Estimating Individual Tree Mortality in the Sierra Nevada Using Lidar and Multispectral Reflectance Data
Estimating Individual Tree Mortality in the Sierra Nevada Using Lidar and Multispectral Reflectance Data
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使用激光雷达和多光谱反射数据估计内华达山脉的单棵树死亡率
DOI：
10.1029/2022jg007234
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发表时间：
2023
期刊：
影响因子：
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通讯作者：
Randerson, J. T.
中科院分区：
文献类型：
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作者：
Hemming‐Schroeder, N. M.;Gutierrez, A. A.;Allison, S. D.;Randerson, J. T.
广泛的树木死亡事件发生在温带针叶林严重干旱期间，由于气候变化，预计在许多地区将变得更加频繁。需要改进单个树木死亡率的制图，以确定风险因素和设计有效的保护策略。在这项研究中，我们使用国家生态观测站网络（NEON）激光雷达和多光谱反射机载观测，绘制了2012-2016年干旱期间和之后160平方公里范围内的单个树木死亡率。我们使用NEON激光雷达获得树木位置和树冠周长，并使用多光谱数据绘制100多万棵树木的死亡率图。我们发现，在2013年至2017年期间，研究区域有25.4%的树木死亡，其中海拔较低的Soaproot Saddle地区的死亡率要高得多。在2017年至2019年期间，每年有2.0%-2.8%的树木死亡。2020年和2021年的两场野火使2019年至2021年期间被烧毁区域内的树木死亡率增加了49%-89%。与之前的工作一致，我们发现树木死亡风险随着树高的增加而增加。在低海拔样地，树木死亡率与离河距离、每公顷乔木数和坡度递减呈正相关。坡度越高，树木死亡率越高。我们的方法和数据集为研究干旱和野火对树木死亡率的综合影响提供了一种方法，并可能改善气候变化下森林恢复力的预测。
Widespread tree mortality events occur during periods of severe drought in temperate conifer forests and are expected to become more frequent in many areas due to climate change. Improved mapping of individual tree mortality is needed to identify risk factors and design effective conservation strategies. In this study, we used National Ecological Observatory Network (NEON) lidar and multispectral reflectance airborne observations to map individual tree mortality over a 160 km2area during and after the 2012–2016 drought for two sites in California's Sierra National Forest. We used NEON lidar to derive tree locations and crown perimeters and multispectral data to map tree mortality for more than 1 million trees. We found that 25.4% of the trees in our study area died between 2013 and 2017, with considerably higher mortality at the lower‐elevation Soaproot Saddle site. Between 2017 and 2019, an additional 2.0%–2.8% of the trees died each year. Two wildfires in 2020 and 2021 increased tree mortality within burned area perimeters by 49%–89% between 2019 and 2021. Consistent with previous work, we found that tree mortality risk increased as a function of tree height. Tree mortality was positively associated with distance from rivers, trees per hectare, and decreasing slope at the lower elevation site. In contrast, increasing slope was positively associated with tree mortality at the higher elevation site. Our approach and dataset provide a means to study the combined effects of drought and wildfire on tree mortality and may improve projections of forest resilience under a changing climate.
影响因子：
5
作者：
Byer, Sarah;Jin, Yufang
通讯作者：
Jin, Yufang
内华达山脉南部干旱期间树木死亡的原因是什么？
DOI：
10.1002/eap.1620
发表时间：
2017
期刊：
Ecological applications : a publication of the Ecological Society of America
影响因子：
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作者：
T. Paz;P. Brodrick;N. Vaughn;Adrian J. Das;N. Stephenson;K. Nydick;G. Asner
通讯作者：
G. Asner