It is not well understood if wildfires induce soil water repellency in broadleaf deciduous forests, such as those endemic to the Blue Ridge Mountains of the eastern United States. In 2016, widespread wildfires provided an opportunity to study soil water repellency in this region. We selected sites in four locations with low to moderate burn severities, along with unburned controls. We estimated soil water repellency using water drop penetration time measurements from the surface (i.e. ash or organic) layer to ~5 cm within the underlying mineral layer. Two months after the fires, water repellency was detected in all locations and was greater in more severely burned sites. One location had the greatest water repellency in surface ash (frequency of occurrence: 68–74%), whereas the other locations showed greatest repellency at the ash–mineral interface (40–96%). Unburned soils rarely showed repellency (0–18%). Burned soils also exhibited water repellency 1 year post fire. The study results suggest that combustion of non-resinous foliage within litter layers can cause water repellency in deciduous forests, meaning that this condition is not exclusive to coniferous and dryland forests. The duration of impact depends on fire severity, and may enhance overland flow and sediment transport in affected landscapes.

中文翻译：

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美国蓝岭山脉野火后的土壤防水性

目前尚不清楚野火是否会导致阔叶落叶林（例如美国东部蓝岭山脉特有的落叶林）的土壤拒水。2016 年，广泛的野火为研究该地区的土壤防水性提供了机会。我们在四个地方选择了低到中等烧伤严重程度的地点，以及未烧毁的对照。我们使用从表面（即灰分或有机）层到下层矿物层内约 5 厘米的水滴渗透时间测量值来估计土壤拒水性。火灾发生两个月后，所有地点都检测到防水性，并且在烧得更严重的地点防水性更强。一个地点的表面灰分拒水性最大（发生频率：68-74%），而其他位置在灰分-矿物界面显示出最大的排斥性（40-96%）。未燃烧的土壤很少表现出排斥性（0-18%）。燃烧后的土壤在火灾后 1 年也表现出防水性。研究结果表明，枯枝落叶层内非树脂树叶的燃烧会导致落叶林的防水性，这意味着这种情况不仅仅发生在针叶林和旱地森林中。影响的持续时间取决于火灾的严重程度，并且可能会增强受影响景观中的地表水流和沉积物输送。这意味着这种情况不仅限于针叶林和旱地森林。影响的持续时间取决于火灾的严重程度，并且可能会增强受影响景观中的地表水流和沉积物输送。这意味着这种情况不仅限于针叶林和旱地森林。影响的持续时间取决于火灾的严重程度，并且可能会增强受影响景观中的地表水流和沉积物输送。