Forest age structures have been reported to be substantially influenced by natural and anthropogenic disturbances worldwide. However, related biophysical feedback to climate is not well understood. This study aims to investigate the biophysical impact of changes in forest age on surface temperature and illustrate the mechanisms underlying such temperature differences. To this end, we use data from five paired evergreen needleleaf forest (ENF) eddy covariance towers in North America. Results show that older ENF is 1.7 K cooler than younger ENF at annual scale. The latent and sensible heat fluxes of older forests dominate an average cooling effect of −1.9 K, which counteracts albedo-driven warming (+2.3 K). Additional warming effect is further offset by emissivity (−1.1 K) and incoming radiation (−0.5 K). Our results confirm that considering forest age may facilitate improved forest management to local climate mitigation and adaptation in future climate change.

据报道，森林年龄结构受到全世界自然和人为干扰的很大影响。但是，对气候的相关生物物理反馈知之甚少。这项研究旨在调查森林年龄变化对地表温度的生物物理影响，并阐明这种温度差异的潜在机制。为此，我们使用了来自北美的五个成对的常绿针叶林（ENF）涡流协方差塔的数据。结果表明，在年尺度上，较旧的ENF比较年轻的ENF低1.7K。较老森林的潜热通量和显热通量主导着-1.9 K的平均降温效果，这抵消了反照率驱动的变暖（+2.3 K）。额外的变暖效应被发射率（-1.1 K）和入射辐射（-0.5 K）进一步抵消。