Selective logging, fragmentation, and understory fires directly degrade forest structure and composition. However, studies addressing the effects of forest degradation on carbon, water, and energy cycles are scarce. Here, we integrate field observations and high‐resolution remote sensing from airborne lidar to provide realistic initial conditions to the Ecosystem Demography Model (ED‐2.2) and investigate how disturbances from forest degradation affect gross primary production (GPP), evapotranspiration (ET), and sensible heat flux (H). We used forest structural information retrieved from airborne lidar samples (13,500 ha) and calibrated with 817 inventory plots (0.25 ha) across precipitation and degradation gradients in the eastern Amazon as initial conditions to ED‐2.2 model. Our results show that the magnitude and seasonality of fluxes were modulated by changes in forest structure caused by degradation. During the dry season and under typical conditions, severely degraded forests (biomass loss ≥66%) experienced water stress with declines in ET (up to 34%) and GPP (up to 35%) and increases of H (up to 43%) and daily mean ground temperatures (up to 6.5°C) relative to intact forests. In contrast, the relative impact of forest degradation on energy, water, and carbon cycles markedly diminishes under extreme, multiyear droughts, as a consequence of severe stress experienced by intact forests. Our results highlight that the water and energy cycles in the Amazon are driven by not only climate and deforestation but also the past disturbance and changes of forest structure from degradation, suggesting a much broader influence of human land use activities on the tropical ecosystems.

中文翻译：

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退化对亚马逊热带森林水，能源和碳循环的影响

选择性伐木，破碎和林下火灾直接降低了森林的结构和组成。但是，关于森林退化对碳，水和能量循环的影响的研究很少。在这里，我们将机载激光雷达的实地观测和高分辨率遥感相结合，为生态系统人口模型（ED-2.2）提供现实的初始条件，并研究森林退化带来的干扰如何影响总初级生产力（GPP），蒸散（ET），和显热通量（H）。我们使用从机载激光雷达样本（13,500公顷）中获取的森林结构信息，并通过817个清单样地（0.25公顷）对亚马逊东部地区降水和退化梯度的校准，将其作为ED-2.2模型的初始条件。我们的结果表明，通量的大小和季节性受退化引起的森林结构变化的调节。在干旱季节和典型条件下，森林严重退化（生物量损失≥66％）经历了水分胁迫，相对于完好无损的ET（最多34％）和GPP（最多35％）下降，H（最高43％）和日平均地温（最高6.5°C）下降森林。相反，由于完好森林遭受的严重压力，在极端的多年干旱下，森林退化对能源，水和碳循环的相对影响显着减少。我们的研究结果表明，亚马逊地区的水和能源循环不仅受气候和森林砍伐的影响，还受退化造成的过去干扰和森林结构变化的影响，这表明人类土地利用活动对热带生态系统的影响更大。