Oak species worldwide are experiencing declines, with negative consequences for hardwood forests and their associated biodiversity, but the causes of these declines vary across species and habitats. We examine changes in extent of banj oak-dominated (Quercus leucotrichophora) moist temperate hardwood forests in a Western Himalayan landscape between 1991 and 2017. Using classified satellite imagery from 1991, 2001 and 2017, we found that dense banj oak forests have undergone substantial degradation and loss of area, while chir pine (Pinus roxburghii) forests have expanded, largely by replacing degraded banj oak stands. This transition was most likely to occur at sites that had lower levels of winter precipitation and Topographic Wetness Index (TWI) values and more pine forest in the surrounding landscape. Our findings are consistent with known requirements of shade and moisture for the recruitment of banj oak. Loss of banj oak forests is likely to reduce biodiversity and a number of ecosystem services linked to the well-being of local communities.

世界范围内的橡树树种正在减少，对硬木林及其相关生物多样性产生负面影响，但这些减少的原因因物种和栖息地而异。我们研究了 1991 年至 2017 年期间喜马拉雅西部景观中以班杰橡树为主（Quercus leucotrichophora）潮湿温带硬木森林范围的变化。 使用 1991、2001和 2017 年的分类卫星图像，我们发现茂密的班杰橡树林经历了大幅退化和面积损失，而 chir pine ( Pinus roxburghii) 森林扩大，主要是通过更换退化的班杰橡树林。这种转变最有可能发生在冬季降水量和地形湿度指数 (TWI) 值较低且周围景观中松树林较多的地点。我们的发现与已知的班杰橡树招募所需的遮荫和水分要求一致。班杰橡树林的消失​​可能会减少生物多样性和与当地社区福祉相关的一些生态系统服务。