State Key Laboratory of Tibetan Plateau Earth System, Resources and Environment (TPESRE), Institute of Tibetan Plateau Research, Chinese Academy of Sciences, Beijing, China.
School of Natural Resources and the Environment, University of Arizona, Tucson, AZ, USA.
Nat Ecol Evol. 2022 Apr;6(4):397-404. doi: 10.1038/s41559-022-01668-4. Epub 2022 Feb 28.
Climatic warming alters the onset, duration and cessation of the vegetative season. While previous studies have shown a tight link between thermal conditions and leaf phenology, less is known about the impacts of phenological changes on tree growth. Here, we assessed the relationships between the start of the thermal growing season and tree growth across the extratropical Northern Hemisphere using 3,451 tree-ring chronologies and daily climatic data for 1948-2014. An earlier start of the thermal growing season promoted growth in regions with high ratios of precipitation to temperature but limited growth in cold-dry regions. Path analyses indicated that an earlier start of the thermal growing season enhanced growth primarily by alleviating thermal limitations on wood formation in boreal forests and by lengthening the period of growth in temperate and Mediterranean forests. Semi-arid and dry subalpine forests, however, did not benefit from an earlier onset of growth and a longer growing season, presumably due to associated water loss and/or more frequent early spring frosts. These emergent patterns of how climatic impacts on wood phenology affect tree growth at regional to hemispheric scales hint at how future phenological changes may affect the carbon sequestration capacity of extratropical forest ecosystems.
气候变暖改变了植被季节的开始、持续和结束时间。虽然之前的研究表明热条件与叶物候之间存在紧密联系，但对于物候变化对树木生长的影响知之甚少。在这里，我们利用 1948-2014 年的 3451 个树木年轮年表和每日气候数据，评估了在北温带外地区热生长季节开始与树木生长之间的关系。热生长季节的提前开始促进了降水与温度比高的地区的生长，但限制了寒冷干燥地区的生长。路径分析表明，热生长季节的提前开始主要通过缓解北方森林木质形成中的热限制以及延长温带和地中海森林的生长期来促进生长。然而，半干旱和干燥的亚高山森林并没有从生长的提前开始和更长的生长季节中受益，这可能是由于相关的水分流失和/或更频繁的早春霜。这些关于气候对木质物候影响如何影响区域到半球尺度树木生长的新兴模式表明，未来的物候变化可能如何影响北温带森林生态系统的碳固存能力。
