Increased water yield and baseflow and decreased peak flow are common goals of watershed service programs. However, is the forest management often used in such programs likely to provide these beneficial watershed services? Many watershed service investments such as water funds typically change less than 10% of watershed land cover. We simulate the effects of 10% forest-cover change on water yield, low flow, and high flow in hydrologic models of 29 watersheds around the world. The forest-cover changes considered are: forest restoration from degraded natural lands or agriculture, forest conversion to agriculture, and forest conversion to urban cover. We do not consider grassland restoration by removal of alien tree species from riparian zones, which does increase water yield and low flow. Forest restoration from locally-predominant agricultural land resulted in median loss in annual water yield of 1.4%. Forest restoration reduced low flow and high flow by ∼3%. After forest restoration, low flow increased in ∼25% of cases while high flow and water yield declined in nearly all cases. Development of forest to agriculture or urban cover resulted in a 1–2% median increase in water yield, a 0.25–1% increase in low flow, and a 5–7% increase in high flow. We show that hydrologic responses to forest cover changes are not linearly related to climate, physiography, initial land cover, nor a multitude of watershed characteristics in most cases. These results suggest that enhanced streamflow watershed services anticipated from forest restoration or conservation of 10% or less of a watershed are generally modest.

分水岭服务计划的共同目标是增加水的产量和基础流量，减少峰值流量。但是，此类计划中经常使用的森林管理是否有可能提供这些有益的分水岭服务？许多流域服务投资，例如水基金，通常只改变不到10％的流域土地覆盖率。我们在全球29个流域的水文模型中模拟了10％的森林覆盖率变化对水产量，低流量和高流量的影响。所考虑的森林覆盖率变化包括：从退化的自然土地或农业中恢复森林，将森林转变为农业，以及将森林转变为城市覆盖。我们不考虑通过从河岸地区清除外来树种来恢复草地，这确实增加了水的产量和流量。从当地占主导地位的农业用地恢复森林后，年水产量的中位数损失为1.4％。森林恢复使低流量和高流量减少了约3％。森林恢复后，低流量在约25％的情况下增加，而高流量和水的产量在几乎所有情况下都下降。从森林到农业或城市覆盖的发展导致水产量中位数增加1-2％，低流量增加0.25-1％，高流量增加5-7％。我们表明，在大多数情况下，对森林覆盖率变化的水文响应与气候，地貌，初始土地覆盖率或多种流域特征均不具有线性关系。这些结果表明，从森林恢复或流域的10％或更少的保护中获得的期望的径流集水区服务通常是适度的。