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分散的树木死亡导致加利福尼亚州大量森林丧失
Yan Cheng1, Stefan Oehmcke2, Martin Brandt3
1Department of Geosciences and Natural Resource Management, University of Copenhagen, Copenhagen, Denmark. yach@ign.ku.dk.
Nature communications
|January 20, 2024
概括
加利福尼亚州加利福尼亚州加利福尼亚州.
科学领域:
- 森林生态 森林生态
- 遥感 遥感 遥感 遥感
- 气候变化影响 气候变化影响
背景情况:
- 全球变化推动了全球大规模的树木死亡事件.
- 现有的森林监测方法经常错过分散或孤立的枯树,导致死亡程度的不确定性.
- 准确评估个体树木死亡率对于了解森林健康和碳动态至关重要.
研究的目的:
- 用高分辨率的空中图像绘制整个加利福尼亚州的单独死树的地图.
- 量化分组和孤立树木死亡率的程度.
- 评估广泛的个体树木死亡对森林生态系统的影响.
主要方法:
- 使用了2020年以次米分辨率拍摄的空中照片.
- 采用深度学习算法来自动检测死树.
- 将结果与现场数据进行比较,以估计低估偏差.
主要成果:
- 在27.8万公的加利福尼亚植被地区识别了9140万棵枯树.
- 发现有1950万棵枯树被隔离,60%发生在小组中 (每格≤3棵树).
- 与现场数据相比,检测到显著的低估偏差 (16.724.7%).
结论:
- 广泛的单个树木死亡,包括分散的和小群体,是加利福尼亚森林的一个重要问题.
- 这种死亡率会影响森林碳预算和封存能力.
- 单个树木的死亡对森林健康构成威胁,增加了野火风险.
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