Dataset of annual and monthly nitrous oxide flux from global forests

The database of N₂O fluxes was constructed from published literature that was searched for using the keywords “nitrous oxide flux” and “forests” in the database of ISI Web of Science. The site-level N₂O flux data were compiled from articles published until 2018. The sites consist of natural or semi-natural forests, and samplings from economic forests were rejected to avoid the influence of human activity, and laboratory studies were not included. In addition, the chamber method was only selected in this database to avoid the uncertainties caused by different measurement techniques. Ultimately, a total of 191 records of annual N₂O fluxes from 99 published literatures were collected to form our database. Moreover, 112 sites in the database have monthly N₂O flux data, totaling 2,053 records. The species in our database were classified into different biotic forest groups (leaf traits (i.e., broad and coniferous, LT) and leaf habits (evergreen and deciduous, LH)), according to the information which selected from corresponding articles (e.g. dominant species). Geographic, climatic, vegetation, including latitude, longitude, soil type, vegetation type, climate variables (i.e., mean annual temperature and mean annual precipitation), and edaphic factors (e.g., soil dissolved organic carbon (DOC), ammonium concentration (NH₄⁺), nitrate concentration (NO₃^-), water filled pore space (WFPS) and soil temperature), were also collected from corresponding articles. For each site, we calculated the means of annual N₂O fluxes during the observation period, and the monthly values of N₂O fluxes were calculated based on the average of two or three daily fluxes obtained from corresponding articles. The daily N₂O flux dataset was extracted from the published figures and tables using GetData Graph Digitizer version 2.24. More information please contact Kerou Zhang ([e-mail]).