Global Transpiration Data from Sap Flow Measurements: The SAPFLUXNET Database

A new global database of sap flow measurements for understanding and modeling plant water use.

A sap flux sensor on a pine tree.

A sap flux sensor on a pine tree in a Mediterranean forest (Can Balasc, Barcelona, Spain). The sensor heats the trunk and measures temperature differences in the sapwood to estimate sap flux.

[Courtesy Centre for Research on Ecology and Forestry Applications.]

The Science

Despite how critical plant water use is to biology, ecology, and biogeochemistry, its response to global change is currently not well understood. Plant sap flux, a measure of water use, links vegetation with the water, energy, and carbon budgets of terrestrial ecosystems.  Here, scientists introduced the first global compilation of whole-plant water use data from sap flux measurements, combining efforts of 164 scientists to generate a global database of sap flux measurements (SAPFLUXNET). The dataset and associated open-source code are publicly available.

The Impact

SAPFLUXNET will enable scientific understanding of the climatic, ecological, and biological factors driving plant water use across the globe, and open up new frontiers of research into the water cycle. SAPFLUXNET contains 202 globally distributed datasets with sap flux time series for 2,714 plants across 174 species. This dataset provides the first global benchmark of plant water use for model testing, and adds to advance understanding of water resource use and conservation globally.


Tree water use is the dominant movement of water in the water cycle and is critical for accurate predictive models of water, carbon, and energy budgets. A large collaboration of scientists brought together a globally distributed set of existing tree water use datasets and assembled 202 sites with sap flux data. All datasets were quality controlled and integrated with additional site-specific datasets of local meteorology and tree physiology. Open-source R-code was generated to enable independent scientists to extract and process data, and all aspects of the dataset were made publicly available. Through provision of this global database, discovery of new controls over vegetation water use can be achieved. Ultimately, this database will rapidly advance scientists’ ability to understand and predict not only the role of vegetation in the water cycle but also the role of water use in plant growth and survival.

Principal Investigator

Rafael Poyatos
Centre for Research on Ecology and Forestry Applications, Barcelona, Spain

Program Manager

Brian Benscoter
U.S. Department of Energy, Biological and Environmental Research (SC-33)
Environmental System Science


Nate McDowell was supported as part of the Next Generation Ecosystem Experiments–Tropics (NGEE–Tropics) project, funded by the Biological and Environmental Research (BER) Program within the U.S. Department of Energy’s (DOE) Office of Science, under DOE contract to Pacific Northwest National Laboratory (PNNL). Additional funding was provided by the Ministerio de Economía y Competitividad (grant no. CGL2014-55883-JIN); the Ministerio de Ciencia e Innovación (grant no. RTI2018-095297-J-I00); the Ministerio de Ciencia e Innovación (grant no. CAS16/00207); the Agència de Gestió d’Ajuts Universitaris i de Recerca (grant no. SGR1001); the Alexander von Humboldt-Stiftung (Humboldt Research Fellowship for Experienced Researchers [RP]); and the Institució Catalana de Recerca i Estudis Avançats (Academia Award [JMV]). Víctor Flo was supported by the doctoral fellowship FPU15/03939 (MECD, Spain).

Related Links


Poyatos, R., et al. "Global Transpiration Data from Sap Flow Measurements: The SAPFLUXNET Database." Earth System Science Data 13 (6), 2607–2649  (2021).