The objective of this short communication is to explore spatial distribution of soil suction in the vicinity of an urban tree considering effects of termite infestation and also radiant energy interception by canopy. A site in an urban landscape containing a mix of species cover (grass cover in the vicinity of trees) was selected for monitoring. A field monitoring program was designed to monitor soil (soil suction, moisture), vegetation parameters (tree height, grass leaf area), and meteorological parameters during drying/wetting cycles. As expected, before termite infestation, suction magnitude and rate of change were highest near the tree stem and at shallower depths, reflecting the dominance of transpiration over evaporation. However, after termite infestation, soil suction diminished significantly near the tree stem and increased farther from the tree stem, a phenomenon accompanied by loss of canopy area, as captured by a color analysis technique (i.e., an image processing method). These findings reflected a reduction in stomatal conductance, itself an indicator of transpiration loss through the stomata—likely because reduced canopy shading effects caused increased evaporation. Soil suction at deeper depths seemed not to be significantly affected, generally due to canopy and termite infestation. In summary, the study sheds new light on issues of tree maintenance by showing how termite infestation can significantly affect the performance of green infrastructure.

中文翻译：

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现场监测城市树木附近的吸力：探索白蚁的侵扰和树冠的遮蔽作用

这种简短交流的目的是考虑白蚁侵扰的影响以及冠层对辐射能的拦截，探索城市树木附近土壤吸力的空间分布。选择了城市景观中包含物种覆盖物（树木附近的草覆盖物）的场所进行监测。设计了一个野外监测程序来监测土壤（吸水，水分），植被参数（树高，草叶面积）和干燥/湿润周期中的气象参数。不出所料，在白蚁出没之前，靠近树干和较浅深度的吸力大小和变化率最高，反映出蒸腾作用高于蒸发作用。但是，白蚁出没后 土壤吸力在树茎附近显着减少，并在远离树茎处增加，这种现象伴随着冠层面积的减少，这是通过颜色分析技术（即图像处理方法）捕获的。这些发现反映了气孔导度的降低，气孔导度本身就是通过气孔蒸腾作用损失的指标，这很可能是由于冠层遮光作用的降低导致了蒸发的增加。通常由于冠层和白蚁侵扰，在更深的深度的土壤吸力似乎没有受到明显影响。总而言之，该研究通过显示白蚁侵扰如何严重影响绿色基础设施的性能，为树木的维护问题提供了新的思路。这些发现反映了气孔导度的降低，气孔导度本身就是通过气孔蒸腾作用损失的指标，这很可能是由于冠层遮光作用的降低导致了蒸发的增加。通常由于冠层和白蚁侵扰，在更深的深度的土壤吸力似乎没有受到明显影响。总而言之，该研究通过显示白蚁侵扰如何严重影响绿色基础设施的性能，为树木的维护问题提供了新的思路。这些发现反映了气孔导度的降低，气孔导度本身就是通过气孔蒸腾作用损失的指标，这很可能是由于冠层遮光作用的降低导致了蒸发的增加。通常由于冠层和白蚁侵扰，在更深的深度的土壤吸力似乎没有受到明显影响。总而言之，该研究通过显示白蚁侵扰如何严重影响绿色基础设施的性能，为树木的维护问题提供了新的思路。