Study On Afforestation Types Of Landscape Ecological Forests In Building Demolition Land In Plain Area Of Beijing

Rearch on afforestation mode of building demolition land has important theoretical and practical significance for promoting afforestation project in Beijing plain region.This study based on the building demolition land in Beijing plain region, the soil profile characteristics of new planting area were analysized to comprehensively evaluate the soil quality combined with the original landscape ecological forest.Then sample survey,ecological benefits determination and scenic beauty evaluation were carried out, gray relational analysis method was used to evaluate trees and plant community. Finally technology was carried out on the plant community integration, and puts forward appropriate afforestation mode of building demolition land in the Beijing plain region, and provides the technical support on the afforestation project of building demolition land in Beijing plain region.The main conelusions were as follows:(1) The structures of the original landscape ecological forest were exeessively simple in Beijing plain region, most of which are the models of "tree with herb".The results suggest that the species diversity is low, the average number of species in the tree layer is 1.68, in the shrub layer is 0.92, and in the herb layer is 8.0. DBH of each tree are little different and most of which belong to the single-peak type.(2) The soil quality of the original landscape ecological forest in Beijing plain region is better than the soil quality of new planting area in Beianhe village. Soil quality of different plant communities appears larger space heterogeneity. The SQI values of Ginkgo biloba+Fraxinus chinensis Community、 Acer truncatum Community、 Populus tomentosa+Fraxinus chinensis Community、Juniperus chinensis Community、Eucommia ulmoides Community are above 0.6, while The SQI values of Acer truncatum+Pinus tabulaeformis Community、Eucommia ulmoides+Juniperus chinensis Community、 Eucommia ulmoides+Ginkgo biloba Community、Ailanthus altissima+Fraxinus chinensis Community、Populus tomentosa Community are below 0.3.(3) The original landscape ecological forest have effects on cooling, humidifying, and improving the negative air ion concentration. Populus tomentosa+Fraxinus chinensis Community and Ailanthus altissima Community are performed well on cooling. Ailanthus altissima Community and Juniperus chinensis Community are performed well on humidifying. Ailanthus altissima Community、Robinia pseudoacacia Community、Eucommia ulmoides Community、Populus tomentosa+Fraxinus chinensis Community、Populus tomentosa+Pinus tabulaeformis Community are performed well on improving the negative air ion concentration.(4) The scenic beauty estimation (SBE) values of the original landscape ecological forest of different vegetation types are performed that broad-leaf mixed forest> broad-leaf forest> needle-leaf and broad-leaf mixed forest> needle-leaf forest. Broadleaf trees are conducive to improve the value of landscape.(5) In the evaluation index system of trees, crown, trunk and shape of tree are the most important for the value of landscape quality, while the smell of flowers and the fruit are the least important for the value of landscape quality. the value of landscape quality of trees were evaluated by gray relational analysis method. The result showed that Ginkgo biloba、Populus tomentosa、Robinia pseudoacacia、 Sophora japonica、Populus davidiana、Acer truncatum、Fraxinus chinensis、Pinus bungeana、 Ailanthus altissima are performed well.(6) In the evaluation index system of plant communities,undulate canopy line would inerease the forest SBE vatue. While growth of stand is the least important for the forest SBE vatue. Tthe value of landscape of plant communities were evaluated by gray relational analysis method. The result showed that Populus tomentosa+Fraxinus chinensis Community is the closest to the ideal vegetation community,while Juniperus chinensis Community and Salix matsudana were the worst.The outstanding communities are almost needle-leaf and broad-leaf mixed forest,whlie the poor communities are almost needle-leaf forest and part of needle-leaf forest.