Climatic suitability of the potential geographic distribution of Fagus longipetiolata in China

The potential geographic distribution of Fagus longipetiolata and its climatic controls are studied, based on the maximum entropy (MaxEnt) model and actual geographic distribution data of F. longipetiolata, together with the climatic factors (annual precipitation, annual average daily minimum temperature, annual average daily maximum temperature, and annual solar radiation) reflecting the effects of solar radiation, heat and water resources on plant growth, as well as annual temperature range reflecting seasonal change. The results indicate that the MaxEnt model is suitable for simulating the geographic distribution of F. longipetiolata. The importance of the five factors and their thresholds of climatic adaptability are ranged as annual precipitation (P > 770 mm) > annual average daily minimum temperature (7 degrees C < T-min <20 degrees C) > annual temperature range (DTY <23 degrees C) > annual average daily maximum temperature (16 degrees C < T-max) > annual solar radiation (1.10 x 10(5) W/m(2) < Radi < 1.42 x 10(5) W/m(2)). The general distribution area is controlled by precipitation. Specifically, the western distribution boundary of F. Iongipetiolata (in Gansu, Sichuan and Yunnan provinces) relies on both temperature and solar radiation, and its northern boundary in China (in Shaanxi, Hubei and Hunan provinces) depends on the seasonal change.