大兴安岭北部原始老龄林内兴安落叶松幼苗种群的生命统计研究

天然落叶松老龄林每１个种子年后第２年，林地表面即会出现大量天然幼苗１００－２７０株·ｍ－２．幼苗发生时间集中，绝大多数在６月底．赤杨落叶松林幼苗发生较丛桦落叶松林和杜香落叶松林的迟．幼苗死亡时期也集中，主要在幼苗发生后的１５天内．其间杜香落叶松林的幼苗死亡率为４８％，３年内９７％；丛桦落叶松林为２９％和６６％；赤杨落叶松林为３３％和６９％．７月以后发生的幼苗存活率很低，早期发生的幼苗占优势，死亡率低．丛桦落叶松林和杜香落叶松林幼苗的早期优势显著，尤其是杜香落叶松林．幼苗存活的年际变化很大，落叶松幼苗数量丛桦落叶松林＞赤杨落叶松林＞杜香落叶松林．

Demography of Larix gmclini seedling population in natural old-growth forests of north Daxinganling Mts.

Demography of Larix gmelini seedling population in natural old-growth forest of northDaxinganling Mts. show that after each fructification year, a great number of larchseedlings are emerged mainly in next June, and part of them died within a period of 15days after emergence. The emergence of L. gmelini seedlings in old-growth L. gmeliniAlnus mandshurica forest is later than in L. gmelini-Betula fruticosa and L. gmeliniLedum palustre forests. The seedlings have a mortality of 48% within 15 days and of97% in 3 years for L. gmelini-L. palustre forest, 29% and 66% for L. gmelini-B. fruticosa forest, and 33% and 69% for L. gmelini-A. mandshurica forest. The seedlings emerged after July have a low survival rate, and appear a prominent advantage of early establishment in L. gmelini-B. fruticosa and L. gmelini-A.mandshurica forests, especially inthe latter. The annual survival rate of seedlings of different forests varies greatly, and decreases in order of L. gmelini-B. fruticosa, L. gmelini-A. mandshurica and L. gmelini-L.palustre.