日本落叶松结实间隔期现在一般为6—7年,比过去约延长了1倍。间隔期增长的主要原因,是从天然林中采种为主,母树少,而采种量逐渐增加,采种时对母树保护不够,受台风的侵袭使枝条受到损伤等原因造成的。由于结实间隔期延长和母树的减少,种子产量下降,而造林所需要的落叶松种苗又急剧增长,为了解决这一矛盾,除了建立无性系种子园外, Japan larch strong intervals now generally 6-7 years, about twice the extension of the past. The main reason for the increase in the interval is that the seeds are mainly planted from natural forests, with fewer mother trees, while the seed collection rate is gradually increased. As a result, the mother trees are not sufficiently protected when they are planted, and the branches are damaged due to the typhoon attack. Due to the prolongation of the interval between planting and the reduction of the mother tree, the seed yield decreased while the larch seedlings needed for afforestation increased sharply. In order to solve this contradiction, in addition to establishing a clonal seed orchard,