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Billard Antoine Bauer Rodolphe Mothe Frédéric Colin Francis Christine Deleuze Longuetaud Fleur 《European Journal of Forest Research》2021,140(6):1401-1416
European Journal of Forest Research - Studies on wood basic density (BD) vertical variations become essential to predict more accurately the within-stem distributions of biomass and wood quality in... 相似文献
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Fleur Longuetaud Alexandre Piboule Holger Wernsdörfer Catherine Collet 《European Journal of Forest Research》2013,132(4):621-634
The objective of the study was to analyse to which extent horizontal crown plasticity reduces inter-tree competition at stand scale, and how it relates to species growth strategy. Two components of crown plasticity defined at the individual tree level (crown shape distortion, CSD and crown displacement relative to stem, CRD) were analysed and their relative importance in the reduction of competition was quantified. Inter-tree competition at stand scale was estimated using spatial pattern analysis and crown overlap estimation. Measurements were performed in a mixed broadleaved stand of Western Europe. Crown plasticity was shown to regularise the spatial distribution of crowns in comparison with the corresponding stems and to reduce inter-tree competition by optimising space occupation. A significant reduction in crown overlap was observed, mainly due to CRD and secondarily to CSD. At the species level, CSD and CRD were positively correlated. In addition, both were negatively correlated with species shade-tolerance scores. In particular, three European temperate tree species showed contrasting responses, which were related to their known specific ecological strategies. Fagus sylvatica, known to be a highly shade-tolerant species, showed large crowns, low CSD and CRD, indicating a low plasticity and suggesting a strong competitive ability. At the opposite, Quercus sp., known to be clearly less shade-tolerant, exhibited a reduced growth, associated with high CSD and CRD, indicating high crown plasticity and probably a lower competitive ability. For this species, plasticity could be described as passive. Last, Carpinus betulus, known to have a relatively good shade-tolerance, showed a contrasting behaviour with high CSD and CRD and a strong presence in the stand, suggesting high crown plasticity and a good competitive ability. In that case, plasticity was described as rather adaptive. 相似文献
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Measuring wood density by means of X-ray computer tomography 总被引:1,自引:0,他引:1
Charline Freyburger Fleur Longuetaud Frédéric Mothe Thiéry Constant Jean-Michel Leban 《Annals of Forest Science》2009,66(8):804-804
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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.
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