Analyzing Climate Suitability of Pinus yunnanensis Based on Kira's Indices

Based on the meteorological data of Yunnan Province and the space distribution data of Pinus yunnanensis,with Kira's indices,and by using statistical methods and GIS software,the spatiotemporal change characteristics of climate resources and the suitable area's changes of P.yunnanensis were analyzed.The results indicated that the mean value of P.Yunnanensis' warmth index was 122.9 ℃·month,ranging from 32.1-204.3 ℃·month,and it's optimum range was 86.1-160.0 ℃·month.The interannual variation curve of Warmth Index(WI) in Yunnan Province was significantly elevated,from 121.30 ℃·month(1970) to 133.57 ℃·month(2002),and the interannual variation curve of Humidity Index(HI) followed a downward trend,from 10.97 mm·(℃·month)-1(1970) to 8.92 mm·(℃·month)-1(2002).The WI fluctuation was more significant than HI fluctuation.The maximum value occurred during 1998(136.63 ℃·month),and the minimum value for the 1976(117.13 ℃·month).However,both the maximum and minimum values belong to the optimal range of P.yunnanensis.Under the condition of climate changing in the future,P.yunnanensis will be centralized in areas of middle Yunnan,but the distribution area will change.The north distributing limitation will not move obviously but the south boundary will atrophy obviously,and the suitable area will decrease stage by stage.