Spring phenology is essential in modeling the carbon balance of high‑latitude ecosystems and is possibly sensitive to climate change. In the present study, we evaluated the onset of the growing season for three species (paper birch, bog blueberry, and bog Labrador tea) in interior Alaska from 2012 to 2019 using photos taken using time‑lapse cameras. We also evaluated the onset of the growing season at the ecosystem scale from 2010 to 2019 on the basis of the CO₂ flux by the eddy covariance method at the site. On the basis of the growing degree‑day (GDD) model with the parameters estimated using the Bayesian approach, we found that the interannual variations in the spring onsets were explained by the model, and the thermal forcing requirement differed among the species. At the ecosystem scale, the spring onset was closely linked to the snow disappearance date. Under the possible future climate scenarios indicated by the representative concentration pathway 8.5 scenario, the spring onsets were predicted to be one to three weeks earlier than the present dates for the three species. The ecosystem‑scale onsets were also predicted to be five days to a little over a month earlier at the end of this century. The future spring onset is highly sensitive to the snow disappearance date for high‑latitude vegetation; thus, further understanding of climate change before snowmelting is required.

中文翻译：

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基于延时相机和涡流协方差测量确定的阿拉斯加内陆年轻森林的春季发作

春季物候学对于模拟高纬度生态系统的碳平衡至关重要，并且可能对气候变化很敏感。在本研究中，我们使用延时相机拍摄的照片评估了 2012 年至 2019 年阿拉斯加内陆三个物种（纸桦树、沼泽蓝莓和沼泽拉布拉多茶）的生长季节的开始。我们还基于 CO ₂评估了 2010 年至 2019 年生态系统尺度上生长季节的开始。现场涡流协方差法。基于使用贝叶斯方法估计参数的生长度日（GDD）模型，我们发现该模型解释了春季开始的年际变化，并且物种之间的热强迫要求不同。在生态系统尺度上，春季开始与积雪消失日期密切相关。在代表性浓度路径 8.5 情景指示的未来可能的气候情景下，预计这三个物种的春季开始时间比当前日期提前一到三周。预计在本世纪末，生态系统规模的开始时间也将提前五天到一个多月。未来春季来临对高纬度植被的积雪消失日期高度敏感；