Forest dynamics are driven by a myriad of factors and link directly to ecosystem services. The dynamics of the highly degraded Brazilian Atlantic Forest (AF) hotspot is mostly driven by its anthropogenic context. Currently, most of the AF region is composed of small disturbed secondary forest fragments that have received partial or full environmental protection with recent environmental norms. Such protection prevents further disturbances and consequently shifts the course of forest dynamics and ecosystem services in AF. Here, we assess long-term forest dynamics trends of a small secondary AF fragment to test the hypothesis that disturbed AF fragments are reaching advanced successional stages. We used a unique dataset of 126 permanent subplots (totaling 5.04 ha) monitored for 30 years (8 inventories between 1987 and 2017) of a disturbed secondary AF fragment (6.35 ha) that has been fully protected since 1986. In each inventory, we measured all living trees with a diameter at breast height (DBH) ≥ 5 cm and counted survivors, recruits and dead individuals between intervals. We monitored the temporal trends of (i) structural variables (biomass, tree density and species richness), (ii) functional composition (wood density and maximum potential size), (iii) and species dominance. Our results indicate that, now under full protection, the fragment is shifting towards a late successional stage: we observed increasing biomass, decreasing tree density (self-thinning) and increasing abundance of late-successional species with conservative strategies. Species richness and dominant species composition were stable throughout the monitoring period, suggesting an absence of substantial changes in community assembly. These results underscore the role played by small secondary AF fragments in ecosystem service provision (e.g., carbon uptake and shelter for biodiversity) and point to their forest dynamics trends.

森林动态受到多种因素的驱动，并直接与生态系统服务联系在一起。高度退化的巴西大西洋森林（AF）热点的动力学主要是由其人为背景驱动的。当前，大部分的AF区域都是由受干扰的小型次生森林碎片组成的，这些碎片已经按照最近的环境规范获得了部分或全部环境保护。这样的保护可以防止进一步的干扰，从而改变AF中森林动态和生态系统服务的进程。在这里，我们评估了一个小的次生AF片段的长期森林动态趋势，以检验扰乱的AF片段已到达高级演替阶段的假说。我们使用了126个永久子图的唯一数据集（总计5个）。（04公顷）监测了受干扰的次生AF片段（6.35公顷）的30年（1987年至2017年之间有8份清单），该碎片自1986年以来已得到完全保护。在每个清单中，我们测量了所有直径与胸高相同的活树（DBH） ）≥5厘米，并计算间隔之间的幸存者，新兵和死亡人数。我们监测（i）结构变量（生物量，树木密度和物种丰富度），（ii）功能成分（木材密度和最大潜在大小），（iii）和物种优势的时间趋势。我们的结果表明，在完全保护的情况下，该碎片正在向后期演替阶段转移：我们观察到采用保守策略增加了生物量，降低了树木密度（自稀疏），并增加了后继物种的丰度。在整个监测期内，物种丰富度和优势物种组成保持稳定，这表明社区集会没有实质性变化。这些结果强调了小型次生AF片段在生态系统服务提供中的作用（例如，碳吸收和生物多样性的庇护所），并指出了它们的森林动态趋势。