银叶椴在我国北方适宜引种区域的探讨

 为使银叶椴引种驯化成功,对我国北方30个样点及美国18个银叶椴分布区的10项气候要素进行主成分分析和模糊聚类,划分我国北方地区银叶椴适宜引种的区域,分析影响我国引种银叶椴的主要气候因素。结果表明:温度、热量、降水及其雨型是决定银叶椴引种栽培的主要气候因素。适于银叶椴生长的气候因子指标为:年平均气温（3～18℃）、≥10℃积温（2300～6000℃）、最冷月均温（-14～-6℃）、温暖指数（51～152）、寒冷指数（<-68）、生长期降水量（200～850mm）、生长期干燥度指数（1.5～7.4）、年日照时间（2 300～3700h）。与美国银叶椴分布区相比,冬季低温、生长季节降水不足、雨型不同是我国北方引种银叶椴所面临的普遍问题。适宜银叶椴在我国生长的气候类型为暖温带半湿润气候区;较适宜生长的气候类型区有温带半湿润半干旱气候区和温带湿润半湿润气候区2类。

Regional approach for introduction of Tilia tomentose in northern China

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.