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Communication Dans Un Congrès Année : 2007

Is porous wood structure exclusive of deciduous trees ?

Anais A Boura
Dario De Franceschi

Résumé

According to the IAWA committee (1989) the ring porous wood is defined a “wood in which the vessels in the earlywood are distinctly larger than those in the latewood of the previous and of the same growth ring“. An abrupt change of size and density of vessels between early and late wood allows distinguishing, in some extent, species with ring porous wood from species with semi-ring porous or diffuse porous wood. Nevertheless, some species show a continuum between the different states of porosity, depending upon the environmental conditions. In ring porous structure, the earlywood characteristics offer conductive efficiency. The embolism, result of drought stress, induces the inefficiency of the largest vessels of the previous year. The latewood including smallest vessels is of less efficiency, but offer a better conductive safety regarding the embolism phenomenon. The ring porous structure is thus considered as an adaptation of seasonal climates (Carlquist 2001). The young leaves are responsible to the increase of cambial activity, size and density of vessels through the production of auxin. Then, the earlywood formation is mainly induced by the leaf growth flushes. This should be particularly true on deciduous trees, which loose leaves and then produce new leaves simultaneously on the whole crown. Some authors have already mentioned this potential correlation between ring porous structure and the deciduousness of the trees (Gilbert 1940, Wheeler & Baas 1993, Poole & van Bergen 2006), but no precise inventory of species have been provided until now to verify this hypothesis. We compared, with the help of Insidewood (2004) and diverse floras, the wood porosity of 1503 species of temperate countries and 3419 of tropical countries and their foliage characteristics. Porous wood structure occurs in 16 % of the studied species under temperate climate and 2 % in tropical countries. On the temperate species sample, 100 % of ring porous wood species are found deciduous. The tropical species with ring porous wood are also mainly deciduous. As these wood features are frequently preserved in fossil specimens, this could be an interesting marker of vegetation type. This could be used to infer the seasonality of the paleoclimate.
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Dates et versions

hal-03665584 , version 1 (11-05-2022)

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  • HAL Id : hal-03665584 , version 1

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Anais A Boura, Dario De Franceschi. Is porous wood structure exclusive of deciduous trees ?. Congrès Paléobotanique et Evolution du monde végétal : quelques problèmes d’actualité, May 2007, Paris, France. ⟨hal-03665584⟩
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