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Acacia catechu (Sha)-bearing forests are the primary sources of cutch, a tannin extract from the heartwood of Sha trees. Sha forests in Myanmar are managed for cutch production, and tree harvesting for cutch is regulated by an official diameter limit (ODL, 30 cm DBH [diameter at breast height]). We explored sustainable Sha forest management for cutch production through stand inventory surveys and informal interviews with locals and forest managers. We compared Sha forests with six different official harvest histories and assessed seedlings and saplings as well as the size and species of harvested stumps and remaining trees. We found that the forest understory was disturbed by surface fire, and all Sha seedlings and saplings < 1.7 m in height showed post-fire marks. We observed a regeneration gap between 1.7 m and 2.7 m, which might indicate the flame height of the surface fire. The “illegal” harvest exceeded the official harvest; only 5% of the harvested stumps were found to be larger than the ODL. Local harvesting of cutch appeared to be limited by the stem diameter required for heartwood formation (15 cm DBH). Stump data revealed that the forests were utilized not only for cutch but also for other purposes, including fuel and timber. Despite fire and local harvesting, local forest utilization patterns appear to be reasonable, although they are illegal. Implementing fire control and community management of forests along with clear definition of property rights could help in sustainably managing Sha forests for cutch production.# en

Taiwania (Taiwania cryptomerioides Hayata) has long been regarded as a living fossil from the Tertiary period of Mesozoic Era for its distinguished yellowish-red color with purplish-pink streaks presented in its heartwood. With this elegant appearance that matches the color “red” for good fortune in the Taiwanese culture, Taiwania is supposed to be a popular wood in Taiwan where it is a native species of. Extractives contribute to the properties of wood. It is a fascinating subject to investigate extractives biosynthesis in the process of heartwood formation. Up to date, there is no phytochemistry study of Taiwania sapwood. In this study, three new sesquiterpenoids, Taiwania A (1), Taiwania B (2), and Taiwania C (3), together with 75 known compounds in the Taiwania sapwood. The structures of extractives were determined by analysis of spectroscopic data and comparison with the literatures. This study supported secondary reaction lignans could be found in sapwood that confirmed our previous research on the Taiwania-type of heartwood formation.

Forensic methods to independently trace timber origin are essential to combat illegal timber trade. Tracing product origin by analysing their multi-element composition has been successfully applied in several commodities, but its potential for timber is not yet known. To evaluate this potential the drivers of wood multi-elemental composition need to be studied. Here we report on the first study relating wood multi-elemental composition of forest trees to soil chemical and physical properties. We studied the reactive soil element pools and the multi-elemental composition in sapwood and heartwood for 37 Azobé (Lophira alata) trees at two forest sites in Cameroon. A total of 46 elements were measured using ICP-MS. We also measured three potential drivers of soil and wood elemental composition: clay content, soil organic matter and pH. We tested associations between soil and wood using multiple regressions and multivariate analyses (Mantel test, db-RDA). Finally, we performed a Random Forest analysis of heartwood elemental composition to check site assignment accuracy. We found elemental compositions of soil, sapwood and heartwood to be significantly associated. Soil clay content and organic matter positively influenced individual element concentrations (for 13 and 9 elements out of 46 respectively) as well as the multi-elemental composition in wood. However, associations between wood and topsoil elemental concentrations were only significant for one element. We found close associations between element concentrations and composition in sapwood and heartwood. Lastly, the Random Forest assignment success was 97.3 %. Our findings indicate that wood elemental composition is associated with that in the topsoil and its variation is related to soil clay and organic matter content. These associations suggests that the multi-elemental composition of wood can yield chemical fingerprints obtained from sites that differ in soil properties. This finding in addition to the high assignment accuracy shows potential of multi-element analysis for tracing wood origin.

Molecular genetic markers of various PCD (programmed cell death) variants during xylo- and phloemogenesis have been identified for the first time in Scots pine under lingonberry pine forest conditions in Northwest Russia (middle taiga subzone). PCD is a genetically determined process. Gene profiles of serine and cysteine proteases (endopeptidases), endonucleases, and metacaspases families are often considered markers of the final xylogenesis stage. In the present study, we examined the gene expression profiles of the BFN (bifunctional endonuclease) family—BFN, BFN1, BFN2, BFN3, and peptidase (cysteine endopeptidase, CEP and metacaspase, MC5) in the radial row, in addition to the vascular phloem and cambium (F1), differentiating xylem (F2), sapwood (SW), and transition zone during the active cambial growth period of uneven-aged pine trees (25-, 63- and 164-cambial age (c.a.) years old). We have shown that the expression patterns of the PCD-related genes did not depend on the cambial age but were largely determined by plant tissue type. In the radial row F1-F2-SW, we studied the activities of enzymes, including sucrose in metabolism (sucrose synthase, three forms of invertase); antioxidant system (AOS) enzymes (superoxide dismutase, catalase); and peroxidase andpolyphenol oxidase, which belonged to AOS enzymes and were involved in the synthesis of phenolic components of cell walls. The activity of the enzymes indicated that the trunk tissues of pine trees had varying metabolic status. Molecular genetic PCD regulation mechanisms during xylem vascular and mechanical element formation and parenchyma cells’ PCD during the formation of Scots pine heartwood were discussed.

Five chemical elicitors––6-benzyladenine (BA), ethephon (ETH), methyl jasmonate (MeJA), hydrogen peroxide (H2O2) and calcium chloride (CaCl2)––were used to treat 1- and 5-year-old sandal trees (Santalum album L.) to assess their effects on growth, heartwood formation and concrete oil synthesis. The results showed that some newly formed branches in stems that were induced by BA and ETH displayed leaf senescence and developed new smaller and light-green leaves. The relative percentage of concrete oil from the heartwood of water-treated trees (0.65%) was significantly lower than that from trees treated with 4 mM H2O2 (2.85%) and 4 mM BA (2.75%) within one year. Four mM BA, H2O2 and CaCl2 induced a significantly higher level of sesquiterpenoids than heartwood treated with 2 mM of these elicitors. Four mM MeJA induced significantly less sesquiterpenoids than heartwood treated with 2 mM MeJA. Morphological, physiological, and chromatographic–spectrometric technologies were integrated to trace the potential function of these exogenously applied chemical elicitors. The results may have important applications and provide a better understanding of the molecular mechanism of heartwood formation and hardening in young sandalwood trees.

Five chemical elicitors––6-benzyladenine (BA), ethephon (ETH), methyl jasmonate (MeJA), hydrogen peroxide (H2O2) and calcium chloride (CaCl2)––were used to treat 1- and 5-year-old sandal trees (Santalum album L.) to assess their effects on growth, heartwood formation and concrete oil synthesis. The results showed that some newly formed branches in stems that were induced by BA and ETH displayed leaf senescence and developed new smaller and light-green leaves. The relative percentage of concrete oil from the heartwood of water-treated trees (0.65%) was significantly lower than that from trees treated with 4 mM H2O2 (2.85%) and 4 mM BA (2.75%) within one year. Four mM BA, H2O2 and CaCl2 induced a significantly higher level of sesquiterpenoids than heartwood treated with 2 mM of these elicitors. Four mM MeJA induced significantly less sesquiterpenoids than heartwood treated with 2 mM MeJA. Morphological, physiological, and chromatographic–spectrometric technologies were integrated to trace the potential function of these exogenously applied chemical elicitors. The results may have important applications and provide a better understanding of the molecular mechanism of heartwood formation and hardening in young sandalwood trees.

Taiwania (Taiwania cryptomerioides) is an important tree species in Taiwan because of the excellent properties of its wood and fascinating color qualities of its heartwood (HW), as well as the bioactive compounds therein. However, limited information is available as to the HW formation of this species. The objective of this research is to analyze the differentially expressed genes (DEGs) during the HW formation process from specific Taiwania xylem tissues, and to obtain genes that might be closely associated with this process. The results indicated that our analyses have captured DEGs representative to the HW formation process of Taiwania. DEGs related to the terpenoid biosynthesis pathway were all up-regulated in the transition zone (TZ) to support the biosynthesis and accumulation of terpenoids. Many DEGs related to lignin biosynthesis, and two DEGs related to pinoresinol reductase (PrR)/pinoresinol lariciresinol reductase (PLR), were up-regulated in TZ. These DEGs together are likely involved in providing the precursors for the subsequent lignan biosynthesis. Several transcription factor-, nuclease-, and protease-encoding DEGs were also highly expressed in TZ, and these DEGs might be involved in the regulation of secondary metabolite biosynthesis and the autolysis of the cellular components of ray parenchyma cells in TZ. These results provide further insights into the process of HW formation in Taiwania.

Formation of extractive-rich heartwood is a process in live trees that make them and the wood obtained from them more resistant to fungal degradation. Despite the importance of this natural mechanism, little is known about the deposition pathways and cellular level distribution of extractives. Here we follow heartwood formation in Larix gmelinii var. Japonica by use of synchrotron infrared images analyzed by the unmixing method Multivariate Curve Resolution – Alternating Least Squares (MCR-ALS). A subset of the specimens was also analyzed using atomic force microscopy infrared spectroscopy. The main spectral changes observed in the transition zone when going from sapwood to heartwood was a decrease in the intensity of a peak at approximately 1660 cm-1 and an increase in a peak at approximately 1640 cm-1. There are several possible interpretations of this observation. One possibility that is supported by the MCR-ALS unmixing is that heartwood formation in larch is a type II or Juglans-type of heartwood formation, where phenolic precursors to extractives accumulate in the sapwood rays. They are then oxidized and/or condensed in the transition zone and spread to the neighboring cells in the heartwood., Frontiers in Plant Science, 10, ISSN:1664-462X

This paper reviews the literature on heartwood and its formation process. The factors involved in the process of heartwood formation are described, with particular attention paid to molecular, intercellular, organismal and environmental ones. The spatial distribution of heartwood along longitudinal and radial axes of the stem as well as biochemical changes in the heartwood and durability of this zone are also presented. Based on the literature data, it turns out that the heartwood formation is neither clearly studied, nor fully understood. It seems that this part of wood can not only play a significant role from the point of view of tree biomechanics, but also is of great importance in their immune responses. In the era of observed dying processes of forest−forming trees, knowledge about the role of heartwood in these responses seems desirable., Sylwan 164 (6): 474-481

The objective of this work was to evaluate the influence of different useful areas provided by the planting spacings (3 × 1, 3 × 2, 3 × 3, 3 × 4 m) on the production and permeability of heartwood and sapwood of Eucalyptus grandis and Eucalyptus grandis × Eucalyptus urophylla clones at 4 years old. Regardless of the clone, there was no effect of planting spacing on the heartwood/sapwood relation and wood permeability. All clones showed a heartwood decrease with increased height, regardless of planting spacing, and E. grandis (B) was the only one that had its heartwood percentage positively and significantly correlated with the dendrometric variables (DBH and commercial height). The use of the dymethil yellow compound was indispensable in defining the heartwood and sapwood regions in the samples from 50% of the stem height. The heartwood permeability was low in all evaluated clones, suggesting vessel obstruction by tyloses or other deposits, while sapwood permeability reached 405.4 cm3/cm.atm.s. RESUMO O objetivo deste trabalho foi avaliar a influência de diferentes áreas úteis proporcionadas pelos espaçamentos de plantio (3 × 1, 3 × 2, 3 × 3, 3 × 4 m) na produção e na permeabilidade do cerne e do alburno da madeira de clones de Eucalyptus grandis e Eucalyptus grandis × Eucalyptus urophylla, aos 4 anos de idade. Independente do clone, não houve efeito do espaçamento de plantio na relação cerne/alburno e na permeabilidade da madeira. Todos os clones apresentaram um decréscimo na quantidade de cerne com o aumento da altura do fuste, independentemente do espaçamento de plantio, e o E. grandis (B) foi o único que a percentagem de cerne correlacionou-se positiva e significativamente com as variáveis dendrométricas (DAP e altura comercial). O uso do composto dymethil yellow foi indispensável na demarcação das regiões do cerne e do alburno nas amostras a partir de 50% da altura do fuste. A permeabilidade do cerne foi baixa em todos os clones avaliados, sugerindo obstrução dos vasos por tilas ou outras substâncias, enquanto a permeabilidade do alburno atingiu 405,4 cm3/cm.atm.s.

The transition from the living water-transporting sapwood to heartwood involves in many tree species impregnation with extractives. These differ in amount and composition, and enhance resistance against bacteria, insects or fungi. To understand the synthesis, transport and impregnation processes new insights into the biochemical processes are needed by in-situ methods. Here we show the extractive distribution in pine (Pinus sylvestris) microsections with a high lateral resolution sampled in a non-destructive manner using Confocal Raman Microscopy. Integrating marker bands of stilbenes and lipids enables to clearly track the rapid change from sapwood to heartwood within one tree ring. The higher impregnation of the cell corner, compound middle lamella, the S3 layer and pits reveals the optimization of decay resistance on the micron-level. Furthermore, deposits with changing chemical composition are elucidated in the rays and lumen of the tracheids. The spectral signature of these deposits shows the co-location of lipids and pinosylvins with changing ratios from the living to the dead tissue. The results demonstrate that the extractive impregnation on the micro- and nano-level is optimized by a symbiotic relationship of lipids and pinosylvins to enhance the tree’s resistance and lifetime.

International audience; Challenging evaluation of tropical forest biodiversity requires the reporting of taxonomic diversity but also the systematic characterization of wood properties in order to discover new promising species for timber industry. Among wood properties, the dimensional stability is regarded as a major technological characteristic to validate whether a wood species is adapted to commercial uses. Cell structure and organization are known to influence the drying shrinkage making wood density and microfibrils angle markers of choice to predict wood dimensional stability. On the contrary the role of wood extractive content remains unclear. This work focuses on the fast-growing tropical species Bagassa guianensis and we report herein a correlation between heartwood drying shrinkage and extractive content. Chemical extractions and shrinkage experiments were performed on separate wood twin samples to better evaluate correctly how secondary metabolites influence the wood shrinkage behaviour. Extractive content were qualitatively and quantitatively analysed using HPLC and NMR spectroscopy. We found that B guianensis heartwood has a homogeneous low shrinkage along its radius that could not be explained only by its basic density. In fact the low drying shrinkage is correlated to the high extractive content and a corrected model to improve the prediction of wood dimensional stability is presented. Additionally NMR experiments conducted on sapwood and heartwood extracts demonstrate that secondary metabolites biosynthesis occurs in sapwood thus revealing B. guianensis as a Juglans-Type heartwood formation. This work demonstrates that B. guianensis, a fast-growing species associated with high durability and high dimensional stability, is a good candidate for lumber production and commercial purposes.

National audience; Dans le cadre de recherches génériques sur les déterminants génétiques, moléculaires et biochimiques de la qualité du bois, il a été mis en évidence d’intéressantes propriétés biologiques et colorantes au niveau de deux types d’extraits de bois de robinier (Robinia pseudoacacia). Bien représentée en métropole et en région Centre, cette essence fixe naturellement l’azote atmosphérique, s’accommode de sols peu fertiles et est tolérante au stress hydrique. Elle représente de ce fait une espèce de choix pour la production de biomasse et la séquestration de carbone sur des friches non-agricoles qui ne peuvent être valorisées par d’autres espèces pérennes généralement plantées dans ces buts comme le peuplier ou le saule. Vu la proportion importante de bois de coeur présente chez le robinier, la mise en place, d’unités de production d’extraits ou de molécules de haute valeur ajoutée à partir de cette ressource locale semble judicieuse en complément des filières d’utilisation classiques de ce bois (bois-énergie, fabrication de piquets et de menuiseries extérieures). En relation avec des partenaires régionaux fortement impliqués dans les filières cosmétiques et phytosanitaires potentiellement utilisatrices de ces nouveaux produits issus du bois, le projet ValRob vise à confirmer la nature et l’activité des deux molécules en jeu, à estimer la variabilité génétique de leurs teneurs au sein des ressources génétiques françaises de robinier et finalement, à concrétiser leur production et leur valorisation au niveau industriel en tenant compte des données socio-économiques de la filière bois-forêt bien implantée au niveau régional.

Wood is a multifunctional tissue involved in sap conduction, storage of water and reserves as well as mechanical support. Tree during its development experiments various constraints due to its environment and its growing size. In response to these constraints, wood functional performances are adjusted by variations of property values, which are dependent on the xylogenesis product. However, wood properties may be modified by the deposition of chemical extractives during heartwood formation. Thus heartwood properties are the result of xylogenesis, heartwood formation and their interactions. This work gave rise to the term 'wood profile', designating all variations of wood properties at different scales and in an ontogenetic dimension, resulting from both processes described above. The diversity of shade tolerance (heliophilic to sciaphilic) strategies species suggests a diversity of wood profile expressions. The description of these different expressions could be a way to better understand plant strategies. Understanding and characterizing wood profile and variations in heartwood quantity in tree, is an economical issue since the Guyanese timber industry has been identified as a promising sector. The analysis of the diversity of wood profile—using a bottom-up approach, from the individual level to the interspecific level—proves to discriminate shade tolerance strategies efficiently. Wood specific gravity variation is especially relevant. However, its relevance is based on (1) combinations of both radial and vertical variations and (2) integration of heartwood that may impact range and direction of the gradient and shape of the profile as well. Effect of heartwood formation on wood specific gravity variations is suggestive of shade tolerance strategy as well as quality and/or quantity of chemical extractives. Relevant characterization of shade tolerance strategies by wood profile is the result of the integration of diverse processes and properties. To the view of growth allocation shift (from trunk to crown) observed in Dicorynia guianensis and of previous studies on tree growth, a potential link between wood profile diversity and growth allocation strategies may exist.; Le bois est un tissu plurifonctionnel permettant la conduction de la sève brute, le stockage de l’eau et des sucres ainsi que le soutien mécanique de la plante. L’arbre au cours de son développement expérimente différentes contraintes liées à son environnement et à sa taille croissante. En réponse à ces contraintes, les performances fonctionnelles du bois sont ajustées par des variations de valeurs de propriétés, elles-mêmes dépendantes du produit de la xylogénèse. Cependant les extrais chimiques déposés lors du processus de duraminisation, entraine la modification des propriétés du bois. Les propriétés du duramen sont le fruit de la xylognénése et de la duraminisation ainsi que de leurs interactions. Ce travail de thèse a donné naissance au terme ‘profil ligneux’, désignant l’ensemble des variations des propriétés du bois à différentes échelles et dans une dimension ontogénique résultant des deux processus cités précédemment. La diversité de tempéraments vis-à-vis de la lumière (héliophilie à sciaphilie) des essences tropicales suggère une diversité d’expressions du profil ligneux.La description de ces différentes expressions serait gage d’une meilleure compréhension du tempérament.Comprendre et caractériser le profil ligneux et la variation de la quantité de bois de coeur dans l’arbre, représentent également un enjeu économique puisque l’industrie du bois Guyanaise a été identifiée comme une filière d’avenir. L’analyse de la diversité du profil ligneux—par une approche ascendante, de l’échelle individuelle à l’échelle interspécifique—a prouvé son efficacité dans la discrimination du degré d’affinité à la lumière. La variation de densité est particuliérment pertinente. Néanmoins, sa pertinence réside dans (1) la combinaison du gradient radial et vertical et (2) la prise en compte du duramen qui modifie parfois, l’amplitude et la direction du gradient ainsi que la forme du profil. L’effet de la duraminisation sur la variation de densité devient alors évocateur du tempérament de l’espèce au même titre que la qualité et/ou la quantité d’extraits chimiques mis en jeu. La pertinence du profil ligneux dans la caractérisation du tempérament écologique est due à son aspect intégrateur de divers processus et propriétés. En regard du changement de l’allocation de croissance (i.e. du tronc vers la couronne) observé chez Dicorynia guianensis et de travaux précédents sur la croissance des arbres, un lien potentiel entre la diversité du profil ligneux et la stratégie d’allocation de la croissance pourrait exister.

International audience; Allometry of sapwood/heartwood is essential for understanding tree growth, water transport and carbon allocation, timber production and use, but such an allometry is lacking for Chinese temperate tree species.* We studied the allometry and development of heartwood and sapwood for seven Chinese temperate tree species: Korean pine (Pinus koraiensis Sieb. et Zucc), Dahurian larch (Larix gmelinii Rupr.), Japanese elm (Ulmus davidiana Planch var. japonica (Rehd.) Nakai), Manchurian ash (Fraxinus mandshurica Rupr.), Manchurian walnut (Juglans mandshurica Maxim.), Amur cork-tree (Phellodendron amurense Rupr.), and Mongolian oak (Quercus mongolica Fisch.). * All heartwood parameters investigated, including heartwood radius (HR), heartwood formation rate (HFR), heartwood ring number (HRN), heartwood initiation age (HIA), and heartwood volume ratio (HVR), were positively correlated with tree cambial age (CA). The HR, sapwood width (SW), sapwood area (SA), heartwood and sapwood volumes were significantly related to stem diameter at breast height (DBH) or xylem diameter. There was a polynomial relationship between the sapwood ring longevity (SRL) and sapwood ring number (SRN). However, most of the allometric relationships were species-dependent. The hardwood formation patterns were different between coniferous and broadleaved tree species. A power function was suitable to scale SA from DBH, but the exponent varied from 1.32 for the larch to 2.19 for the cork-tree.* Our allometry provided a practical means to assess wood development and related physiology for the temperate tree species.; L'allométrie de l'aubier/bois de cœur est essentielle pour comprendre la croissance de l'arbre, le transport de l'eau et l'allocation, la production et l'usage du bois, mais cette allométrie est manquante pour les espèces d'arbres chinoises de milieu tempéré.* Nous avons étudié l'allométrie et le développement du bois de coeur et de l'aubier pour sept espèces d'arbres tempérées chinoises : le pin de Corée (Pinus koraiensis Sieb. et Zucc), le mélèze de Dahurie (Larix gmelinii Rupr.), l'orme du Japon (Ulmus davidiana Planch var. japonica (Rehd.) Nakai), le frêne de Mandchourie (Fraxinus mandshurica Rupr.), le noyer de Mandchourie (Juglans mandshurica Maxim.), le phellodendron de l'Amur (Phellodendron amurense Rupr.), et le chêne de Mongolie (Quercus mongolica Fisch.).* Les paramètres du bois de coeur étudiés sont le rayon (HR), le taux de formation (HFR), l'âge d'initiation (HIA) et le ratio du volume (HVR) : ils sont corrélés positivement à l'âge cambial (CA). Le rayon du bois de cœur (HR), la largeur d'aubier (SW), la surface d'aubier (SA), les volumes de bois de cœur et d'aubier sont significativement liés au diamètre à hauteur de poitrine (DBH). Il y a une relation polynomiale entre la durée de vie des cernes d'aubier (SRL) et le nombre de cernes (SRN). Cependant la plus part des relations allométriques dépendent des espèces. Le patron de formation du bois de cœur diffère entre résineux et feuillus. Une fonction puissance est adaptée pour calibrer les variations de SA à partir de DBH mais l'exposant varie de 1,32 pour le mélèze à 2,19 pour le phellodendron de l'Amur.* Pour les essences d'arbres tempérées, notre allométrie fournit un moyen pratique pour estimer le développement du bois en tenant compte de la physiologie qui y est associée.

International audience; Allometry of sapwood/heartwood is essential for understanding tree growth, water transport and carbon allocation, timber production and use, but such an allometry is lacking for Chinese temperate tree species.* We studied the allometry and development of heartwood and sapwood for seven Chinese temperate tree species: Korean pine (Pinus koraiensis Sieb. et Zucc), Dahurian larch (Larix gmelinii Rupr.), Japanese elm (Ulmus davidiana Planch var. japonica (Rehd.) Nakai), Manchurian ash (Fraxinus mandshurica Rupr.), Manchurian walnut (Juglans mandshurica Maxim.), Amur cork-tree (Phellodendron amurense Rupr.), and Mongolian oak (Quercus mongolica Fisch.). * All heartwood parameters investigated, including heartwood radius (HR), heartwood formation rate (HFR), heartwood ring number (HRN), heartwood initiation age (HIA), and heartwood volume ratio (HVR), were positively correlated with tree cambial age (CA). The HR, sapwood width (SW), sapwood area (SA), heartwood and sapwood volumes were significantly related to stem diameter at breast height (DBH) or xylem diameter. There was a polynomial relationship between the sapwood ring longevity (SRL) and sapwood ring number (SRN). However, most of the allometric relationships were species-dependent. The hardwood formation patterns were different between coniferous and broadleaved tree species. A power function was suitable to scale SA from DBH, but the exponent varied from 1.32 for the larch to 2.19 for the cork-tree.* Our allometry provided a practical means to assess wood development and related physiology for the temperate tree species.; L'allométrie de l'aubier/bois de cœur est essentielle pour comprendre la croissance de l'arbre, le transport de l'eau et l'allocation, la production et l'usage du bois, mais cette allométrie est manquante pour les espèces d'arbres chinoises de milieu tempéré.* Nous avons étudié l'allométrie et le développement du bois de coeur et de l'aubier pour sept espèces d'arbres tempérées chinoises : le pin de Corée (Pinus koraiensis Sieb. et Zucc), le mélèze de Dahurie (Larix gmelinii Rupr.), l'orme du Japon (Ulmus davidiana Planch var. japonica (Rehd.) Nakai), le frêne de Mandchourie (Fraxinus mandshurica Rupr.), le noyer de Mandchourie (Juglans mandshurica Maxim.), le phellodendron de l'Amur (Phellodendron amurense Rupr.), et le chêne de Mongolie (Quercus mongolica Fisch.).* Les paramètres du bois de coeur étudiés sont le rayon (HR), le taux de formation (HFR), l'âge d'initiation (HIA) et le ratio du volume (HVR) : ils sont corrélés positivement à l'âge cambial (CA). Le rayon du bois de cœur (HR), la largeur d'aubier (SW), la surface d'aubier (SA), les volumes de bois de cœur et d'aubier sont significativement liés au diamètre à hauteur de poitrine (DBH). Il y a une relation polynomiale entre la durée de vie des cernes d'aubier (SRL) et le nombre de cernes (SRN). Cependant la plus part des relations allométriques dépendent des espèces. Le patron de formation du bois de cœur diffère entre résineux et feuillus. Une fonction puissance est adaptée pour calibrer les variations de SA à partir de DBH mais l'exposant varie de 1,32 pour le mélèze à 2,19 pour le phellodendron de l'Amur.* Pour les essences d'arbres tempérées, notre allométrie fournit un moyen pratique pour estimer le développement du bois en tenant compte de la physiologie qui y est associée.