Regional and Species Variations in Spring and Autumn Phenology of 25 Temperate Species in South Korea

摘要

Phenological shifts associated with climate and environmental change are evident in temperate forests. Further dense and comprehensive observations are necessary to understand the species-specific and regional variation in the responses of plant phenology to climate change. This study first introduces the national-scale phenology network (NPN) over South Korea. By having newly established phenology datasets for the period 2009-2018, we analyze spatial and temporal variations of phenology of 21 deciduous species in spring and autumn as well as 4 evergreen species in spring. For deciduous species, the phenological responses are examined using the dates of budburst, leaf unfolding, leaf coloring, and leaf fall, whereas the times of pollen start and pollen peak are adopted to investigate the responses of evergreen species. The average dates of budburst and leaf unfolding are changed by -1.1 and - 1.3 day/year, respectively, in agreement with the observed trends in temperature. The pollen activity (start and peak) of evergreen species is significantly advanced by 1.4 day/year throughout Korea, suggesting apparent phenological response of evergreen species to the warming. Especially, the shrub had up to 45 larger temperature sensitivity than the subtree or tree in spring. By contrast, changes in the autumn phenology of deciduous species are not evident because of the large interannual variability in the dates of leaf coloring and leaf fall. Then, the large interannual variation in autumn phenology could constrain the interannual variability in the length of the growing season of temperate forest. We further expect on-going efforts on national-scale phenology monitoring will have an important contribution to understanding vegetation growing season changes related to warming.