日本落叶松是我省引种用于大面积造林的主要用材树种之一。为了迅速提供良种,我们从1973年起,营建了日本落叶松嫁接种子园,其中80%的母树出现不同程度的歪干偏冠现象。为了促使母树正常生长发育,达到结实早、稳产高产的目的,对母树进行整形修剪试验,现已初见成效。一、纠正歪干偏冠1. 歪干偏冠初步认为有两个原因:一是与母树接穗的遗传性有关。例如在1975年定植 Japanese larch is introduced in our province for large-scale afforestation one of the main timber species. In order to provide good seed quickly, we started to construct the Japanese larch grafted seed orchard in 1973, in which 80% of the mother trees appear crooked and crowned crowns to some extent. In order to promote the normal growth and development of the mother tree, to achieve the purpose of early, stable and high yielding mother tree truncation test, has achieved initial success. First, to correct crooked crown 1. Crooked crown partial tentatively believe there are two reasons: First, the genetic relationship with the mother tree scion. For example colonized in 1975