401. The hydraulic performance of tropical rainforest trees in their perhumid environment - is there evidence for drought vulnerability?
- Author
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Viviana Horna, Bernhard Schuldt, Soekisman Tjitrosemito, Alexandra Zach, and Christoph Leuschner
- Subjects
0106 biological sciences ,Abiotic component ,Hydrology ,biology ,Ecology ,Vapour Pressure Deficit ,Xylem ,15. Life on land ,biology.organism_classification ,010603 evolutionary biology ,01 natural sciences ,Twig ,Geography ,Species level ,Hydraulic conductivity ,Castanopsis acuminatissima ,010606 plant biology & botany ,Tropical rainforest - Abstract
In a species-rich perhumid tropical rainforest of Central Sulawesi, Indonesia, we studied the hydraulic properties of eight representative tree species and searched for evidence that analyzing hydraulic patterns at the species level provides valuable information to understand the role of abiotic drivers and structural parameters in controlling plant water consumption.We investigated the relationship between xylem hydraulic properties and tree size with the aim to determine possible hydraulic plasticity in response to the vertical variation in environmental conditions in an otherwise constantly humid forest.We found leaf-specific (LSC) and sapwood-area specific (kS) hydraulic conductivity of twigs to significantly increase with tree height across species. The marked increase of LSC and kS with tree height was closely coupled with an increase in mean vessel diameters and this trend was consistent for both, stem and twig xylem. Rates of xylem sap flow (J) of all tree species were strongly positively related to atmospheric vapor pressure deficit (VPD) and radiation (R), when evaluated on a daily basis. However, J started to level off at VPD values of about 0.4 kPa in trees of all size classes. We therefore concluded that the stomatal response of tropical moist forest trees is very sensitive to changes in the atmospheric evaporative demand. more...
- Published
- 2010
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