Large-scale planted afforestation worldwide has exacerbated soil desiccation and led to a serious shortage of water resources for forests sustainability in semiarid areas. Consequently, thinning is discussed as an important management approach to conserve water resources and to maintain plantation forestland sustainability. Here, we explored the effects of thinning intensity on semiarid forest production and soil water supply. Three artificial forests of Populus cathayana with an age of 15 yr were selected and thinned with different intensities [1/3 amount of trees removed (T_1/3), 2/3 amount of trees removed (T_2/3), and using no thinning (NT) as a control]. Results showed that thinning presented a significant impact on the above-ground three-dimensional structure of planted forests and increased forest gaps. Meanwhile, the rainfall redistribution pattern changed significantly. Thinning increased throughfall (T_1/3, 43% ± 9%; T_2/3, 79% ± 18%), reduced stemflow (T_1/3, −44 ± 2%; T_2/3, −71% ± 2%), and increased the soil water replenishment (T_1/3, 34% ± 7%; T_2/3, 64% ± 19%) of forest land. Meanwhile, the dead root channel caused by thinning effectively increased the water infiltration rate and groundwater replenishment, and effectively reduced soil water deficit (T_1/3, 41% ± 33%; T_2/3, 57% ± 33%). Through trade-off analysis, we found that non-thinning aboveground biomass yields were the highest, and T_2/3 yields higher water yield, while T_1/3 can maintain acceptable aboveground biomass while keeping better soil water. We conclude that thinning increased soil water supply, reduced soil water deficit and maintained forestland sustainability, and there are synergies of thinning on forest production and soil water supply through rainfall redistribution for maintaining the sustainability of semiarid plantation forestlands.

中文翻译：

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间伐对森林生产和降雨再分配的影响：减少土壤水分亏缺并提高半干旱人工林地的可持续性

世界范围内大规模的植树造林加剧了土壤干燥，导致半干旱地区森林可持续发展的水资源严重短缺。因此，间伐被认为是保护水资源和维持人工林可持续发展的重要管理方法。在这里，我们探讨了间伐强度对半干旱森林生产和土壤水分供应的影响。选择了3个15年生杨树人工林，进行不同强度间伐[1/3砍伐树木（T _1/3），2/3砍伐树木（T _2/3)，并使用不细化 (NT) 作为对照]。结果表明，间伐对人工林地上三维结构的影响显着，林隙增大。同时，降雨再分配格局发生明显变化。间伐量增加 (T _1/3 , 43% ± 9%; T _2/3 , 79% ± 18%)，减少茎流 (T _1/3, -44 ± 2%; T _2/3 , -71% ± 2%），增加林地土壤补水量（T _1/3 , 34% ± 7%; T _{2/3 , 64% ± 19%）。}同时，间伐造成的死根通道有效提高了水分入渗率和地下水补给量，有效减少了土壤水分亏缺（T _1/3, 41% ± 33%; T _2/3, 57% ± 33%)。通过权衡分析，我们发现非间苗的地上生物量产量最高，T _2/3产生更高的产水量，而T _1/3可以在保持较好的土壤水分的同时保持可接受的地上生物量。我们得出结论，间伐增加了土壤水分供应，减少了土壤水分亏缺并保持了林地的可持续性，并且间伐通过降雨重新分配对森林生产和土壤水分供应具有协同作用，以维持半干旱人工林林地的可持续性。