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Guillermo Riesco Muñoz Andrés Remacha Gete Manuel Gasalla Regueiro 《Annals of Forest Science》2013,70(7):695-706
Context
The commercial feasibility of sawmilling depends on the expected volume and value of sawn planks. Models that predict the volume of sawn timber of a particular quality and produced from logs of known characteristics are therefore very useful.Aims
The objectives were to study variation in sawing yield and to obtain models that predict lumber volume and grade recovery on the basis of easy-to-measure predictor variables of saw logs.Methods
Forty-six oak trees growing in Galicia (NW Spain) were felled and cut into logs. The logs were visually graded and sawn mainly into quartersawn planks, which were dried, planed and visually graded for structural purposes.Results
The total volumetric sawing yield was 47.6 %. The sawing yield for planks of structural dimensions (cross-section, 70?×?120 or 70?×?170 mm) was 43.4 %, but decreased to 8.4 % for structural sized and quality grade beams because of wane and biotic damage in many pieces. Log grade did not significantly affect sawing yield in the sample analysed, despite the wide range of diameter over bark at the smallest end in the sampled logs (22–77 cm). The sawing pattern affected total sawing yield (F?=?4.913; p value?=?0.001) and the sawing yield for structural planks (F?=?6.142; p value?=?0.0002); radial sawing with one cut and live sawing of half logs provided the highest yields. Three models were proposed for estimating sawn volume in timber products, with the small-end log diameter over bark as the predictor variable and R adj 2 between 0.31 and 0.78 (p value?<?0.01).Conclusion
For the purpose of producing oak timber destined for structural use, the presence of bark and sapwood in planks must be reduced in the sawing process; this would decrease the total lumber recovery but increase the timber value yield. Air drying must be accelerated to reduce biotic damage in sawn planks. Geometric mean diameter over bark at the smallest end (d) outperforms other measures as a predictor variable for total or structural sawn timber volume. 相似文献4.
Giulia Attocchi 《Annals of Forest Science》2013,70(7):663-673
Context
Avoidance or control of epicormic shoots is among the major silvicultural challenges for the production of high-quality oak timber. In northern Europe, contemporary oak silviculture aims to produce valuable timber on a relatively short rotation, applying early, heavy thinning combined with artificial pruning.Aims
The aim of this study was to analyse the effects of pruning and stand density on the production of new epicormic shoots on young trees of pedunculate oak (Quercus robur L.).Methods
The study was based on two field experiments in even-aged stands of pedunculate oak subjected to different thinning practices and early selection of potential future crop trees. From ages 13 to 15 years, stem density was reduced to 300 trees ha?1, 1,000 ha?1 or stands remained unthinned. Pruning was conducted on selected trees at ages 22–24 years. At that age, the stem density in unthinned control plots ranged from 2,500 to 3,100 ha?1. All treatments were replicated twice within each experiment.Results
Pruning led to an overall increase in the total production of new epicormic shoots. More epicormic shoots were produced in the lower part of the stem (0–3 m in height) than in the upper part (3–6 m). The number of new epicormic shoots increased with increasing stand density.Conclusion
Early, heavy thinning combined with high pruning at regular intervals may help shorten the rotation length for pedunculate oak without further reduction in wood quality than that which is caused by wider annual growth rings. 相似文献5.
Xingchang Wang Chuankuan Wang Quanzhi Zhang Xiankuai Quan 《Annals of Forest Science》2010,67(4):410-410
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Improving models of forest nutrient export with equations that predict the nutrient concentration of tree compartments 总被引：1，自引：0，他引：1
Laurent Augusto Céline Meredieu Didier Bert Pierre Trichet Annabel Porté Alexandre Bosc Frédéric Lagane Denis Loustau Sylvain Pellerin Frédéric Danjon Jacques Ranger Jacques Gelpe 《Annals of Forest Science》2008,65(8):808-808
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Context
Cluster planting has become a conventional establishment method for oaks in Central Europe, where the spacing of seedlings within clusters varies between ‘nests’ (0.2?×?0.2 m) and ‘groups’ (1?×?1 m). Although the space between clusters is expected to fill with voluntary regeneration, its competitive effect on oak growth and quality had not been studied yet.Aims
The aim of the study was to analyse the effects of inter- and intraspecific interactions on growth and quality of oaks grown in cluster plantings by quantifying the influence of neighbouring trees. In addition, we analysed whether the spatial position of oaks within groups (inner section or periphery) influenced their quality development.Methods
Using Hegyi’s competition index, the influence of competition from intra- and interspecific trees from early, mid- and late-successional species, on diameter, height, slenderness and quality (length of branch-free bole) of 10- to 26-year-old oaks grown in cluster planting stands was quantified at seven sites in Baden-Württemberg and Hessen, Germany.Results
In general, mid- and late-successional trees exerted a stronger competitive influence on growth of target oaks in clusters than the conspecific oaks and pioneer tree species. Oak quality development benefited from intraspecific competition, but self-pruning was not further promoted through additional interspecific competition. Within groups, inner oaks had a higher probability of developing into potential future crop trees than outer oaks.Conclusion
Our study showed that intra- and interspecific competition had different effects on target oak trees and that these effect differed between nest and group plantings. The development of naturally regenerated and planted trainer trees in group plantings should be monitored carefully and if necessary be controlled through thinning or pollarding. 相似文献9.
There has been a mass mortality of oak trees in the area along the coast of the Japan Sea. This phenomenon is caused by the ambrosia beetle Platypus quercivorus, which carries the ambrosia fungus Raffaelea quercivora. Extractives of a necrotic brownish coloration formed in the infected sapwood of Quercus crispula were investigated. The methanol extract of the damaged sapwood of Q. crispula was concentrated in vacuo and centrifuged to yield precipitates and the supernatant. The precipitates were subjected to Sephadex LH-20 column chromatography and preparative HPLC to describe a novel ellagic acid derivative (1). The 10 % methanol water-soluble part of the supernatant was subjected to medium-pressure ODS column chromatography and preparative HPLC, respectively, to analyze a known lignan (2). Sulfuric acid hydrolysis of (1) yielded an ellagic acid and a gallic acid. NMR and LC-TOF/MS indicated that an ellagic acid and a gallic acid bonded to a xylose with glycosidic and ester bonds, respectively. Compound (1) was identified as 4,5-dihydroxy-6-(3,7,8–trihydroxy-5,10-dihydro–chromeno[5,4,3-cde]chromen-2-yloxy)-tetrahydro-pyran-3-yl ester, and compound (2) was identified as (–)-lyoniresinol. The presence of (–)-lyoniresinol from damaged sapwood indicated that infection of R. quercivora may cause the formation of a pseudo-heartwood in the sapwood of Q. crispula. 相似文献
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Samah Mhamdi Oliver Brendel Pierre Montpied Hanah Ghouil-Amimi Ibrahim Hasnaoui Erwin Dreyer 《Annals of Forest Science》2013,70(7):675-684
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Oak species display a large within-species diversity combined with significant gene flow between species. Quercus afares Pomel is an endemic species that grows as a small relict population in Northern Tunisia, together with Quercus suber L. and Quercus canariensis Willd. It is considered to be a fixed hybrid between the two latter.?Aims
We tested (1) whether this population of Q. afares is declining with respect to the neighbouring populations of the two other species and (2) whether the spatial distribution of leaf morphology is random among individuals within this small population of Q. afares or influenced by the neighbouring species.?Methods
Spatial distribution and diameter at breast height were recorded in the population of Q. afares. We identified two perpendicular transects across the population reaching from areas dominated by Q. canariensis to areas dominated by Q. suber and defined 20 plots along each. Eleven traits were assessed on 10 leaves collected from the upper crown of trees from the three species. A multiple correspondence analysis and an ANOVA were used to test for within and between-species diversity in leaf morphology.?Results
Q. afares individuals occurred at a low frequency among the two other species. Nevertheless, Q. afares showed no particular evidence of decline with respect to the two other species. Leaf traits displayed a large inter-specific variability with very little overlap between Q. afares and Q. suber and some between Q. afares and Q. canariensis. A high level of diversity was detected for these traits within Q. afares, but we were unable to unravel any spatial organisation of this diversity; in Q. afares, leaf traits varied independently of the presence of neighbouring Q. suber or Q. canariensis.?Conclusion
Q. afares seems to be a fixed species with specific leaf traits that are independent of that of the species of the neighbouring trees. This population is not suffering a detectable trend towards decline except for the lack of any visible regeneration below any of the three species. 相似文献11.
Pressler cores of young clones of Quercus petraea and Q. roburwere analysed from two sites in Germany. Variation of wood colour(defined by the CIELAB system), density and heartwood ellagitanninswas examined between clones, species and sites. Similar studieswere made of cores from another trial of 20 half-sib familiesof parent trees deriving from five German forests. The resultsfrom both the clonal and progeny trials indicate that heartwoodellagitannin content and wood density are under strong geneticcontrol, while sapwood and heartwood colour are less so. A largeproportion of between-clone variation in wood density and ellagitanninlevels occurred between the two species, while these propertiesvaried little among ramets of the same clone grown on two contrastingsites, despite a difference in growth rates. A large proportionof the total variation among progeny was attributed to forestorigins and could not be attributed clearly to either geneticor environmental causes because of limitations of the samplingdesign 相似文献
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João Carvalho Óscar Cardoso Mário Costa Abel Rodrigues 《European Journal of Forest Research》2017,136(1):185-192
This work presents the results of a study on the variation of the chemical composition of Pyrenean oak (Quercus pyrenaica Willd.) heartwood among different sites and its relationship with the soil chemical characteristics. The chemical characteristics of the heartwood are quantified in terms of proximate and ultimate analysis, calorific value and ash composition. Subsequently, the relationship between the wood chemical characteristics and the soil characteristics was also examined. The results showed no significant differences between the wood chemical characteristics from different sites. There are, however, significant differences between trees from the same site regarding the wood ash content, the calorific value and the contents of nitrogen and hydrogen. Strong correlations were observed between the heartwood ash contents of BaO, MnO, CuO and TiO2 and the soil nitrogen, phosphorous and potassium and the soil exchangeable base contents. 相似文献
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Pressler cores were taken of Quercus petraea and Q. robur treesfrom young German provenance stands and mature mixed plantationsin England. The concentration of total phenolics extracted fromthe outer heartwood was measured and significant differencesfound between the two species. Concentrations of oak lactones,measured from provenance samples, also varied significantlybetween the species. However, the difference in total phenolicsbetween species was much lower among the trees from the mixedplantations than from the provenance trials. Q. petraea wascharacterized by lower levels of total phenolics but greaterconcentrations of oak lactones than Q. robur. A comparison betweenlate and early flushing Q. petraea trees found no significantdifference in total phenolics between these phenological types. 相似文献
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Fernando Silla Ana González-Gil Ma Esther González-Molina Sonia Mediavilla Alfonso Escudero 《Annals of Forest Science》2010,67(1):108-108
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J. Rodríguez-Calcerrada F. J. Cano M. Valbuena-Carabaña L. Gil I. Aranda 《New Forests》2010,39(2):245-259
The extent to which seedling recruitment is limited by summer drought in Mediterranean-type ecosystems depends on the light
microsite, yet the relationship between light availability and water status, functional performance, and survival of seedlings
in these systems is still unclear. Over a 3-year period, we studied the pattern of survival and functional performance of
seedlings of Quercus petraea (Matt.) Liebl. and Quercus pyrenaica Willd. in a montane forest in central Spain, which is the southern edge of the natural range of Q. petraea. After a mast year of the two species, 72 plots were established in six microhabitats spanning a range of overstorey canopy
closure: closed, partial and open canopies dominated by either Q. petraea or Q. pyrenaica adult trees. Seedlings of each species naturally emerged beneath the conspecific-dominated canopies. The second and third
years of study were extremely dry. Three years after emergence, the greatest seedling survival occurred beneath the partial
canopy of Q. pyrenaica trees (8%) and the lowest (0%) beneath the closed canopies of Q. pyrenaica and Q. petraea. Survival for Q. pyrenaica increased linearly with understorey light across the range of 10–35% Global Site Factor. Plant water deficit (estimated by
leaf water potential) was high across microhabitats, and increased with light availability for Q. pyrenaica. Potential for photosynthesis (estimated by the electron transport rate of photosystem II) decreased with canopy closure;
and potential for light harvesting (e.g. specific leaf area (SLA) and chlorophyll concentration) increased with closure. Extreme
water deficit could be the main contributor to seedling death in the more open microhabitats, whereas light level was insufficient
to maintain carbon balance under the water-stressful conditions existing beneath the closed tree canopies. Seedling establishment
appears to be a limiting factor for the recruitment of both oaks within this forest in a wide range of microhabitats, especially
for the more drought-sensitive Q. petraea. Moderate reductions of tree canopy cover can improve seedling establishment, but extreme summer droughts can prevent the
success of any silvicultural practice made. 相似文献
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Hans Pretzsch Kamil Bielak Joachim Block Arkadiusz Bruchwald Jochen Dieler Hans-Peter Ehrhart Ulrich Kohnle Jürgen Nagel Hermann Spellmann Michał Zasada Andreas Zingg 《European Journal of Forest Research》2013,132(2):263-280
The mixture of beech (Fagus sylvatica L.) and oak (sessile oak, Quercus petraea (Matt.) Liebl., and pedunculate oak, Q. robur L.) is of considerable importance in Europe and will probably become even more important under climate change. Therefore, the performance of oak and beech in mixture was compared with the species’ growth in pure stands. Data from 37 long-term mixing experiments in Poland, Germany and Switzerland were pooled for analysis of mixing effects on stand productivity and possible interrelationships with mixing portions or site conditions. We found that on average, mixed stands of oak and beech exceeded biomass productivity in pure stands by 30 % or 1.7 t ha?1 year?1, as the growth of both species was benefitted by the mixture. However, that the interaction actually ranged from facilitation and overyielding on poor sites to underyielding on fertile sites triggered by competition. An empirically derived interaction model showed volume and dry mass growth changing in mixed stands from gains of 50 % to losses of 10 % depending on site conditions. It is concluded that the analysed mixture grows in accordance with the stress-gradient hypothesis and that our results suggest a site-specific relationship between species mixture and biomass productivity. As a consequence, an adequate species mix should result in increased productivity under steady state as well as climate change. 相似文献
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Context
Genetic diversity of sessile oak (Quercus petraea) populations in Hungary was assessed close to the retracting, low-elevation, low-latitude (xeric) distribution limits.Objective
We aimed at tracing an assumed effect of climatic factors on genetic diversity, particularly at the southern, low elevation limits of distribution.Methods
Genetic diversity at isozyme-coding loci was analysed in populations, and related to the climate of the sites where the populations grow. A locus-wise analysis proved to be essential to follow responses.Results
A climate-related cline was found at seven isoenzyme-coding gene loci. Declining allelic numbers and heterozygosity indicated lower diversity at warmer and drier sites. The majority of loci were responsive to precipitation factors, others to temperature. Genetic clustering was neither related to geographic distance nor to random or historic effects.Conclusions
The results suggest that climatic stress may elicit a genetic diversity loss in populations, which may reduce their plasticity and adaptive potential. The selective pressure may override historic effects and gene flow. With respect to expected climate change, the correlation of diversity with some climatic factors gains specific importance. If supported by further investigations, the results might be utilised for reconsidering conservation strategies and rules for use of forest reproductive material. 相似文献18.
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.19.
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