We applied an eco‐hydrologic model (Regional Hydro‐Ecologic Simulation System [RHESSys]), constrained with spatially distributed field measurements, to assess the impacts of forest‐fuel treatments and wildfire on hydrologic fluxes in two Sierra Nevada firesheds. Strategically placed fuels treatments were implemented during 2011–2012 in the upper American River in the central Sierra Nevada (43 km²) and in the upper Fresno River in the southern Sierra Nevada (24 km²). This study used the measured vegetation changes from mechanical treatments and modelled vegetation change from wildfire to determine impacts on the water balance. The well‐constrained headwater model was transferred to larger catchments based on geologic and hydrologic similarities. Fuels treatments covered 18% of the American and 29% of the Lewis catchment. Averaged over the entire catchment, treatments in the wetter central Sierra Nevada resulted in a relatively light vegetation decrease (8%), leading to a 12% runoff increase, averaged over wet and dry years. Wildfire with and without forest treatments reduced vegetation by 38% and 50% and increased runoff by 55% and 67%, respectively. Treatments in the drier southern Sierra Nevada also reduced the spatially averaged vegetation by 8%, but the runoff response was limited to an increase of less than 3% compared with no treatment. Wildfire following treatments reduced vegetation by 40%, increasing runoff by 13%. Changes to catchment‐scale water‐balance simulations were more sensitive to canopy cover than to leaf area index, indicating that the pattern as well as amount of vegetation treatment is important to hydrologic response.

中文翻译：

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内华达山脉混合针叶林的燃料处理和野火对径流的影响

我们应用了生态水文模型（区域水文生态模拟系统[RHESSys]），并在空间分布的现场测量结果的约束下，评估了内华达山脉两个喷火场中森林燃料处理和野火对水文通量的影响。在2011-2012年期间，在内华达山脉中部（43 km ²）的美洲河上游和内华达山脉南部（24 km ²）的弗雷斯诺河上游实施了具有战略意义的燃料处理）。这项研究使用了机械处理中测得的植被变化和野火中建模的植被变化来确定对水平衡的影响。受约束的源头模型已根据地质和水文的相似性转移到较大的流域。燃料处理覆盖了18％的美国人和29％的Lewis流域。在整个流域平均水平，在内华达山脉中部湿润的处理导致植被减少相对较小（8％），导致干湿年平均增加12％的径流量。进行和不进行森林处理的野火分别使植被减少了38％和50％，径流增加了55％和67％。内华达山脉南部较干燥的处理也使空间平均植被减少了8％，但与未进行处理相比，径流响应仅限于增加不到3％。处理后的野火使植被减少了40％，径流增加了13％。集水规模水平衡模拟的变化对冠层覆盖比对叶面积指数更敏感，这表明模式和植被处理量对水文响应很重要。