Short-term responses of flowering phenology and community structure to nitrogen, phosphorus and potassium in an alpine meadow on the Qinghai-Tibetan Plateau Response of Chestnut Flowering in Beijing to Photosynthetically Active Radiation Variation and Change in Recent Fifty Years Responses of leaf unfolding and flowering to climate change in 12 tropical evergreen broadleaf tree species in Jianfengling, Hainan Island