Leaf chlorophyll content declines in response to environmental stressors and during natural senescence periods. Assessments of forest health and vulnerability to stressors require repeated measurements of forest health to quantify declines in chlorophyll content and identify shifts in the timing of key phenological events. Although remote sensing is ideal for making reliable and repeated forest health measurements to assess forest response to environmental change over large areas, reliable warning systems for monitoring plant health are lacking. To facilitate the estimation of chlorophyll content from remotely sensed data, we define the relationships between leaf chlorophyll content and spectral indices in European beech trees ( Fagus sylvatica ). We show that hand-held chlorophyll meters can be calibrated to leaf chlorophyll content providing a non-destructive method for rapid assessment of leaf chlorophyll content in the field. Spectral indices based on the red edge spect...

中文翻译：

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欧洲山毛榉树叶片衰老过程中叶绿素含量的光谱响应

叶片的叶绿素含量响应环境胁迫和自然衰老期而下降。对森林健康和对压力胁迫的脆弱性进行评估需要对森林健康进行重复测量，以量化叶绿素含量的下降并确定关键物候事件发生时间的变化。尽管遥感是进行可靠且重复的森林健康测量以评估森林对大面积环境变化的反应的理想选择，但仍缺乏用于监测植物健康的可靠预警系统。为了便于从遥感数据中估算叶绿素含量，我们定义了欧洲山毛榉树（Fagus sylvatica）中叶绿素含量与光谱指数之间的关系。我们显示，手持式叶绿素仪可以校准为叶绿素含量，为现场评估叶绿素含量提供了一种非破坏性方法。基于红边光谱的光谱指数...