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1.
María Pasalodos-Tato Timo Pukkala Isabel Cañellas Mariola Sánchez-González 《Annals of Forest Science》2018,75(2):61
Key message
Optimal management of cork oak forest stands was analyzed for different site indices and cork growth rates. Optimal debarking intervals varied during the rotation and were sometimes shorter or longer than the officially recommended range of 9–14 years.Context
Quercus suber L. is one of the most important multipurpose tree species in the Mediterranean area. Its main product is cork, appreciated for its elasticity, impermeability, and thermal insulation properties. Cork oaks are debarked at constant intervals, which vary from 9 to 14 years depending on the area. However, since the growth rate of cork is not constant during the rotation, it may be optimal to use variable debarking intervals.Aims
This study optimized the debarking and cutting schedules of Quercus suber stands and analyzed the influence of economic and stand-related factors on optimal management.Methods
The study employed a simulation system where the existing growth and yield models for Quercus suber were used with a non-linear derivative-free optimization algorithm. Discount rates and cork prices were tested as economic factors and cork growth rate and site productivity as stand-related factors.Results
The optimal debarking interval varied during the rotation. Increasing cork growth rate increased the optimal number of debarkings and shortened their interval. Decreasing discount rate increased the optimal number of debarkings during rotation while decreasing cork price decreased the number of debarkings.Conclusion
The profitability of the management of cork oak stands depends on site fertility and stand density; management is not profitable on poor sites or at high discount rates. This study is the first that simultaneously optimizes the cutting and debarking schedule of cork oak stands, allowing the debarking interval to vary.2.
Giovânia C. Araújo Nadine R. Sousa Miguel A. Ramos Alberto L. Vega Paula M. L. Castro 《Annals of Forest Science》2018,75(1):29
Key message
Despite the fact that the technique of application of bioinoculants improved the quality of Quercus suber L. seedlings produced in nurseries, these benefits are dependent on the ecological conditions of the site and the composition of the applied inoculum, which interferes with the profile of the local fungal community.Context
Quercus suber L. plays a key ecological and socio-economical role in the Iberian Peninsula. Symbiotic ectomycorrhizal fungi-ECM are crucial partners of several tree species, and assessing the efficacy of bioinoculants at nursery stage helps devising tools to increase plant resilience.Aims
The aim of this study was to compare the effects of two inocula formulations of mixed ECM fungi and bacteria on the quality of seedlings produced in two forest nurseries, differing in environmental conditions and forest embedment.Methods
Quercus suber L. seedlings were inoculated with a commercial product containing Pisolithus tinctorius (Pers) Coker & Couch, Scleroderma sp., and six bacterial species and with a non-commercial fungal and bacterial dual inoculum (Suillus granulatus (L.) Roussel + Mesorhizobium sp.). Biometric and nutritional parameters and morphological quality indexes were determined on seedlings. The ECM community was assessed by denaturing gradient gel electrophoresis and cloning-sequencing.Results
In both nurseries, the seedling quality index in inoculated was up to 2-fold higher than in non-inoculated seedlings. Plant biomass differed significantly among nurseries. The inoculum influenced the profile of the fungal community. S. granulatus and P. tinctorius persisted for 6 months in the inoculated seedlings.Conclusion
The nursery ecosystem influenced plant growth. Inoculation treatments increased plant performance; however, the dual inoculum resulted in more consistent improvements of Q. suber at nursery stage, highlighting the importance of inocula selection.3.
Yuan Liu Yuejuan Li Jialin Song Ruipu Zhang Yu Yan Yuyao Wang Fang K. Du 《Annals of Forest Science》2018,75(4):90
Key message
Geometric morphometric analyses (GMMs) of the leaf shape can distinguish two congeneric oak species Quercus dentata Thunberg and Quercus aliena Blume in sympatric areas.Contexts
High genetic and morphological variation in different Quercus species hinder efforts to distinguish them. In China, Q. dentata and Q. aliena are generally sympatrically distributed in warm temperate forests, and share some leaf morphological characteristics.Aims
The aim of this study was to use the morphometric methods to discriminate these sympatric Chinese oaks preliminarily identified from molecular markers.Methods
Three hundred sixty-seven trees of seven sympatric Q. dentata and Q. aliena populations were genetically assigned to one of the two species or hybrids using Bayesian clustering analysis based on nSSR. This grouping served as a priori classification of the trees. Shapes of 1835 leaves from the 367 trees were analyzed in terms of 13 characters (landmarks) by GMMs. Correlations between environmental and leaf morphology parameters were studied using linear regression analyses.Results
The two species were efficiently discriminated by the leaf morphology analyses (96.9 and 95.9% of sampled Q. aliena trees and Q. dentata trees were correctly identified), while putative hybrids between the two species were found to be morphologically intermediate. Moreover, we demonstrated that the leaf morphological variations of Q. aliena, Q. dentata, and their putative hybrids are correlated with environmental factors, possibly because the variation of leaf morphology is part of the response to different habitats and environmental disturbances.Conclusion
GMMs were able to correctly classify individuals from the two species preliminary identified as Q. dentata or Q. aliena by nSSR. The high degree of classification accuracy provided by this approach may be exploited to discriminate other problematic species and highlight its utility in plant ecology and evolution studies.4.
Key message
The use of increasing debarking during the first harvest of cork oak trees ( Quercus suber L.) had no effect on the secondary cork calliper (thickness) in one of the trials and had a small negative effect in a second trial. Little evidence was found that debarking coefficient is a useful index for the management of cork oak stands.Context
The Portuguese national legislation defines, without the support of scientific data or knowledge, maximum values of debarking coefficients (ratio of debarking height and perimeter at breast height measured over cork). For the first debarking, this value is limited to 2.0.Aims
The aim of this study was to determine the impact of increasing cork debarking coefficient on the calliper of the secondary cork extraction.Methods
Trees were located in two sites, in distinct regions characterized by low or high productivity classes. Three debarking coefficients were considered: 1.5, 2.0 and 2.5. The debarking coefficient for the first cork extraction was randomly selected for each tree. During the second debarking, a cork sample was taken from each tree. The samples were used for assessing secondary cork calliper. Differences in cork calliper were analysed using both correlation analysis and modelling approaches.Results
Debarking intensity increase had a small negative effect on secondary cork thickness in the most inland site, while no effect was detected in the more coastal site.Conclusion
In our experiment, debarking intensity had a significant but small effect in one site and no effect in other sites. Debarking coefficients not only should be defined according to legal constraints but also instead should be adapted considering tree and site characteristics.5.
Key message
In the African rim of the Western Mediterranean Basin, cork oak forests and pine plantations coexist. Under similar fire regimes, cork oak forest is more resilient in terms of habitat structure (canopy, understory, and complexity of vegetation strata) than pine plantation. By contrast, both woodland types show similar resilience in plant species composition. Resilience in habitat structure varies between the two woodland types because of the resprouting and seeding strategies of cork oak and pine species, respectively. These differences can be relevant for the conservation of biodiversity of forested ecosystems in a future scenario of increased fire frequency and scale in the Mediterranean basin.Context
Wildfires have major impacts on ecosystems globally. In fire-prone regions, plant species have developed adaptive traits (resprouting and seeding) to survive and persist due to long evolutionary coexistence with fire. In the African rim of the Western Mediterranean Basin, cork oak forest and pine plantation are the most frequently burnt woodlands. Both species have different strategies to respond fire: cork oak is a resprouter while pines are mostly seeders.Aims
We have examined the hypothesis that pine plantations are less resilient in habitat structure (canopy, understory, diversity of vegetation strata) and plant composition than cork oak woodlands.Methods
The habitat structure and plant species composition were measured in 30 burnt and 30 unburnt 700-m transects at 12 burnt sites from north-western Africa, where the two forest types can coexist. Habitat structure and plant species composition were compared between burnt and unburnt transects from cork oak and pine plantation woodlands with generalized linear mixed models and general linear models.Results
The results showed significant interaction effect of fire and forest type, since cork oak forest was more resilient to fire than was pine plantation in habitat structure. By contrast, both forest types were resilient to fire in the composition of the plant communities, i.e., plant composition prior to fire did not change afterwards.Conclusion
The higher structural resilience of cork oak forest compared to pine plantation is related to the resprouting and seeding strategies, respectively, of the dominant tree species. Differences in the responses to fire need to be considered in conservation planning for the maintenance of the Mediterranean biodiversity in a future scenario of changes in fire regime.6.
Fernando Silla Álvaro Camisón Andrea Solana Héctor Hernández Guillermo Ríos Miguel Cabrera Dámaris López Albert Morera-Beita 《Annals of Forest Science》2018,75(4):95
Key message
Quercus secondary forests show a gradual transition toward mixed forests, with sweet chestnut ( Castanea sativa ) becoming increasingly abundant in the western Spanish Central System. Additionally, in chestnut-dominated stands, it shows a certain resistance to competitive displacement by Quercus pyrenaica . Our results partially refute the traditional view that C. sativa is unable to recruit in the absence of cultural inputs.Context
Sweet chestnut, Castanea sativa, is a component of European broadleaf forests and is one of the most managed trees. Due to a reduction in cultural inputs, chestnut-dominated stands tend to be invaded by other species, and it is unclear how chestnut is able to persist in natural mixed forests.Aims
Our work aimed to identity the main factors that limit the establishment of C. sativa and to analyze the recruitment and mortality processes of C. sativa trees.Methods
The age, growth ring patterns, regeneration density, and the spatial structure of trees and saplings in 11 plots in the Spanish Central System were analyzed.Results
Chestnut seedling density increased with C. sativa basal area, but transition toward the sapling stage appeared limited owing to light availability. In Quercus pyrenaica secondary forests, sparse canopies did not constrain chestnut regeneration, and in old chestnut stands, C. sativa showed a certain resistance to competitive displacement. By contrast, mixed young coppices showed a high mortality, most likely due to competition with other vigorous resprouters.Conclusion
Quercus secondary forests showed a gradual transition toward mixed forests with sweet chestnut becoming increasingly more abundant. In old stands, C. sativa is likely to persist under a gap-phase mode of regeneration. Our results partially refute the traditional view that C. sativa is unable to recruit in the absence of cultural inputs.7.
Joanna Mucha Andrzej M. Jagodziński Bartosz Bułaj Piotr Łakomy Adrian M. Talaśka Jacek Oleksyn Marcin Zadworny 《Annals of Forest Science》2018,75(1):22
Key message
Quercus robur seedling mass was affected more by planting density than by taproot pruning. Root pruning enhanced stem biomass at the expense of roots in later growth stages. Alteration of biomass allocation due to nursery practices may result in greater susceptibility to injury and death of the seedlings under unfavorable environmental conditions.Context
Plants adjust their growth and modulate the resource allocation in response to applied treatments and environmental conditions.Aims
The aim was to examine how taproot pruning in seedlings grown at different densities affected long-term growth of Quercus robur.Methods
Seedlings, sown as acorns at two planting densities, with or without pruned roots were harvested in the second, fourth, and fifth years of growth. The effect of root pruning on biomass allocation was determined by measuring leaf, stem, and root mass fractions; carbohydrate concentrations in the roots; and C/N ratios. Specific leaf area and root length were also determined to assess morphological adaptations to growth conditions.Results
Total seedling mass was affected more by planting density than by taproot pruning. After 4 years of growth, root mass fractions were lower and stem mass fractions were greater in seedlings planted at a higher density. Five-year old root-pruned seedlings also had a lower root mass fraction and higher stem mass fractions than unpruned seedlings. Specific root length was not affected by root pruning or planting density.Conclusion
Decrease of relative root biomass with simultaneous increase of stem biomass may be a long-term consequence of taproot pruning of Q. robur, and the effects may manifest years after the seedling stage.8.
María Menéndez-Gutiérrez Margarita Alonso Gabriel Toval Raquel Díaz 《Annals of Forest Science》2017,74(4):76
Key message
Pinus pinaster Ait. susceptibility to pinewood nematode significantly differed among provenances, and the two Atlantic provenances of the Iberian Peninsula being the most affected. However, significant provenance × environment interaction was found. Provenance susceptibility was related to basal diameter, number of branches and oleoresin flow, and some climatic parameters.Context
The pinewood nematode Bursaphelenchus xylophilus, native to North America, is an important pest affecting pine forests throughout Eurasia. In Europe, it has been detected in Portugal and Spain and is primarily associated with Pinus pinaster, an important Mediterranean tree species.Aims
We have investigated the differences in susceptibility among several P. pinaster provenances in the Iberian Peninsula and France, as well as their relationship to certain growth traits and physiological parameters.Methods
Three independent inoculation tests were performed on 3 to 4-year-old trees, followed by assessment of growth traits and physiological variables, along with time course destructive sampling for nematode quantification.Results
The results showed significant differences among provenances for almost all growth traits, wilting, and mortality, though a significant provenance × environment interaction was also detected. Two Atlantic provenances, Noroeste-Litoral and Leiria, displayed the largest susceptibility to pinewood nematode. Changes in susceptibility to B. xylophilus between experiments were influenced by temperature and seasonality. Autumn precipitation and mean maximum temperature during summer at the original provenance sites could be related to provenance susceptibility.Conclusion
Noroeste-Litoral and Leiria were the most disease-affected provenances. This study emphasizes the need for further research on how tree growth stage influences susceptibility and on the possibility of cross-breeding among provenances.9.
Gerónimo Quiñonez-Barraza Dehai Zhao Héctor M. De Los Santos Posadas José J. Corral-Rivas 《Annals of Forest Science》2018,75(3):78
Key message
More accurate diameter at breast height (dbh)-growth models are needed for developing management tools for mixed-species forests in Mexico. Individual distance-dependent dbh growth models that quantify local neighborhood effects have been developed for four species groups in such forests. The performance of the models is improved by distinguishing between inter- and intraspecific group competitions.Context
The management of mixed-species forests in the northwest of Durango, Mexico, is mainly based on the selection method. Understanding the interspecific and intraspecific competition is critical to developing management tools for such mixed-species forests.Aims
An individual-based distance-dependent modeling approach was used to model the growth of dbh and to evaluate neighborhood effects for four species groups in Mexican mixed-species stands.Methods
Twenty-two species were classified into four groups: Pinus (seven species), other conifers (three species), other broadleaves (four species), and Quercus (eight species). Four methods were used to select neighboring trees and 12 competition indices (CIs) were calculated. Comparisons of the neighboring trees selection methods and CIs and tests of assumptions about neighborhood effects were conducted.Results
Intra-species-group competition significantly reduced diameter growth for all species groups, except for the Quercus group. The Pinus, other conifers, and Quercus groups had significant and negative neighborhood effects on the other broadleaves species group, and not vice versa. The Quercus group also had negative neighborhood effect on the Pinus and other conifers species groups, and not vice versa. The Pinus and other conifers species groups had negative neighborhood effects on each other. All fitted age-independent dbh growth models showed a good of fit to the data (adjusted coefficient of determination larger than 0.977).Conclusion
The growth models can be used to predict dbh growth for species groups and competition in mixed-species stand from Durango, Mexico.10.
Key message
Seedling ontogeny exerted a greater influence on physiological activity of Quercus rubra seedlings than genetics; thus, it may be more important to use an appropriate growth index to account for seedling ontogeny in experiments than to control for genetic variation.Context
Members of the genus Quercus exhibit semi-determinate growth, resulting in complex and developmentally variable endogenous physiological patterns. The Quercus morphological index (QMI; Hanson et al. Tree Physiol. 2:273-281, 1986) was developed as a tool to relate physiological patterns to morphologically identifiable ontological stages, thereby allowing for treatment or measurement of seedlings at uniform ontological stages rather than strictly by chronology.Aims
Although clear physiological patterns relative to seedling ontogeny have been observed using the QMI in pre-transplant half-sibling seedlings, we sought to determine whether physiological patterns remain consistent across genotypes within a species.Methods
We examined net photosynthesis, transpiration, leaf chlorophyll concentrations, and chlorophyll fluorescence (F v /F m ) throughout the first flush after transplant for northern red oak (Quercus rubra L.) seedlings from three half-sibling families.Results
Neither net photosynthesis nor transpiration rates varied by family, whereas leaf chlorophyll concentrations and F v /F m differed significantly. Despite family differences for magnitudes of some parameters, no interactions between QMI growth stage and family were observed, and patterns of all parameters relative to growth stage were consistent across families. Net photosynthetic rates, transpiration rates, and F v /F m increased during the flush, while leaf chlorophyll concentration decreased, suggesting that chlorophyll synthesis is not a limiting factor during leaf maturation in this species.Conclusion
Findings indicate that QMI-based physiological patterns may be at least regionally applicable within a given Quercus species.11.
Huawei Ji Jiahao Wen Baoming Du Ningxiao Sun Björn Berg Chunjiang Liu 《Annals of Forest Science》2018,75(2):59
Key message
Foliar phosphorus (P) resorption in Quercus variabilis Blume was significantly lower at a P-rich than at a P-deficient site. Moreover, P resorption strongly decreased, and nitrogen:phosphorus and carbon:phosphorus resorption ratios increased with soil P content. This demonstrates a strong link between foliar P resorption and P content in soils, and emphasizes the importance of P resorption in leaves of trees growing in soils with contrasted P content.Context
Subtropical ecosystems are generally characterized by P-deficient soils. However, P-rich soils develop in phosphate rock areas.Aims
We compared the patterns of nutrient resorption, in terms of ecological stoichiometry, for two sites naturally varying in soil P content.Methods
The resorption efficiency (percentage of a nutrient recovered from senescing leaves) and proficiency (level to which nutrient concentration is reduced in senesced leaves) of 12 elements were determined in two oak (Q. variabilis) populations growing at a P-rich or a P-deficient site in subtropical China.Results
P resorption efficiency dominated the intraspecific variation in nutrient resorption between the two sites. Q. variabilis exhibited a low P resorption at the P-rich site and a high P resorption at the P-deficient site. Both P resorption efficiency and proficiency strongly decreased with soil P content only and were positively related to the N:P and C:P ratios in green and senesced leaves. Moreover, resorption efficiency ratios of both N:P and C:P were positively associated with soil P.Conclusion
These results revealed a strong link between P resorption and P stoichiometry in response to a P deficiency in the soil, and a single- and limiting-element control pattern of P resorption. Hence, these results provide new insights into the role of P resorption in plant adaptations to geologic variations of P in the subtropics.12.
Pedro Sánchez-Gómez Juan F. Jiménez Jose Luis Cánovas Juan Bautista Vera Isabell Hensen Miloud Aouissat 《Annals of Forest Science》2018,75(3):75
Key message
The genetic structure of Juniperus phoenicea in the Mediterranean Basin is inferred using amplified fragment length polymorphism markers (AFLP) markers. As other Mediterranean conifers, J. phoenicea populations show moderate levels of genetic diversity and interpopulational differentiation. The pattern of distribution of genetic diversity seems highly influenced by the climatic fluctuations which occurred in the Pleistocene.Context
It has been stated that the genetic structure of Mediterranean conifers is mediated by the historical climatic changes and the geological rearrangements which occurred in the Mediterranean Basin. J. phoenicea provides an excellent example to test how its genetic structure is influenced by these events.Aims
In this work, we study the amount and distribution of genetic diversity of J. phoenicea complex, in order to evaluate its taxonomic status and to reveal underlying phylogeographic patterns.Methods
The molecular diversity was analyzed for 805 individuals from 46 populations throughout its distribution range using AFLP markers. Principal coordinate analysis, analysis of molecular variance (AMOVA), and Bayesian-based analysis were applied to examine the population structure.Results
AFLP markers revealed moderate levels of intrapopulation genetic diversity, pairwise genetic differentiation, and a clear pattern of isolation by distance. Bayesian analysis of population structure showed five clusters related to the taxonomic status of J. phoenicea and J. turbinata, and a geographic pattern of genetic structure in J. turbinata.Conclusion
All the analysis separate J. phoenicea from J. turbinata. For J. turbinata, up to four groups can be distinguished from a phylogeographic point of view. The genetic structure of J. turbinata seems highly influenced by climatic and geologic fluctuations occurring since the Oligocene.13.
Key message
Radial growth of silver and red maples was investigated across three forests in northwest Ohio following the outbreak of the invasive emerald ash borer. The growth response of maples was driven by an advancement in canopy class and disturbance severity.Context
Forest disturbances resulting in species-specific diffuse mortality cause shifts in aboveground and belowground competition. This competition may differentially affect non-impacted trees, depending on crown class, disturbance severity, and species-specific responses.Aims
The purpose of this study is to elucidate the primary drivers of silver and red maple (Acer saccharinum and A. rubrum) growth following emerald ash borer (EAB, Agrilus planipennis)-induced ash tree (Fraxinus spp.) mortality in riparian forests of northwest Ohio.Methods
Using dendroecological approaches, we analyzed the pattern of radial growth in red and silver maples in conjunction with the EAB outbreak.Results
This study revealed growth rates of maples increased 72% following EAB arrival and trees advancing in crown class grew 41% faster than those not advancing. The growth response varied by initial crown class, with trees in the intermediate class responding most dramatically. Furthermore, the positive correlation between relative basal area of ash and the radial growth response of maples indicates the important role of disturbance severity in post-disturbance dynamics.Conclusion
These findings suggest that, although advancement in crown class may allow predictions of “winners” in forest succession post-disturbance, even trees not changing crown class benefit from decreased competition. Results from this study provide a detailed account of radial growth responses in maples following EAB-induced ash mortality and lend insight into the future canopy composition of ash-dominated riparian forests.14.
Key message
Pronounced clonal variation and moderate to high broad-sense heritability estimates of susceptibility to Neonectria neomacrospora were found in Abies nordmanniana in three sites. Significant genotype by environment (G × E) interaction was detected across sites.Context
Nordmann fir, a widely used Christmas tree species in Europe, has, since 2011, been increasingly damaged by a canker disease caused by Neonectria neomacrospora.Aims
The objective was to study the genetic variation and genotype by environment interaction in the susceptibility of Nordmann fir to N. neomacrospora.Methods
Damage caused by N. neomacrospora was evaluated using a visual scale in three Nordmann fir clonal seed orchards in Denmark, partly containing the same clones.Results
Damage due to N. neomacrospora was substantial at all three sites, and no clone was completely resistant to N. neomacrospora, but a large genetic variation in the susceptibility was detected among clones. Estimates of single-site individual broad-sense heritability for susceptibility varied between 0.38 and 0.47. The average type-B genetic correlation for damage score across sites was 0.34.Conclusion
Genetic variation was very pronounced, and significant G × E interactions were detected for susceptibility. Further investigations of narrow-sense heritability, expression of the trait in younger material, and identification of the cause of G × E for N. neomacrospora susceptibility in Nordmann fir across different sites are recommended.15.
Pau Brunet-Navarro Frank J. Sterck Jordi Vayreda Jordi Martinez-Vilalta Godefridus M.J. Mohren 《Annals of Forest Science》2016,73(4):1025-1034
Key message
Self-thinning lines are species- and climate-specific, and they should be used when assessing the capacity of different forest stands to increase biomass/carbon storage.Context
The capacity of forests to store carbon can help to mitigate the effects of atmospheric CO2 rise and climate change. The self-thinning relationship (average size measure ～ stand density) has been used to identify the potential capacity of biomass storage at a given density and to evaluate the effect of stand management on stored carbon. Here, a study that shows how the self-thinning line varies with species and climate is presented.Aims
Our main objective is thus testing whether species identity and climate affect the self-thinning line and therefore the potential amount of carbon stored in living biomass.Methods
The Ecological and Forest Inventory of Catalonia was used to calculate the self-thinning lines of four common coniferous species in Catalonia, NE Iberian Peninsula (Pinus halepensis, Pinus nigra, Pinus sylvestris and Pinus uncinata). Quadratic mean diameter at breast height was chosen as the average size measure. The self-thinning lines were used to predict the potential diameter at a given density and study the effect of environmental variability.Results
Species-specific self-thinning lines were obtained. The self-thinning exponent was consistent with the predicted values of ?3/2 and ?4/3 for mass-based scaling for all species except P. sylvestris. Species identity and climatic variability within species affected self-thinning line parameters.Conclusion
Self-thinning lines are species-specific and are affected by climatic conditions. These relationships can be used to refine predictions of the capacity of different forest stands to increase biomass/carbon storage.16.
Fleur Longuetaud Frédéric Mothe Philippe Santenoise Ndiaye Diop Jana Dlouha Meriem Fournier Christine Deleuze 《Annals of Forest Science》2017,74(3):64
? Key message
Intensive measurements of basic specific gravity and relative water content of lumens show that within-stem variations strongly depend on species and cannot be summarised through the typical patterns reported in the literature; breast height measurements are not always representative of the whole stem.? Context
Knowledge of the distribution of wood properties within the tree is essential for understanding tree physiology as well as for biomass estimations and for assessing the quality of wood products.? Aims
The radial and vertical variations of basic specific gravity (BSG) and relative water content of lumens (RWC L ) were studied for five species: Quercus petraea/robur, Fagus sylvatica, Acer pseudoplatanus, Abies alba and Pseudotsuga menziesii. The observations were compared with typical patterns of variations reported in the literature.? Methods
Wood discs were sampled regularly along tree stems and X-rayed in their fresh and oven-dry states.? Results
At breast height, BSG was found to clearly increase radially (pith to bark) for two species and to decrease for one species. For F. sylvatica and A. alba, the radial variations of BSG were rather U-shaped, with in particular inner wood areas showing respectively lower and higher BSG than the corresponding mature wood. RWC L increased generally from inner to outer area but wet sapwood was clearly distinguishable only for the coniferous species. Vertical variations of BSG and RWC L were strongly dependant on the species with usually non-linear patterns.? Conclusion
The observed variations of BSG were only partially in agreement with the reported typical radial patterns. Despite the vertical variations, the mean BSG of a cross-section at breast height appeared to be a good estimator of the mean BSG of the whole stem (although the difference was statistically significant for coniferous species), whereas breast height measurement of RWC L was not representative of the whole stem.17.
Shan Li Xiaohong Gan Hongyan Han Xuemei Zhang Zhongqiong Tian 《Annals of Forest Science》2018,75(3):74
Key message
Tetracentron sinense Oliver, an endangered species from China, displays a low within-population genetic diversity and high genetic differentiation among populations, and the existing populations could be divided into three conservation and management units.Context
The endangered tree Tetracentron sinense Oliver has great value; however, little is known regarding the within-population genetic diversity and differentiation among T. sinense populations.Aims
We examined the genetic diversity and differentiation of T. sinense wild populations, and we tested the effect of small-size population on the level of genetic diversity within these populations.Methods
Using inter-simple sequence repeat (ISSR), we assessed the genetic variation and structure among 174 individuals from 26 natural populations of T. sinense sampled across its distribution range in China.Results
The ISSR primers yielded 180 amplified loci (123 were polymorphic). At the species level, the percentage of polymorphic loci (PPL), Nei’s gene diversity (H), and Shannon’s information index (I) were 68.3%, 0.196 and 0.300, respectively. The average population level PPL was 20.0%, and the Na, Ne, H, and I were 1.20, 1.13, 0.076, and 0.112, respectively. AMOVA revealed high genetic differentiation among populations (52.0% of total variance, P?=?0.001), consistent with the gene differentiation coefficient (Gst?=?0.607) and gene flow (Nm?=?0.326). The 174 individuals of the 26 T. sinense populations clustered into three groups, and T. sinense geographic and genetic distance were significantly correlated.Conclusions
T. sinense exhibited intermediate within-species genetic diversity, indicating preserved evolutionary potential. The low within-population genetic diversity and high genetic differentiation among T. sinense populations may be one of important factors causing endangerment. Three conservation units were determined based on genetic difference and structure. Inter-population introduction of individuals within units via appropriate propagation and seedling management might be an effective strategy for increasing T. sinense within-population genetic diversity and population size.18.
Ching-Chu Tsai Li-Fen Hung Jeng-Der Chung Shiang-Jiuun Chen Ching-Te Chien Wen-Yuan Kao Ling-Long Kuo-Huang 《Annals of Forest Science》2018,75(2):52
Key message
The radial wood growth curves of Cinnamomum kanehirae Hayata (an endangered species of subtropical Taiwan) exhibit an S shape. The dominant trees displayed a larger radial growth than the codominant trees, and their growth was more sensitive to air temperature.Context
Knowledge of wood radial growth is important for evaluating the factors that limit tree growth performance. The relevant experiments have mostly been conducted in cold and temperate ecosystems, but rarely in subtropical ecosystems.Aims
In this study, we aimed to construct a unified radial growth model for Cinnamomum kanehirae Hayata and to identify its sensitivity to temperature.Methods
The wood radial increments were quantified for 3 years by either pinning or microcoring. The radial wood growth curves were modelled integratively by semiparametric regression and individually by curve fitting. The effects of tree social class, interannual and environmental factors on radial growth were analysed quantitatively.Results
A unified S-shaped growth model for C. kanehirae was successfully constructed. By including the social class effect, the model was significantly improved. The maximum radial increment (A) was significantly correlated with the maximum growth rate (μ); both A and μ were significantly higher in dominant than in codominant trees. The time-varying radial growth rate was more sensitive to air temperature in dominant than in codominant trees.Conclusion
Semiparametric models revealed an S-shaped growth curve of C. kanehirae and confirmed the higher temperature sensitivity of dominant trees compared to codominant trees in humid subtropical areas.19.
Barbara Moser Christoph Bachofen Jonathan D. Müller Marek Metslaid Thomas Wohlgemuth 《Annals of Forest Science》2016,73(4):959-970
Key message
Pinus sylvestris seedlings quickly expand their roots to deeper soil layers while Pseudotsuga menziesii concentrates its root system in the topsoil, thereby running the risk of desiccation during long dry spells, as indicated by lower survival after simulated summer drought.Context
Pseudotsuga menziesii (Douglas-fir) is regarded as a promising species to maintain the productivity of Central European lowland forests given the projected increase of long dry spells.Aims
Will the species be able to regenerate from seed and spread outside plantations in a drier temperate Europe?Methods
We measured the relative growth rate, biomass allocation, root architecture, and phenotypic plasticity of Pseudotsuga menziesii seedlings sown in a common garden and grown under current precipitation and prolonged drought, respectively. The species’ competitive ability with respect to Pinus sylvestris L., the most drought-tolerant native conifer in Central Europe, was assessed during three growing seasons.Results
Pinus sylvestris seedlings had higher relative growth rates than did Pseudotsuga menziesii seedlings, first in terms of aboveground biomass and later in terms of shoot height. This resulted in heavier and taller seedlings after three growing seasons under both moist and dry conditions. Shorter vertical roots corresponded with lower survival of Pseudotsuga menziesii seedlings under dry conditions.Conclusion
Fast root proliferation allows Pinus sylvestris seedlings to reach deeper water pools that are less rapidly depleted during transient drought. By contrast, the shallow root system might put Pseudotsuga menziesii seedlings at the risk of desiccation during prolonged dry spells.20.