Decreased winds and onset of autumnal leaf changes

Analysis of 34 years of climate data reveals that decreased wind speed in the high northern latitudes is associated with delayed onset of annual leaf drop, according to a study. The timing of leaf coloration change and leaf drop, or foliar senescence, vary each autumn, affecting the annual amount of carbon uptake by trees. Chaoyang Wu, Jian Wang, Quansheng Ge, and colleagues report that decreased wind speed in the high northern latitudes is associated with delayed onset of foliar senescence, extending favorable growth conditions later into autumn. The authors compared the timing of foliar senescence with meteorological data, including temperature, precipitation, cloud cover, and wind speed, in northern areas above 50 degrees latitude from 1982 to 2015. In two meteorological datasets, the authors found decreasing wind speed trends at these latitudes. Foliar senescence was measured with 183,448 historical observations at 2,405 sites. For 29.3% of the sites, wind speed was associated with the onset of foliar senescence. A model that accounted for 31% of the foliar senescence timing showed that wind speed was more likely than temperature or precipitation to be correlated with senescence timing. The authors report that the most likely effect of decreased winds is a decrease in soil drying, which can extend the growing season. According to the authors, the multiple effects of wind on plant growth render it as potentially important to carbon uptake and climate feedback as temperature and precipitation.

Article #20-15821: "Widespread decline in winds delayed autumn foliar senescence over high latitudes," by Chaoyang Wu et al.

MEDIA CONTACT: Chaoyang Wu, Chinese Academy of Sciences, Beijing, CHINA; email: wucy@igsnrr.ac.cn

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