Effects Of Light Environment On Competition Of Regeneration Population In Abies Holophylla Broad-leaved Forest In Changbai Mountain

Abies is Pinaceae Abies genus of evergreen coniferous tree species, is the spice industry, light chemical industry and food processing industry’s best raw materials, and is also one of the best species of the shelterbelt. In China, Abies mainly distributed in the Changbai Mountain area, and is the main associated species in the forest. Due to human reason, the Abies update poor in community regeneration layer. However, in the appropriate environmental conditions and less human disturbance environment, Abies is likely to dominate in the updated community. In this paper, Abies is as the research object. This paper, on the basis of previous research methods, use Hegyi single tree competition index model and intraspecific and interspecific competition theory, mainly through field survey and Abies saplings root partition mining methods to analyze Abies and other plant populations competition interaction under the different light environments, to study the root distribution pattern of Abies response to competition, as well as of the competitive relationship between Abies ground part and underground part, to explore the competition mechanisms impacting Abies update sapling growth in the natural environment, to lay the foundation for the rational management of natural secondary forest of Abies.The results show that:(1) The Abies update saplings average age of8years, the maximum height of0.87m, the maximum biomass (dry weight)237.31g, coverage of30%, abundance of23.7%;(2) Abies sapling height, ground diameter, leaf biomass, stem biomass, root biomass and total biomass of each other were tested positive relationship and significant correlation (P<0.01);(3) Plant competition intensity with the increase of distance reduced (P<0.05),0-20cm is the most competitive range,0-60cm is the main area affected by competition, the strength of interspecific competition than intraspecific competition;(4) The Pearson correlation test results show that the light intensity and intraspecific competition index (CIh) are negatively correlated, and the degree of difference is significant (P<0.01) and no significant correlation between other competition intensity index and light environment;(5) the natural environment, the different levels of distance, a different vertical distance, the degree of difference of Abies root length density, root surface area was significantly (P=0.005, P=0.002), but the biomass density was no significant difference; The Abies update saplings root growth pattern give priority to shallow-rooted and transverse stretching to get moisture and nutrients;(6) Within the0-20cm level hierarchical, diameter greater than2mm of the root system more, and neighborhood plant density and root specific root length, specific surface area and competition wood density (plants/m2) showed a significant positive correlation (P=0.002,P=0.003); density of the neighborhood plant doesn’t impact the vertical stratification of Abies roots;(7) The roots of more than2mm in diameter than the0-2mm of the root system is more conducive to absorption of soil nutrients and moisture, and greater support photosynthesis, providing more carbohydrate synthesis and distribution for Abies growth.