Piñon pine-juniper woodlands are strongly influenced by water balance variation imparted by variation in climate, landscape attributes, and tree stand characteristics. To elucidate how these multiple factors shape woodland ecohydrology, we simulated the water balance of woodlands in the Spring (higher precipitation (PPT), higher potential evapotranspiration (PET)) and Sheep (lower PPT, lower PET) mountains of southern Nevada, USA. Simulations included: (1) elevation and climate (2000, 2200 and 2400 m; 3 scenarios); (2) low and moderate adult tree density (2 scenarios); and (3) south-facing, neutral, and north-facing aspects (3 scenarios; 18 scenarios in each mountain range). Due to the interplay between PPT and PET, the lower PPT Sheep mountains were atmospherically less dry (PPT – PET) than the Spring mountains. Following this, the Sheep mountains had higher transpiration partitioning into evapotranspiration (T/ET), whereas transpiration magnitude was higher in the Spring mountains. In both mountain ranges, soil moisture and tree transpiration were highest in winter and spring, and low in summer. T/ET was maximized at 12–15 m${}^2$ ha${}^{-1}$ basal area, illustrating the increasing influence of interception at higher tree densities. Thus, the water balance of these woodlands was driven by PPT, yet partitioning was shaped by PET and tree stand density. Interplay between soil moisture, tree transpiration, evaporation and interception is a defining characteristic of woodlands in southern Nevada, and may be influenced at broader and finer spatial scales. Better understanding of climatic, landscape, and tree stand factors may help to explain high water balance variation observed in woodlands across the western US, and improve understanding of how future change to piñon pine-juniper ecosystems may be realized.

Piñon pine-juniper 林地受到气候、景观属性和林分特征变化所带来的水平衡变化的强烈影响。为了阐明这些多重因素如何塑造林地生态水文，我们模拟了美国内华达州南部春季（降水量较高 (PPT)、潜在蒸散量 (PET) 较高）和绵羊山（PPT 较低、PET 较低）的林地水平衡。模拟包括：（1）海拔和气候（2000、2200 和 2400 m；3 个情景）；(2) 中低成树密度（2 种情景）；(3) 朝南、中立和朝北方面（3 个情景；每个山脉 18 个情景）。由于 PPT 和 PET 之间的相互作用，较低的 PPT 绵羊山脉的大气干燥 (PPT – PET) 比春天山脉低。按照此，绵羊山的蒸腾划分为蒸发蒸腾（T/ET）较高，而春山的蒸腾量级较高。在这两个山脉中，土壤水分和树木蒸腾在冬春季最高，夏季最低。T/ET 在 12–15 m 处最大化${}^2$哈${}^{-1}$基面积，说明在较高的树密度下拦截的影响越来越大。因此，这些林地的水分平衡是由 PPT 驱动的，而分区是由 PET 和林分密度决定的。土壤水分、树木蒸腾、蒸发和截留之间的相互作用是内华达州南部林地的一个决定性特征，可能会在更广泛和更精细的空间尺度上受到影响。更好地了解气候、景观和林分因素可能有助于解释在美国西部林地中观察到的高水平衡变化，并提高对未来如何实现松松-杜松生态系统变化的理解。