Studies On The Community Character And It's Interaction With Environment Factors Of Aerial Seeding Pinus Tabulaeformis Stands

The flora composition, floristic elements, community appearance and community structure of Aerial Seeding Pinus tabulaeformis communities were studied in Qingquanbao and Baimujing Aerial Seeding areas in Yanqing Country of Beijing.Research on the 40 factors of undergrowth, soil and environment was carried on in Aerial Seeding Pinus tabulaeformis stands of 10a, 17a and 25a, the site of north and north-west faced and five forest types of Aerial seeding Pinus tabulaeformis, Quercus mongolica, Quercus mongolica-aerial Pinus tabulaeformis, Populus davidiana and Pinus tabulaeformis plantations. The research of environment conditions was also carried on in Aerial Seeding Pinus tabulaeformis stands in different densities. The main results are as follows:1, The spatial distribution of aerial seeding Pinus tabulaeformis communities showed block distribution horizontally and with obvious vertical layers. Because the Quercus are more competitive than Pinus tabulaeformis, and it is difficult for Pinus tabulaeformis to regeneration in the high density situation, the Pinus tabulaeformis communities are tend to be replaced by Quercus or some other broad-leaf species. Perhaps the aerial seeding Pinus tabulaeformis communities are not relatively steady.2, In aerial seeding Pinus tabulaeformis communities, Genus take uniform distribution and dominant genera seemed relatively invisible. Temperate types took 55 genera, which accounted for 80.88% of the total genus number.3, Evaluation System of undergrowth-soil property-forestry environment in aerial seeding Pinus tabulaeformis stands of different ages (10a, 17a and 25a) and different site types were established based on quantitative study. Through correlation analysis, it is indicated that the undergrowth, soil properties and forestry environments comprise a whole system affected by each other. Based on quantitative study on the environment factors, the environment heterogeneity theory, and the energy theory, explanations about the disparities of Species diversities among Aerial Seeding Pinus tabulaeformis communities of different ages and site types were given.4, Based on the quantitative study of undergrowth, soil and environment qualities in aerial seeding Pinus tabulaeformis stands of different ages, it is suggested that the thinning should be carried out in aerial seeding Pinus tabulaeformis between ages of 10 and 17.5, Based on the quantitative study of undergrowth, soil and environment qualities in aerial seeding Pinus tabulaeformis stands of different site types, it is suggested that the thinning intensity in north faced site should be heavier than those in north-west faced site.6, It is pointed out that the humidity vertical variation coefficient, humidity daily variation coefficient, average light intensity, average humidity could be regarded as indicators to assess environment quality. The thinning would improve the environment quality in aerial seeding Pinus tabulaeformis. As planting density decreased, Component score of the enviroment factors increased gradually: 1830 N/hm2(0.807)>4100N/hm2(-0.119)>8000N/hm2(-0.689).7, Evaluation System of undergrowth-soil property-forestry environment qualities in various forest communities were applied based on quantitative research. It indicate that the score of undergrowth-soil-environment quality of aerial seeding Pinus tabulaeformis (-0.779) are obviously less than that of other forest types. While the scores of the Populus davidiana forests and Pinus tabulaeformis plantations are 0.553 and 0.454.