Plant phenological processes significantly impact ecosystem function and services across multiple ecological scales and are widely viewed to be among the most sensitive indicators of global environmental change. Remote sensing has crucially expanded our understanding of phenological variability. Yet, we continue to lack a complete mechanistic understanding of phenology and its variability and drivers, which is important to the development of predictive models, especially under continued environmental change. We combined field inventories and Land Surface Phenology (LSP) approaches, using 36 years of Landsat phenological observations, to characterize the degree to which long-term spring greenup patterns are shaped by topography, vegetation, and topographically structured vegetation assembly processes within a dissected forest landscape in southeastern Ohio. We found temporal and spatial variability among the field samples where greenup patterns displayed rapid change (18 total days) over relatively short distances (<1 km). Slope position explained the most variation (35%), where the bases of hills displayed the latest timing in spring greenup. However, we found that differences in terrain aspect and slope influenced canopy diversity, height, and composition of forest stands, influencing plant community processes that support heterogeneity in spring leaf-out timing. Understanding how forest phenology is shaped by direct and often complex interacting processes that influence the distribution of species assemblages supports new insight into phenological variability and, importantly, the management of forest ecosystems facing continued environmental change.

植物物候过程在多个生态尺度上显着影响生态系统功能和服务，被广泛认为是全球环境变化最敏感的指标之一。遥感技术极大地扩展了我们对物候变异的理解。然而，我们仍然缺乏对物候学及其变异性和驱动因素的完整机械理解，这对于预测模型的开发很重要，尤其是在持续的环境变化下。我们结合实地清查和地表物候 (LSP) 方法，使用 36 年的 Landsat 物候观测，来表征地形、植被、俄亥俄州东南部解剖森林景观中的地形结构植被组装过程。我们发现田间样本的时间和空间变化，其中绿化模式在相对较短的距离（<1 公里）内显示出快速变化（总共 18 天）。坡度位置解释了最大的变化 (35%)，其中山丘的底部显示了春季绿化的最新时间。然而，我们发现地形方面和坡度的差异影响了林分的冠层多样性、高度和组成，影响了支持春季脱叶时间异质性的植物群落过程。了解影响物种组合分布的直接且通常复杂的相互作用过程如何塑造森林物候学，支持对物候变异性的新见解，重要的是，