Response Of Main Woody Plants' Germination And Leaf Unfolding To Change Of Temperature In The Eastern Monsoonal Region In China

Advances in phenological phases due to climate warming have been widely reported recently. Although there are some improvements in the relevant research in China, some questions are still not answered well, and relatively few phenological studies are about the sensitivity to temperature. Based on the phenological data in the eastern monsoonal resgion in China, this study used statistical and mathematical models to analyse the responses of 35 tree species in Beijing and 4 tree species in the eastern monsoonal resgion to climate warming. The main period that affected the phenophases was identified more accurately and the difference of their sensitivities was analyzed. This study provides scientific evidence for the response of plant phenophase to climate change, plant phenological models and prediction of phenology in the future.The result shows that leaf unfolding dates of 4 tree species became significantly earlier and the interannual variation increased with the latitude in the monsoonal region in China. The relationship between leaf unfolding dates and spring temperature were significant. The periods during February and April were the significant sensitive periods of leaf unfolding dates to temperature in spring. The sensitivities of leaf unfolding dates to temperature in the south area (3.3-9.0d/℃) were higher than that in the north area (1.6-5.6d/℃). Under the effect of spring temperature, the leaf unfolding dates of four tree species were advanced during 1989 and 2006, but the rates of change were not same. The change of temperature in different seasons had diverse effects on plant germination and leaf unfolding. Warmer spring advanced the timing of germination and leafing out, but warmer autumn and winter delayed them. The sensitive periods and sensitivities of bud break and leaf unfolding dates of different species had difference, which is related to the timing of phenophases. The result of simulation in 21th century shows that most of tree species will have significantly earlier germination and leafing out dates, but some other species will have later one. As a result, the responses of plant phenophases in different regions were different, and the variations of phenophases were caused by the responses to the change of temperature of several periods. Different species could show diverse patterns of response to the continued climate change. These differences may be related to the physiological character of different tree species.