中文摘要：

为了揭示中国云杉林的地理分布与气候因子间的关系,在中国云杉林15个群系的地理分布范围内选取613个地理坐标点,其中包括云杉各个种分布的海拔上限和下限坐标点各235和228个。通过数字地球系统确定每个点的海拔高程,从中国气象插值数据库获取每个点的气候数据。数据分析分别采用线性回归、变异系数比较和主成分分析（PCA）法。结果显示,中国云杉林分布范围内,年平均气温、最冷月平均气温、最热月平均气温、≥5℃积温、≥0℃积温、年降水量、土壤水分含量和干燥指数α的平均值分别是3.38℃、-9.75℃、14.78℃、1227.83℃.d、2271.19℃.d、712.23mm、80.02%和0.50;各气候因子与中国云杉林垂直分布的上下限间均具有显著的回归关系;除了年平均气温和最冷月平均气温变异系数较大外,其他6个气候因子的变异系数均较小,且彼此间无显著差异;无论是云杉分布的上限还是下限,≥5℃积温和≥0℃积温在PCA第一主分量具有较高的载荷,而年降水量和土壤水分含量在第二、三主分量具有较高的载荷。影响中国云杉林分布的主要气候因子是生长季节积温,其次是年降水量和土壤水分含量。

英文摘要：

Aims Our objective was to examine the relationship between climatic factors and geographical distribution of spruce forests in China.Methods We sampled 613 points within the geographical range of Chinese spruce forests,of which 235 points were at the upper altitudinal limit and 228 at the lower altitudinal limit.The elevation for each point was determined using Google Earth while climatic data were from the Chinese meteorological interpolation database.Linear regression,comparison of coefficient of variation（CV） and principal component analysis（PCA） were conducted for data analysis.Important findings Within the distribution range of Chinese spruce forests,mean values of mean annual air temperature（MAT）,mean air temperature of the coldest month（MTCM）,mean air temperature of the warmest month（MTWM）,growing degree days on a 5 ℃ basis（GDD5） and on a 0 ℃ basis（GDD0）,mean annual precipitation（MAP）,soil moisture（SM） and aridity index（α） are 3.38 ℃,-9.75 ℃,14.78 ℃,1 227.83 ℃.d,2 271.19 ℃.d,712.23 mm,80.02% and 0.50,respectively.Both the upper and lower limits of altitude were significantly correlated with each of the climatic factors.In terms of CV,MAT and MTCM are significantly higher than the other six climatic factors;however,no significant differences were detected among those six.In addition,GDD5 and GDD0 have higher loading on the first principal component,yet MAP and SM have higher loading on the second and third principal component.Major conclusions are that GDD0 and GDD5 are likely the key factors that influence the distribution of Chinese spruce forest,followed by MAP and SM.