Over time, carbon sequestered in temperate forests has increased, but the relative effects of passive and active drivers remain unclear. This study uses plot-level data to disentangle the contributions of six drivers (temperature, precipitation, CO 2 , management, age composition, and area) to these increases in 14 forest groups of the conterminous United States. From 2005 to 2022, the passive drivers (CO 2 , temperature, and precipitation) increased live tree carbon (C) by 66 teragrams (Tg) C y −1 with CO 2 fertilization contributing most of the change. Among the anthropogenic drivers, declining forest area reduced live tree C by 31 Tg C y −1 while tree planting increased it by 23 Tg C y −1 . Changes in age composition, driven by both passive traits and anthropogenic choices, increased live tree C by 89 Tg C y −1 . By quantifying the share of removals attributable to passive uptake, this approach enables nations with national forest inventories to better utilize their forests to meet net-zero requirements.
Davis et al. (2026) studied this question.