Incomplete understanding of the processes controlling senescence limits our ability to forecast how the timing of leaf senescence will change in coming decades. In this study, we use a hierarchical Bayesian model (HBM) in association with a 27+ year record of field observations for 12 temperate deciduous tree species collected at Harvard Forest in central Massachusetts to examine how variability in bioclimatic controls affects the timing of leaf senescence. To test how general and extensible our results are over a broader biogeographic range, we used a multi-year record of land surface phenology derived from remote sensing encompassing all forested lands in New England. Results from the HBM showed that while air temperature is an important factor that influences the timing of leaf senescence, photoperiod uniformly exerts the strongest control across all 12 species. Species exhibiting the strongest dependence on photoperiod, particularly Acer species, showed low inter-annual variation and no long-term trends in the timing of leaf senescence. In contrast, species with greater dependence on air temperature, particularly Quercus species, showed statistically significant trends toward later senescence dates in response to long-term warming. Results from analyses conducted at regional scale across all of New England using data derived from remote sensing corroborated results obtained at Harvard Forest. Specifically, relative to ecoregions dominated by Quercus species, the timing of leaf senescence in ecoregions dominated by Acer species exhibited lower interannual variability and lower correlation with year-to-year variation in pre-senescence period mean air temperatures. These results suggest that forecasting how the timing of leaf senescence in temperate forests will change in the future requires species-specific understanding of how bioclimatic forcing controls the timing of leaf senescence.

对控制衰老过程的不完全理解限制了我们预测未来几十年叶片衰老时间将如何变化的能力。在这项研究中，我们使用分层贝叶斯模型 (HBM) 与在马萨诸塞州中部的哈佛森林收集的 12 种温带落叶树种的 27 年以上实地观察记录来研究生物气候控制的变异性如何影响叶片衰老的时间. 为了测试我们的结果在更广泛的生物地理范围内的普遍性和可扩展性，我们使用了来自新英格兰所有林地的遥感的多年地表物候记录。HBM 结果表明，虽然气温是影响叶片衰老时间的重要因素，但 光周期对所有 12 个物种均施加最强的控制。对光周期依赖性最强的物种，尤其是宏碁物种的年际变化较小，叶片衰老时间没有长期趋势。相比之下，对气温有更大依赖性的物种，尤其是栎属物种，在长期变暖的情况下，显示出衰老日期较晚的统计学显着趋势。使用来自遥感数据的数据在整个新英格兰地区进行的分析结果证实了在哈佛森林获得的结果。具体而言，相对于以栎属物种为主的生态区，以宏碁为主的生态区的叶片衰老时间物种表现出较低的年际变化，并且与衰老前平均气温的逐年变化相关性较低。这些结果表明，预测未来温带森林叶片衰老的时间将如何变化，需要对生物气候强迫如何控制叶片衰老时间的物种特异性理解。