The importance of populations of the Socotra dragon’s blood trees (Dracaena cinnabari Balf.f., 1882) for horizontal precipitation capture was estimated for the first time. Dragon’s blood trees (Asparagaceae) inhabit semiarid cloud forests with low levels of rainfall that strongly depend on additional moisture from fog and clouds. Our estimation was based on a detailed description of the aboveground biomass structure of stands of the dragon’s blood trees on Socotra Island. The aboveground biomass was described using non-destructive methods. An example of a well-preserved forest was measured in terms of the basic biometric characteristics of each tree, and the trees were divided into three classes based on crown projections. For each class, we took detailed measurements of one representative tree. All measured and counted growth characteristics were converted to the stand level. The tree population at the whole island level was investigated using remotely sensed data. The estimation of horizontal precipitation was performed using detailed and precise evaluation of the available climate data in half-hour intervals over the period of June 2009 and June 2010 and the ambulatory direct measurements (12.6.2009–26.6.2009). The mean annual horizontal precipitation below the crown of the dragon’s blood tree was estimated to be 792 mm in the highest (951–1545 m a.s.l.), 373 mm in the middle (601–950 m a.s.l.) and 46 mm in the lowest (180–600 m a.s.l.) altitudinal zones. Our model showed that the horizontal precipitation exceeded 40% of the total annual precipitation. The decline in the dragon’s blood tree forest could therefore cause the loss of additional water from the island’s hydrological cycle.

中文翻译：

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索科特拉岛的血树，云雾森林和林地对于捕获水平降水的潜在重要性

索科特拉岛龙血树（Dracaena cinnabari）的重要性1882年在Balf.f.首次估算了水平降水。龙血树（芦笋科）居住在半干旱的云雾森林中，降雨水平低，这主要取决于雾气和云雾中的额外水分。我们的估算是基于对索科特拉岛上龙血树的地上生物量结构的详细描述。使用非破坏性方法描述了地上生物量。根据每棵树的基本生物特征，测量了一个保存完好的森林的例子，并根据树冠投影将树木分为三类。对于每一堂课，我们对一棵代表性树进行了详细的测量。将所有测量和计数的生长特性转换为林分水平。使用遥感数据调查了整个岛屿一级的树木种群。水平降水的估算是通过对2009年6月和2010年6月半小时的可用气候数据进行详细而精确的评估以及动态直接测量（12.6.2009–26.6.2009）进行的。据估计，龙血树冠下的年平均水平降水量最高（951-1545 m asl）为792毫米，中间（601-950 m asl）为373毫米，最低（180 asl为46毫米）。 –600 m asl）垂直区域。我们的模型表明，水平降水超过了年总降水量的40％。因此，龙血树森林的减少可能会导致该岛的水文循环损失更多的水。