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为了在我国北方寒冷半干旱地区大面积营造杨树速生丰产林,从欧洲和美国的高纬度地区引进45个杨树无性系,从国内其它省份引进9个无性系,以北京杨做对照,进行引种选择并比较各无性系的生长量。筛选出国外国内杨树无性系20个,并利用5种聚类方法对各无性系的逐年生长状况进行聚类。划分出:第Ⅰ类有1个无性系,第Ⅱ类包括6个无性系,第Ⅲ类包括12个无性系,第Ⅳ类包括1个无性系。各类无性系胸径5～10a生长量分别为18.4～31.7cm,16.5～21.7cm,14.3～25.0cm,12.8～22.0cm。北京杨作为对照划分在第Ⅲ类。用4种生长方程对各类无性系的胸径及树高生长进行拟合,选Chanter方程描述各类胸径及树高的生长。选育出的无性系都和北京杨一样在当地能良好的生长,有7个无性系生长迅速,是较理想的北方速生杨树无性系,已部分推广,反映良好。
In order to establish poplar fast-growing and high-yield forests in a large area in the cold and semi-arid areas of northern China, 45 poplar clones were introduced from high latitudes in Europe and the United States, 9 clones were introduced from other provinces in China, and Beijing Yang was used as control Introduce selection and compare the growth of clones. 20 poplar clones from abroad were screened, and 5 kinds of clustering methods were used to cluster the annual growth of clones. Divided into: the first class has a clonal, the second class includes six clones, the third class includes 12 clones, the fourth class includes a clonal. The clonal diameter of all clones 5 ~ 10a growth were 18.4 ~ 31.7cm, 16.5 ~ 21.7cm, 14.3 ~ 25.0cm, 12.8 ~ 22.0cm. Beijing Yang as a control in the third category. Four kinds of growth equations were used to fit the DBH and height growth of clones. Chanter equation was chosen to describe the growth of DBH and tree height. The clones bred in the same way as the Beijing poplar grew well in the local area. Seven clones grew rapidly and were the ideal poplar clones in the north, which were partially popularized and reflected well.