper Pages 1-16 DOI 10.1007/s00468-012-0701-z Authors Roberts Matisons, Faculty of Biology, University of Latvia, Kronvalda bulv.4, Riga, LV-1010 Latvia Guntis Brūmelis, Faculty of Biology, University of Latvia, Kronvalda bulv.4, Riga, LV-1010 Latvia Journal Trees - Structure and Function Online ISSN 1432-2285 Print ISSN 0931-1890

Description:    Stem CO 2 efflux ( E S ) is an important component of forest ecosystem carbon budgets and net ecosystem CO 2 exchange, but little is known about E S in temperate forests in Northeastern China, an area with a large extent of forest. We measured E S along with stem temperature at 1 cm depth ( T s) over a 9 month period in 2007 on ten dominant tree species of secondary forests of the region. Other measurements included the autotrophic component of soil CO 2 efflux ( E A ) and stem diameter at breast height (DBH). Our objectives were to (1) examine the seasonal patterns and species differences in E S , and (2) determine the correlations between E S and T s, DBH and E A . Mean E S for the measurement period ranged from 1.09 to 1.74 μmol CO 2  m −2  s −1 among the ten species. The sensitivity of E S to T s ( Q 10 ) ranged from 1.87 to 2.61. Across the ten species 57–89% of variation in E S was explained by T S and DBH. There was also a linear relationship between mean E S and E A . E S was better predicted by T s in the dormant season than the growing season, indicating that additional factors such as growth respiration and internal transport of CO 2 in the xylem became more important contributors to E S during the growing season. Stem CO 2 efflux increased, and Q 10 decreased, with increasing DBH in all species. Although temperature exerts strong control on the rate of cellular respiration, we conclude that in tree stems in situ, T S , DBH and many other factors affect the relationship between CO 2 evolution by respiring cells and the diffusion of CO 2 to the stem surface. Content Type Journal Article Category Original Paper Pages 1-11 DOI 10.1007/s00468-012-0698-3 Authors J. Y. Yang, Center for Ecological Research, Northeast Forestry University, Harbin, 150040 China R. O. Teskey, Warnell School of Forestry and Natural Resources, University of Georgia, Athens, 30602 USA C. K. Wang, Center for Ecological Research, Northeast Forestry University, Harbin, 150040 China Journal Trees - Structure and Function Online ISSN 1432-2285 Print ISSN 0931-1890

Description:    We analyzed the leaf phenology of European beech ( Fagus sylvatica ) and its variation due to spatial and temporal climatic variability, using a modified data set of the phenological network in Slovenia. We used first leaf unfolding (LU) and general leaf colouring (LC) time series of 47 sites (altitudes from 55 to 1,050 m a.s.l.) and corresponding climate series (52 of precipitation and 38 of temperature) for the period 1955–2007, collected by the Environmental Agency of the Republic of Slovenia. Across the network in average, LU occurred from 14 April until 13 May, and LC from 3 October until 29 October. LU was delayed by 2.6 days and LC was promoted by 1.9 days when the altitude increased by 100 m. Year-to-year variation of LU was significantly correlated with March and April temperatures. March temperatures had a greater effect at lower elevations and April ones at higher elevations. LC was related to August and September temperatures, and occurred later if the temperatures were higher. Recently, March and April temperatures showed an increasing trend and LU occurred 1.52 days earlier per decade at 1,000 m a.s.l. but no significant shifts were observed at lower altitudes. August temperatures were also increasing but the trends of LC were not significant and were not clearly related to altitude. Our detailed sub-regional data from a relatively small area with high geographic variability showed that changes in climate affect phenological response, mainly leaf unfolding, to a greater degree at higher altitudes than at lower ones. Content Type Journal Article Category Original Paper Pages 1-10 DOI 10.1007/s00468-012-0686-7 Authors Katarina Čufar, Department of Wood Science and Technology, Biotechnical Faculty, University of Ljubljana, Rožna Dolina, Cesta VIII/34, 1000 Ljubljana, Slovenia Martin De Luis, Department of Geography, University of Zaragoza, y O.T. C/Pedro Cerbuna 12, 50009 Zaragoza, Spain Miguel Angel Saz, Department of Geography, University of Zaragoza, y O.T. C/Pedro Cerbuna 12, 50009 Zaragoza, Spain Zalika Črepinšek, Agronomy Department, Biotechnical Faculty, University of Ljubljana, Jamnikarjeva 101, 1000 Ljubljana, Slovenia Lučka Kajfež-Bogataj, Agronomy Department, Biotechnical Faculty, University of Ljubljana, Jamnikarjeva 101, 1000 Ljubljana, Slovenia Journal Trees - Structure and Function Online ISSN 1432-2285 Print ISSN 0931-1890

Description:    Tsuga canadensis is often considered a foundation species because of its influence on the biological and ecological processes of upland forest systems. With hemlock woolly adelgid ( Adelges tsugae ; HWA)-induced mortality of T. canadensis in southern Appalachian upland forests, there is a crucial need to understand the regeneration dynamics of this tree species. This research was conducted within mature T. canadensis forests of Great Smoky Mountains National Park (GSMNP) prior to widespread HWA infestation. Tsuga canadensis regeneration abundance is lower than has been reported in more northern locales, but varies widely among sites in the southern Appalachian Mountains. Ordination results suggest landscape-scale patterns of regeneration abundance that are influenced by gradients in understory Rhododendron maximum cover, soil sand and nutrient content. Regression models reinforce the observed gradients in regeneration abundance. Sites with abundant T. canadensis regeneration have less R. maximum cover, soil sand and litter depth, but more soil nutrient availability. Tsuga canadensis seedlings and saplings tend to be spatially aggregated at the 14 × 21 m plot scale. Sites with spatially aggregated seedlings and saplings have greater canopy openness and more species with gap affinity. This research elucidates associations between successful T. canadensis regeneration and site factors such as soil nutrient availability and canopy dynamics. More forest surveys are required to understand the conditions necessary for successful T. canadensis regeneration. Land managers involved in forest restoration efforts may have to utilize appropriate silvicultural techniques conjoined with R. maximum removal operations to regenerate T. canadensis in southern Appalachian upland forests. Content Type Journal Article Category Original Paper Pages 1-12 DOI 10.1007/s00468-012-0681-z Authors Joshua A. Kincaid, Environmental Studies Department, Shenandoah University, 1460 University Drive, Winchester, VA 22601, USA Journal Trees - Structure and Function Online ISSN 1432-2285 Print ISSN 0931-1890

Description:    To contribute to a deeper understanding of interspecific relations between wood and tree size variables, 23 angiosperm tree species in two East African rain forests were investigated. The tree size variables were maximum tree height, maximum diameter, and maximum crown area. Wood was analyzed in regard of the physical variables specific gravity, water and gas fraction as well as the chemical variables carbon content and nitrogen content. All three tree size variables showed a significantly positive relation to each other. The wood physical variables showed negative correlations between the gas fraction and both specific gravity and the water fraction. Also positive relations were found between the water fraction and nitrogen content and between wood specific gravity and carbon content. Between tree size and wood physical variables, the gas fraction showed positive relations to both maximum tree height and diameter, while wood specific gravity was negatively related to maximum tree height and diameter. No significant correlations were found between the wood physical variables and the maximum crown area. Relationships among tree size variables can be explained by static constraints, while relations between the wood physical variables can be explained by a trade-off underlying structure and survival to support the species specific life strategy and tree architecture. Content Type Journal Article Category Original Paper Pages 1-12 DOI 10.1007/s00468-012-0687-6 Authors Gabriel Sebastian Becker, Institute of Botany, University of Hohenheim, Garbenstrasse 30, 70599 Stuttgart, Germany Désirée Braun, Institute of Botany, University of Hohenheim, Garbenstrasse 30, 70599 Stuttgart, Germany Robert Gliniars, Institute of Botany, University of Hohenheim, Garbenstrasse 30, 70599 Stuttgart, Germany Helmut Dalitz, Institute of Botany, University of Hohenheim, Garbenstrasse 30, 70599 Stuttgart, Germany Journal Trees - Structure and Function Online ISSN 1432-2285 Print ISSN 0931-1890

Description:    Afforestation and reforestation activities enjoy a prominent place on the policy agenda as potential tools to sequester carbon and for biomass production to mitigate climate change and restoring marginal lands. Two provenances (1 from Turkey and 1 from Lebanon) of the species Cedrus libani A. Rich. and two provenances (1 from Morocco and 1 from France) of the species Cedrus atlantica (Endl.) Carrier were studied to evaluate to what degree these trees were suitable for afforestation in arid regions of Italy. We measured, seasonal stomatal conductance ( g s ), foliar morphology, foliar carbon isotopic composition (δ 13 C), growth, and assessed bud phenology in a split plot trials. Bud phenology showed that the Turkish and Lebanon provenances of C. libani gave rise to earlier buds (earlier bud provenances) than the Moroccan and French provenances of C. atlantica (later bud provenances) with a mean difference of 23.2 days. Both provenances showed similar bud phenology and seasonal stomatal conductance ( g s ) especially in April–May (earlier bud provenances) and June (later bud provenances). The foliar δ 13 C was negatively correlated with g s in both the earlier bud provenances (i.e., an increase in g s was accompanied by decreasing foliar δ 13 C values) and the later bud provenances. The stomatal conductance values measured over a growth season showed significant correlations with daily means of both temperature and relative humidity. Hence g s in the earlier bud provenances was correlated with daily temperature in spring, whereas correlations with relative humidity were found in later bud provenances in both late spring and summer. We concluded that the earlier bud provenances ( C. libani ) are not suitable in areas affected by both summer drought and late spring frosts, whereas the later bud provenances ( C. atlantica ) are more suitable to be used in future afforestation plans due to their greater tolerance to summer drought. Content Type Journal Article Category Original Paper Pages 1-7 DOI 10.1007/s00468-012-0692-9 Authors Giovanni di Matteo, CRA-PLF, Agricultural Research Council, Research Unit for Wood Production Outside Forests, Via Valle della Quistione 27, 00166 Rome, Italy Marco Riccardi, CRA-PLF, Agricultural Research Council, Research Unit for Wood Production Outside Forests, Via Valle della Quistione 27, 00166 Rome, Italy Francesco Righi, CRA-PLF, Agricultural Research Council, Research Unit for Wood Production Outside Forests, Via Valle della Quistione 27, 00166 Rome, Italy Ernesto Fusaro, CRA-PLF, Agricultural Research Council, Research Unit for Wood Production Outside Forests, Via Valle della Quistione 27, 00166 Rome, Italy Journal Trees - Structure and Function Online ISSN 1432-2285 Print ISSN 0931-1890

Description:    Fingered citron ( Citrus medica L. var. sarcodactylis Swingle), a precious fruit ornamental plant, is sensitive to low temperature. Cold tolerance, evaluated by semi-lethal temperature, was lower in wild-type ‘Qingpi’ than in its mutant ‘Aihua’ trees obtained by γ-radiation. The full-length cDNAs of two genes encoding fatty acid desaturases involved in unsaturated fatty acid biosynthesis were isolated from the fingered citron leaves. The CmsFAD2 open reading frame (ORF) had 1,152 bp and was uninterrupted, encoding a polypeptide of 384 amino acids that showing 82% homology with the microsomal ω-6 desaturase CiFAD2 in Davidia involucrate . The CmsFAD8 ORF contained 1,373 bp and 7 introns, encoding a polypeptide of 458 amino acids showing 76% homology with the plastidial ω-3 desaturase BpFAD8 in Betula pendula . CmsFAD2 was expressed highly in leaves but low in roots and flowers, while CmsFAD8 was obviously expressed in three tissues. Compared with control group (28°C), the expression of CmsFAD2 and CmsFAD8 in leaves of two genotypes was significantly induced at 6°C. The increase of CmsFAD2 and CmsFAD8 was earlier and larger in cold-tolerant ‘Aihua’ than in cold-sensitive ‘Qingpi’. The linolenic acid content increased significantly in leaves of mutant ‘Aihua’ plants exposed to low temperature of 6°C. The results showed that a positive relationship between CmsFAD expression and genotype tolerance to cold may exist. Content Type Journal Article Category Original Paper Pages 1-9 DOI 10.1007/s00468-012-0695-6 Authors Ling Yang, College of Chemistry and Life Sciences, Zhejiang Normal University, Jinhua, 321004 Zhejiang, China Jin Ye, College of Chemistry and Life Sciences, Zhejiang Normal University, Jinhua, 321004 Zhejiang, China Wei-Dong Guo, College of Chemistry and Life Sciences, Zhejiang Normal University, Jinhua, 321004 Zhejiang, China Chang-Chun Wang, College of Chemistry and Life Sciences, Zhejiang Normal University, Jinhua, 321004 Zhejiang, China Hai-Tao Hu, College of Chemistry and Life Sciences, Zhejiang Normal University, Jinhua, 321004 Zhejiang, China Journal Trees - Structure and Function Online ISSN 1432-2285 Print ISSN 0931-1890

Description:    Leaf gas-exchange, leaf and shoot anatomy, wood density and hydraulic conductivity were investigated in seedlings of Quercus suber L. grown for 15 months either at elevated (700 μmol mol −1 ) or normal (350 μmol mol −1 ) ambient atmospheric CO 2 concentrations. Plants were grown in greenhouses in a controlled environment: relative humidity 50% (±5), temperature similar to external temperature and natural light conditions. Plants were supplied with nutrients and two water regimes (WW, well watered; WS, water stress). After 6 months exposure to CO 2 enrichment an increase in photosynthetic rate, a decrease in stomatal conductance and a decrease in carbon isotope discrimination (Δ 13 C) were observed, along with enhanced growth and an increase in the number of branches and branch diameter. Over the same period, the shoot weight ratio increased, the root weight ratio decreased and the leaf weight ratio was unaffected. The specific leaf area increased due to an increase in total leaf thickness, mainly due to the palisade parenchyma and starch. However, after 9 and 15 months of elevated CO 2 exposure, the above-mentioned physiological and morphological parameters appeared to be unaffected. Elevated CO 2 did not promote changes in vessel lumen diameter, vessel frequency or wood density in stems grown in greenhouse conditions. As a consequence, xylem hydraulic efficiency remained unchanged. Likewise, xylem vulnerability to embolism was not modified by elevated CO 2 . In summary, elevated CO 2 had no positive effect on the ecophysiological parameters or growth of water stressed plants. Content Type Journal Article Category Original Paper Pages 1-13 DOI 10.1007/s00468-012-0691-x Authors M. Vaz, Departamento de Biologia, Instituto de Ciências Agrárias e Ambientais Mediterrânicas (ICAAM), Universidade de Évora, Apartado 94, 7002-554 Évora, Portugal H. Cochard, INRA, UMR 547 PIAF, 63100 Clermont-Ferrand, France L. Gazarini, Departamento de Biologia, Instituto de Ciências Agrárias e Ambientais Mediterrânicas (ICAAM), Universidade de Évora, Apartado 94, 7002-554 Évora, Portugal J. Graça, Instituto Superior de Agronomia, Universidade Técnica de Lisboa, Tapada da Ajuda, 1349-017 Lisbon, Portugal M. M. Chaves, Instituto Superior de Agronomia, Universidade Técnica de Lisboa, Tapada da Ajuda, 1349-017 Lisbon, Portugal J. S. Pereira, Instituto Superior de Agronomia, Universidade Técnica de Lisboa, Tapada da Ajuda, 1349-017 Lisbon, Portugal Journal Trees - Structure and Function Online ISSN 1432-2285 Print ISSN 0931-1890

Description:    The effect of stone dust deposition on the rate of transpiration in Shorea robusta was studied in three principal seasons in a polluted forest in comparison to an almost non-polluted forest. The extent of particulate pollution was determined by measuring suspended particulate matter in the air and dust fall on leaf surface. Macroscopic and microscopic leaf injury symptoms were studied. Scanning electron microscopic examination of leaf surfaces revealed a number of foliar anomalies. Qualitative determination of rate of transpiration in field condition was done by ‘cobalt chloride method’. It was found that transpiration was diminished as a result of foliar dust deposition which not only caused blockage of stomatal aperture but also physical damage to the leaf surface. Thus, particulate air pollution can be considered as one of the external factors regulating the rate of transpiration in plants. Content Type Journal Article Category Original Paper Pages 1-9 DOI 10.1007/s00468-012-0697-4 Authors Dulal C. Saha, Centre for Environmental Studies, Institute of Science, Visva-Bharati University, Santiniketan, 731235 India Pratap K. Padhy, Centre for Environmental Studies, Institute of Science, Visva-Bharati University, Santiniketan, 731235 India Journal Trees - Structure and Function Online ISSN 1432-2285 Print ISSN 0931-1890