Study On Natural Regeneration Of Larix Gmelinii In Cold-temperate Zone

In this paper, the status of natural regeneration in different regeneration location in the original forest, the successive cutting forest and the clear cutting forest , the impact of forest litters on natural regeneration, the seedling structure, the regeneration features and growth dynamics in Larix gmelinii forest in Daxing'anling Mountain area in Inner Mongolia were studied to provided a theoretical basis for scientific forest management.The results were as follows:(1) Under Larix gmelinii leaves canopy, the regeneration seedling both in the original forest and in the successive cutting forest belonged to the stable structures population, and in the clear cutting forest belonged to the declined structure population. The spatial distribution pattern of the natural regeneration seedlings in the three forest types assumes an aggregated distribution. And by the degree of aggregated distribution the highest of the three forest types is the virgin forest, the clear cutting forest comes second, the successtive cutting forest third. Larix gmelinii regeneration seedling had the varying regeneration amounts in the different growing seasons, the most was june.(2) Both in the original forest and in the successtive cutting forest, the tree number of forest gap was higher than leaves canopy,but in the clear cutting forest, the regeneration density of leaves canopy was higher than forest gap. The regeneration density of forest gap and leaves canopy showed significant differences in the three forest types(p<0.05). In the forest gap, The tree number of seedings had a highly significant negative correlation with canopy density, slope and altitude. And the number of seedings had a significant negative correlation with shrub coverage, grass coverage and litter depth(p<0.01).(3) Every forest type, the type of fallen trees showed significant differences, the human disturbed virgin forest, the clear cutting forest and the successtive cutting forest were similar: the number of windfalls were more than dead woods, and the dead woods were more than burned trees; But In the virgin forest, dead trees were significantly more than windfalls and burned trees, and windfalls were more than burned trees. The direction of fallen trees had no significant effect on tree number of regeneration individuals of plant fallen trees, but the decay levels had significant effect on tree number of regeneration individuals of plant fallen trees(p<0.05). The direction of most fallen trees centralized in the southeast. Only the high decay levels includingâ…¢,â…£,â…¤levels, which provided suitable habitats for seedling growth, also the fallen trees of high decay levels had more number of regenation individuals.(4) With the thickening of litter in the virgin forest, the clear cutting forest, the successtive cutting forest and bare land, the tree number of seedings had the trend of decrease. If litter dry weight showed significant differences in the four forest types, the litter dry weight had a negative correlation with the tree number of seedings.