Small vegetation biomass retention efficiency across global forests

Live forest biomass is essential in sequestering carbon and supporting ecosystem services. How much of the synthesized biomass ultimately stays in live plant biomass remain elusive. Here we propose a new proxy, biomass retention efficiency (BRE), to measure the efficiency of biosynthesized carbohydrates remained in live plant biomass in forests. Based on satellite measurements and terrestrial ecosystem models, we estimated that globally the median of BRE goes from 0.21% to 2.60%, much smaller than carbon use efficiency and biomass production efficiency (ca. 50%). Across forest types, BREs derived from different datasets exhibit inconsistent patterns. This large differences mainly stems from the inconsistency in quantifying biomass changes across different approaches. This small BRE highlights the importance of tracking the fate of nonliving biomass carbon for better understanding forest carbon sequestration, and the uncertainties emphasize the needs for coordinated effort for future improvements in high-quality large-scale biomass estimation and model-data integration. Only 0.2–2.6% of synthesized biomass stays in live plants at the global scale, as revealed by biomass retention efficiency, a newly developed metric based on satellite data and ecosystem models.