Although deforestation remains widespread in the tropics, many places are now experiencing significant forest recovery (i.e., forest transition), offering an optimistic outlook for natural ecosystem recovery and carbon sequestration. Naturally regenerated forests, however, may not persist, so a more nuanced understanding of the drivers of forest change in the tropics is critical to ensure the success of reforestation efforts and carbon sequestration targets. Here we use 35 years of detailed land cover data to investigate forest trajectories in 3014 municipalities in the Brazilian Atlantic Forest (AF), a biodiversity and conservation hotspot. Although deforestation was evident in some regions, deforestation reversals, the typical forest transition trajectory, were the prevalent trend in the AF, accounting for 38% of municipalities. However, simultaneous reforestation reversals in the region (13% of municipalities) suggest that these short-term increases in native forest cover do not necessarily translate into persistent trends. In the absence of reversals in reforestation, forests in the region could have sequestered 1.75 Pg C, over three times the actual estimated carbon sequestration (0.52 Pg C). We also showed that failure to distinguish native and planted forests would have masked native forest cover loss in the region and overestimated reforestation by 3.2 Mha and carbon sequestration from natural forest regeneration by 0.37 Pg C. Deforestation reversals were prevalent in urbanized municipalities with limited forest cover and high agricultural productivity, highlighting the importance of favorable socioeconomic conditions in promoting reforestation. Successful forest restoration efforts will require development and enforcement of environmental policies that promote forest regeneration and ensure the permanence of regrowing forests. This is crucial not only for the fate and conservation of the AF, but also for other tropical nations to achieve their restoration and carbon sequestration commitments.

中文翻译：

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短暂的森林再生限制了巴西大西洋森林的碳封存潜力

尽管热带地区的森林砍伐仍然普遍，但许多地方现在正在经历显着的森林恢复（即森林转型），为自然生态系统恢复和碳固存提供了乐观的前景。然而，自然再生的森林可能不会持续存在，因此对热带森林变化的驱动因素有更细致的了解对于确保重新造林努力和碳固存目标的成功至关重要。在这里，我们使用 35 年的详细土地覆盖数据来调查巴西大西洋森林 (AF) 中 3014 个城市的森林轨迹，这是一个生物多样性和保护热点。尽管森林砍伐在一些地区很明显，但森林砍伐逆转，典型的森林过渡轨迹，是 AF 的普遍趋势，占城市的 38%。然而，该地区（13% 的城市）同时重新造林的逆转表明，本地森林覆盖率的这些短期增加并不一定会转化为持续的趋势。在重新造林没有逆转的情况下，该地区的森林可以固存 1.75 Pg C，是实际估计的碳固存量 (0.52 Pg C) 的三倍多。我们还表明，未能区分原生林和人工林将掩盖该地区原生森林覆盖的损失，并高估了 3.2 Mha 的重新造林和 0.37 Pg C 的天然林再生碳固存。森林覆盖率有限的城市化城市普遍存在森林砍伐逆转和高农业生产力，突出了有利的社会经济条件在促进重新造林方面的重要性。成功的森林恢复工作将需要制定和执行促进森林再生并确保再生森林永久性的环境政策。这不仅对于 AF 的命运和保护至关重要，而且对于其他热带国家实现其恢复和固碳承诺也至关重要。