岷江柏各地理居群生长状况及气候因子分析

岷江柏是我国珍稀濒危保护植物，现主要集中分布在四川西部、甘肃南部的少数几个地区，由于全面调查的缺乏，对其了解和保护很少。样方调查及对岷江柏生长状况的研究表明，马尔康居群岷江柏生长好，群落结构稳定，物种多样性指数高，茂县、小金居群岷江柏生长状况较差，乔木层结构单一，物种多样性指数低。结合气候因子的研究，结果表明岷江柏适于生长在温度适中、雨量充沛、蒸发量小、干燥系数小、太阳辐射较优的环境中。岷江柏分布区的生长状况和气候因子的相关分析表明，总蒸发量、生长季蒸发量和干燥系数是影响岷江柏生长的主要气象因子，年均温、年降雨量对岷江柏地径和高无明显影响，年均温、年降雨量对岷江柏种群乔木层多样性和重要值有重要影响。这说明岷江柏主要生长指标不单单取决于降水的多少，而着重要考虑有多少能够存留在土壤中，也就是说岷江柏分布区的干燥系数大小，能综合反应降水与蒸发的动态关系。

Analysis of growth condition and climate factors in different geographical population of Cupressus chengiana

Cupressus chengiana H., a species on the verge of extinction, is the important protected plant of China. It mainly distributes in several regions of western Sichuan province and southern Gansu province. There was limited understanding and protection of this species due to lack of comprehensive investigation. From plot investigation, the growth condition of Cupressus chengiana was studied in different geographical populations. The results indicated that growth condition of Cupressus chengiana in Barkam (MRK) population was the best, and it had the stable structure of community and high biodiversity. However, growth condition of Cupressus chengiana in Maoxian (MX) and Xiaojin (XJ) populations was worse than that of MRK population, and their structure of arbor layer was singular and biodiversity index was low. Combined with studies of climate factors, Cupressus chengiana was appropriate to grow in environment of temperate temperature, abundant precipitation, little evaporation and aridity, and temperate radiation. From correlation analysis of growth condition of Cupressus chengiana and climate factors, the results indicated that total evaporation, evaporation from may to September and aridity were main factors which affected growth of Cupressus chengiana. Effect of average temperature and precipitation on growth of Cupressus chengiana was not significant, while average temperature and precipitation significantly affected biodiversity and important value of arbor layer. Based on analysis of climate factors, growth of Cupressus chengiana was not lies on a certain single climate index only, aridity, synthetically reacted dynamic relation of precipitation and evaporation, was good index that affected growth of Cupressus chengiana.