Forest biomass plays an important role in the global carbon cycle. Therefore, understanding the factors that control forest biomass stocks and dynamics is a key challenge in the context of global change. We analyzed data from 60 forest plots in the subtropical Andes (22–27.5° S and 300–2300 m asl) to describe patterns and identify drivers of aboveground biomass (AGB) stocks and dynamics. We found that AGB stocks remained roughly constant with elevation due to compensating changes in basal area (which increased with elevation) and plot‐mean wood specific gravity (which decreased with elevation). AGB gain and loss rates both decreased with elevation and were explained mainly by temperature and rainfall (positive effects on both AGB gains and losses). AGB gain was also correlated with forest‐use history and weakly correlated with forest structure. Mean annual temperature and rainfall showed minor effects on AGB stocks and AGB change (gains minus losses) over recent decades. Although AGB change was only weakly correlated with climate variables, increases in AGB gains and losses with increasing rainfall—together with observed increases in rainfall in the subtropical Andes—suggest that these forests may become increasingly dynamic in the future.

中文翻译：

---

亚热带安第斯山脉的森林生物量存量和动态

森林生物量在全球碳循环中起着重要作用。因此，在全球变化的背景下，了解控制森林生物量存量和动态的因素是一项关键挑战。我们分析了亚热带安第斯山脉（22-27.5°S和300-2300 m asl）的60个森林地块的数据，以描述模式并确定地上生物量（AGB）储量和动态的驱动因素。我们发现，由于补偿了基础面积（随海拔升高而增加）和积土平均木材比重（随海拔升高而降低）的变化，AGB积木随海拔升高大致保持恒定。AGB得失率均随海拔升高而下降，并且主要由温度和降雨解释（对AGB得失均有正影响）。AGB的增加也与森林使用历史相关，而与森林结构之间的相关性较弱。在过去的几十年中，年均温度和降雨对AGB存量和AGB的变化影响很小（收益减去损失）。尽管AGB的变化与气候变量之间的关系很小，但随着降雨的增加，AGB得失的增加（连同在亚热带安第斯山脉观测到的降雨量的增加）表明，这些森林将来可能变得越来越活跃。