Amazon forest response to droughts, fire, and land use: a multi-scale approach to forest dieback

亚马逊森林占地球上所有热带雨林的很大一部分。这些森林影响全球碳和水循环，从而影响全球气候系统。在过去的几十年里，亚马逊森林因干旱、伐木活动、森林火灾和森林砍伐而严重改变或退化。在不久的将来，随着热带地区气候的变化，森林火灾的频率可能会增加。然而，考虑到当前和预测的土地利用和气候变化趋势，预测热带森林潜在轨迹的能力非常有限。在这项研究中，航空和卫星遥感将与统计模型相结合，预测亚马逊树的死亡，这是一个重要的生态过程，影响森林总碳积累和储存、物种多样性、小气候特征和水流。这项研究将考虑到包括火灾、伐木和干旱在内的干扰，以及秘鲁Madre de Dios高多样性地区的土壤肥力和植物特征。虽然以前的研究试图建立热带森林的树木死亡模型，但大多数研究要么受到野外样本量较小的限制，要么缺乏地理覆盖和空间细节。因此，这项研究的创新之处在于，使用航空测量绘制出整个景观中个体树木的死亡地图，然后结合卫星和建模方法，扩大到更大的区域水平。这项研究将为美国国际开发署的美国可持续景观计划做出贡献，该计划正在支持热带国家旨在减少森林砍伐和森林退化造成的碳排放的计划。该项目还将培养两名美国博士生、三名拉丁美洲研究生和六名本科生。

Amazon forests make up a large fraction of all tropical forests on Earth. These forests influence the global carbon and water cycles and, therefore, the global climate system. In past decades, Amazonian forests have been severely altered or degraded by droughts, logging activities, forest fires, and deforestation. In the near future, forest fires may increase in frequency as the climate changes in tropical regions. However, there is very limited capacity to predict the potential trajectories of tropical forests given current and projected trends in land use and climate change.In this study, airborne and satellite remote sensing will be combined with statistical models to predict Amazon tree mortality, an important ecological process that influences total forest carbon accumulation and storage, species diversity, microclimate characteristics, and water flow. The study will account for disturbances including fires, logging and droughts, as well as soil fertility and plant characteristics in the high diversity region of Madre de Dios, Peru. While previous studies have attempted to develop tree mortality models for tropical forests, most of them either have been limited by small field-based sample sizes, or they lack geographic coverage and spatial detail. The novelty of this study, therefore, is to map mortality of individual trees across the landscape using airborne measurements, then to scale up to the larger regional level using a combination of satellite and modeling approaches.This study will contribute to the US Sustainable Landscape program of the U.S. Agency for International Development that is supporting programs in tropical nations designed to reduce emissions of carbon from deforestation and forest degradation. The project will also train two American doctoral students, three Latin American graduate students, and six undergraduates.