Exotic forest insects and pathogens (EFIP) have become regular features of temperate forest ecosystems, yet we lack a long-term perspective on their net impacts on tree mortality, carbon sequestration, and tree species diversity. Here, we analyze 3 decades (1987–2019) of forest monitoring data from the Blue Ridge Mountains ecoregion in eastern North America, including 67 plots totaling 29.4 ha, along with a historical survey from 1939. Over the past century, EFIP substantially affected at least eight tree genera. Tree host taxa had anomalously high mortality rates (≥ 6% year⁻¹ from 2008 to 2019 vs 1.4% year⁻¹ for less-impacted taxa). Following the arrival of EFIP, affected taxa declined in abundance (− 25 to − 100%) and live aboveground biomass (AGB; − 13 to − 100%) within our monitoring plots. We estimate that EFIP were responsible for 21–29% of ecosystem AGB loss through mortality (− 87 g m⁻² year⁻¹) from 1991 to 2013 across 66 sites. Over a century, net AGB loss among affected species totaled roughly 6.6–10 kg m⁻². The affected host taxa accounted for 23–29% of genera losses at the plot scale, with mixed net effects on α-diversity. Several taxa were lost from our monitoring plots but not completely extirpated from the region. Despite these losses, both total AGB and α-diversity were largely recovered through increases in sympatric genera. These results indicate that EFIP have been an important force shaping forest composition, carbon cycling, and diversity. At the same time, less-affected taxa in these relatively diverse temperate forests have conferred substantial resilience with regard to biomass and α-diversity.

外来森林昆虫和病原体（EFIP）已成为温带森林生态系统的常规特征，但是我们对其外来物种对树木死亡率，碳固存和树木物种多样性的净影响尚缺乏长期观点。在这里，我们分析了来自北美东部蓝岭山脉生态区的3年（1987-2019年）森林监测数据，包括67块土地，总计29.4公顷，以及1939年的历史调查。在过去的一个世纪中，EFIP对至少八棵树属。树木寄主分类群的死亡率异常高（2008年至2019年≥6％- ¹年，而1.4％- ^1年受影响较小的分类单元）。随着EFIP的到来，在我们的监测范围内，受影响的分类单元数量减少了（− 25至− 100％），并降低了地上生物量（AGB； − 13至− 100％）。我们估计，从1991年到2013年，EFIP造成了66个地点的生态系统AGB通过死亡率（-87 g m ^-2  year ^-1）损失了21-29％。一个多世纪以来，受影响物种中的AGB净损失总计约为6.6-10 kg m ^-2。在样地尺度上，受影响的寄主分类单元占总属损失的23–29％，而对α多样性的混合净影响则较大。我们的监测区失去了几个分类单元，但并未从该地区完全灭绝。尽管有这些损失，但总AGB和α-通过增加同胞属，很大程度上恢复了多样性。这些结果表明，EFIP已成为影响森林组成，碳循环和多样性的重要力量。同时，在这些相对多样化的温带森林中，受影响较小的分类单元在生物量和α-多样性方面赋予了很大的适应力。