Image credit: ESSD

Global transpiration data from sap flow measurements: the SAPFLUXNET database

Image credit: ESSD

Global transpiration data from sap flow measurements: the SAPFLUXNET database

Abstract

Plant transpiration links physiological responses of vegetation to water supply and demand with hy-drological, energy, and carbon budgets at the land–atmosphere interface. However, despite being the main landevaporative flux at the global scale, transpiration and its response to environmental drivers are currently notwell constrained by observations. Here we introduce the first global compilation of whole-plant transpirationdata from sap flow measurements (SAPFLUXNET, https://sapfluxnet.creaf.cat/, last access: 8 June 2021). Weharmonized and quality-controlled individual datasets supplied by contributors worldwide in a semi-automaticdata workflow implemented in the R programming language. Datasets include sub-daily time series of sap flowand hydrometeorological drivers for one or more growing seasons, as well as metadata on the stand charac-teristics, plant attributes, and technical details of the measurements. SAPFLUXNET contains 202 globally dis-tributed datasets with sap flow time series for 2714 plants, mostly trees, of 174 species. SAPFLUXNET hasa broad bioclimatic coverage, with woodland/shrubland and temperate forest biomes especially well repre-sented (80 % of the datasets). The measurements cover a wide variety of stand structural characteristics andplant sizes. The datasets encompass the period between 1995 and 2018, with 50 % of the datasets being at least3 years long. Accompanying radiation and vapour pressure deficit data are available for most of the datasets,while on-site soil water content is available for 56 % of the datasets. Many datasets contain data for speciesthat make up 90 % or more of the total stand basal area, allowing the estimation of stand transpiration in di-verse ecological settings. SAPFLUXNET adds to existing plant trait datasets, ecosystem flux networks, andremote sensing products to help increase our understanding of plant water use, plant responses to drought,and ecohydrological processes. SAPFLUXNET version 0.1.5 is freely available from the Zenodo repository(https://doi.org/10.5281/zenodo.3971689; Poyatos et al., 2020a). The “sapfluxnetr” R package – designed toaccess, visualize, and process SAPFLUXNET data – is available from CRAN.

Publication
In Earth System Science Data