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Description
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Abstract Catchment-scale transpiration is commonly determined by the use of sap-flow sensors, and its quantification, which is critical for water and forest management, relies crucially on the total catchment’s sapwood area (A s ). Species-specific allometric relationships between the trees A s and the trees diameter at breast height (DBH) are widely used for determining stand or catchment A s . However, substantial differences between studies challenged the robustness of these relationships between sites displaying various topographical and environmental characteristics. In this study, we aim at comparing these relationships between species of the Quercus genus from sites in different parts of the world, and testing the role of topographical factors on A s -DBH relationship in Quercus petraea . Using 145 trees sampled within a 0.455 km² catchment, we showed that topography (slope, flow accumulation, aspect, curvature, topographic wetness index) does not modulate the A s -DBH relationship in Quercus petraea , within our catchment. We compared our curve parameters with the ones from 17 studies on oak trees and found that the A s -DBH relationship is not only species-specific, but depends on the site’s conditions, and likely the stand density, the total radiation and the evaporative demand. In the light of these results, we recommend to build site- and species-specific A s -DBH relationship for determining stand transpiration, using a minimum of nine, randomly sampled trees, and different methods and azimuthal directions for determining sapwood depth. (2022-06-16)
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Keyword
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Transpiration, Diameter at breast height, Quercus petraea, Drainage basin, Allometry, Environmental science, Ecology, Hydrology (agriculture), Geography, Biology, Botany, Geology, Cartography |
