Research Highlights: Forest phenology and productivity were responsive to seasonal heating and chilling accumulation, but responses differed across the temperature range. Background and Objectives: Temperate forests have responded to recent climate change worldwide, but the pattern and magnitude of response have varied, necessitating additional studies at higher spatial and temporal resolutions. We investigated climatic drivers of inter-annual variation in forest phenology and productivity across the Algonquin-to-Adirondacks (A2A) conservation corridor of eastern North America. Methods: We used remotely sensed indices from the AVHRR sensor series and a suite of gridded climate data from the Daymet database spanning from 1989–2014. We used random forest regression to characterize forest–climate relationships between forest growth indices and climatological variables. Results: A large portion of the annual variation in phenology and productivity was explained by climate (_pR² > 80%), with variation largely driven by accumulated heating and chilling degree days. Only very minor relationships with precipitation-related variables were evident. Conclusions: Our results indicate that anthropogenic climate change in the A2A has not yet reached the point of triggering widespread changes in forest phenology and productivity, but the sensitivity of forest growth to inter-annual variation in seasonal temperature accumulation suggests that more temperate forest area will be affected by climate change as warming continues.

中文翻译：

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北美东部阿冈昆至阿地伦达山脉的保护走廊，积聚的热量和寒冷是森林物候和生产力的重要驱动力

研究重点：森林物候和生产力对季节性供暖和寒冷积累有响应，但在整个温度范围内响应都不同。背景与目的：全球温带森林对最近的气候变化做出了响应，但是响应的方式和幅度却有所不同，因此有必要在更高的时空分辨率下进行额外的研究。我们调查了北美东部阿冈昆—阿迪朗达克山脉（A2A）保护走廊的森林物候和生产力年际变化的气候驱动因素。方法：我们使用了来自AVHRR传感器系列的遥感指数以及来自Daymet数据库的一组网格化气候数据，其范围为1989-2014年。我们使用随机森林回归来描述森林生长指数和气候变量之间的森林-气候关系。结果：物候和生产力的年度变化很大一部分是由气候造成的（_p R ² > 80％），而变化主要是由累积的加热和冷却天数引起的。与降水相关的变量只有很小的关系是明显的。结论：我们的结果表明，A2A的人为气候变化尚未达到触发森林物候和生产力发生广泛变化的地步，但森林生长对季节性温度积聚的年际变化的敏感性表明，将有更多的温带森林随着变暖的继续，气候变化会影响气候变化。