For whom
Employees, Alumni
01-09-2017 from 12:00 to 13:00
Room A2.097, Campus Coupure, Coupure Links 653, Ghent
Kathy Steppe
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SAPFLUXNET: Compiling sap flow data from around the world to unravel how plants regulate transpiration
by Dr. Rafael Poyatos, CREAF (Centre for Ecological Research and Forestry Applications), Barcelona, Spain


Plant transpiration is the fundamental process linking water and vegetation, and is therefore a central topic in ecohydrological research. Plants regulate transpiration in response to fluctuations of water demand and supply at multiple temporal scales. Physiological regulation of transpiration also underlies drought responses of plants, and is a key process in understanding the patterns of drought-induced tree mortality.

Sap flow in plant stems, measured with thermometric methods, reveals the temporal patterns of these responses. However, even though sap flow methods have been widely used since the 1990s, sap flow data have remained fragmentary and generally unavailable for syntheses of regional to global scope.

SAPFLUXNET ( is the first global database of sap flow measurements from individual plants, contributed by researchers worldwide. SAPFLUXNET has > 150 datasets, covers most vegetated biomes and holds data for > 1500 individual plants, mostly trees, belonging to > 100 species and > 50 genera. I will provide an overview of the data infrastructure behind SAPFLUXNET, designed to enable data harmonisation, archiving and reuse in the open data era.

Finally, I will pose some potential research questions that can be addressed using this database. For example, how do maximum transpiration rates vary with tree size properties such as tree diameter or leaf area? How do trees regulate transpiration as a function of water supply and evaporative demand worldwide? How can we use sap flow data to improve ecosystem water balance models? Finally, I will briefly present the potential of combining SAPFLUXNET with other global data sources of plant and ecosystem physiology.