1.College of Soil and Water Conservation in Beijing Forestry University,Key Lab of Soil and Water Conservation and Combating Desertification,Ministry of Education,100083,Beijing;2.Sci-Tech College of Shandong Agriculture University 271000,Tai'an,Shandong: China
Abstract：Tilia tomentosa Moench originated from Europe and introduced successfully to America,is a kind of superior plant resources for its ecological,economic and societal values.In order to successful introduction of Silver linden,the regions for introduction of silver linden in Northern China are divided and main climatic factors affecting growth of silver linden in 30 sample plots of Northern China and 18 distribution region of America are analyzed by applying PCA and cluster analysis statistic methods.The results show that temperature,heat,precipitation and its distribution are the critical climate factors to determine the introduction and cultivation of silver linden.Climatic factor indexes suitable to grow of silver linden are annual mean temperature(3-18℃),≥10℃ accumulated temperature(2300-6000℃),Mean temperature in coldest month(-14-6℃),Kira's warmth index(51-152),Kira's coldness index(<-68),precipitation during the growing period(200-850mm),Kira's aridity index for growing period(1.5-7.4) and annual duration of sunshine(2300-3700h).Comparing with the distribution regions of silver linden,the lower temperature in winter,inadequate precipitation during the growing period and the difference in rain tape are common problems for Northern China to introduce silver linden.There are three climate types suitable for growth of silver linden in Northern China,namely,warm temperature semi-humid climate region at first,moderate temperature semi-humid/arid and semi-humid climate region at second.
2006, Vol. 4 
