Warming does not delay the start of autumnal leaf coloration but slows its progress rate

Abstract

Aim: Initiation of autumnal leaf senescence is crucial for plant overwintering and ecosystem dynamics. Previous studies have focused on the advanced stages of autumnal leaf senescence and reported that climatic warming delayed senescence, despite the fundamental differences among the stages of senescence. However, the timing of onset of leaf coloration (DLCO), the earliest visual sign of senescence, has rarely been studied. Here, we assessed the response of DLCO to temperature. Location: 30–75° N in the Northern Hemisphere. Time period: 2000–2018. Major taxa studied: Deciduous vegetation. Methods: We retrieved DLCO from high-temporal-resolution satellite data, which were then validated by PhenoCam observations. We investigated the temporal changes in DLCO and the relationship between DLCO and temperature by using satellite and ground observations. Results: DLCO was not significantly (p >.05) delayed between 2000 and 2018 in 94% of the area. DLCO was positively (p