兴安落叶松落叶量和幼苗发生动态的研究

AMOUNT OF FALLING SEED AND SEEDLING OCCURRENCE DYNAMICS IN PRIMITIVE LARIX GMELINI FOREST

采用野外试验的方法,研究了兴安落叶松原始老龄林下兴安落叶松的更新条件。在所研究的四种林型的兴安落叶松原始老龄林之间,更新差别表现在下种、发芽和存活三方面。种子年时,老龄林下种量每平方米达到300-1000粒,各林型落种量从大到小的顺序为:赤杨落叶松林→丛桦落叶松林→草类落叶松林→杜香落叶松林。一年中的幼苗发生过程可分为四个时期,种子萌发主要在6月,幼苗死亡主要在7月,而8月份幼苗种群变化较小。从有利于落叶松种子萌发和幼苗存活的方面来说,各林型的顺序是:丛桦落叶松林>杜香落叶松林>赤杨落叶松林>草类落叶松林。这个顺序主要取决于土壤表层的湿度,即土壤湿度越大,发芽数和存活数越多。

With field experiment method, the regeneration conditions of Larix gmelini in primitive old-growth forest are studied. In mast year, the falling seed in old-growth forest amounts to 300-1000 seeds/m^2, the rank of differentforest types is listed as follows Ass. Alnus mandshurica,L. gmelini>Ass.Betula fruticosa, L.gmelini > Ass. Herbage, L. gmelini>Ass. Ledum palustre,L. gmelini. The emergence of seedling occurs mainly in June,the death predo-minately in July. In August the seeding amount has little change. Theseedling survive shows following sequencs: Ass. Betula fruticosa, L. gmelini>Ass. Ledum palustre, L. gmelini>Ass. Alnus mandshurica, L. gmelini >Ass. Herbage, L. gmelini. This order is mainly determined by soil surefacemoisture. If soil moisture is higher, the seedling of L. gmelini occurs moreabundantly.