Aboveground biomass in mature and secondary seasonally dry tropical forests: A literature review and global synthesis

Seasonally dry tropical forests (SDTFs) are globally extensive but understudied, especially from a biogeochemical perspective. Historically, much of the land covered by SDTF has been cleared for agriculture or other land uses, but forests are now regenerating in some areas. Quantifying biomass stocks in mature and regenerating SDTF is important for constructing global carbon budgets and for designing local policy and management tools designed to sequester and store carbon. We reviewed 44 published and unpublished studies that estimate aboveground biomass in SDTF around the world and examined patterns of biomass across successional stages and the climatic range in which SDTF occur. Aboveground biomass in mature SDTF ranged from 39 to 334 Mg ha−1. A single climatic variable, mean annual precipitation (MAP), explained over 50% of the variation in aboveground biomass. Regenerating SDTFs at the wetter end of the precipitation spectrum (1500–2000 mm MAP) attained a greater biomass but did not appear to reach maximum biomass faster than SDTFs at drier sites. We used spatially explicit biomass, climate, and biome range data along with the derived precipitation-biomass relationship to estimate current and potential global SDTF biomass C stocks of 8.7 and 22.1 Pg respectively.

► Biomass in seasonally dry tropical forest is globally significant but poorly characterized.
► We combined data from 44 studies of aboveground biomass in seasonally dry tropical forest.
► Mean annual precipitation explains 55% of variation in mature forest biomass.
► Precipitation affects the maximum biomass attained by recovering secondary forests.