Characterization of Retention of Atmospheric Particles by Five Typical Scenic Recreational Forests in Beijing
[Objective]This study aimed to characterize the retention of atmospheric particles by different tree species at both the leaf and canopy scales by the analysis of the variation in the retention of atmospheric particles by individual leaves and forest canopies of different tree species under the same pollution background,therefore to provide a theoretical basis for creating urban forests that can efficiently retain atmospheric particles.[Method]A survey was carried out on representative scenic recreational forests in plain areas around Beijing's Fifth Ring Road,five typical scenic recreational forests in the Olympic Park(Pinus armandii-Ginkgo biloba mixed forests,Populus tomentosa-Fraxinus chinensis mixed forests,Salix matsudana pure forest,Populus tomentosa pure forest,and multi-species and multi-layer conifer-broadleaf mixed forest)were selected for the study.The elution-weighing-particle size-analysis method was used to measure the amount of atmospheric particles retained per unit leaf area of each tree species.The leaf area index was used to calculate the amount of particles retained by different tree species per hectare for different particle size categories.Based on the canopy area ratio of individual species to the entire forest,the retention amount of different particle size categories per unit area of pure forest or mixed forest was calculated.[Result]There are significant differences in the particle size distribution of atmospheric particles retained by the leaves of different tree species among different forest types.The retention amount of particles per unit leaf area varies among tree species with particle size categories and forest types.At the leaf scale,the comprehensive ranking of the ability to retain atmospheric particles with different particle size categories is:Ginkgo biloba＞Juniperus chinensis＞Acer truncatum＞Koelreuteria paniculata＞Pinus armandi＞Platycladus orientalis＞Fraxinus chinensis＞Salix matsudana＞Populus tomentosa.The ability of different forest canopies to retain atmospheric particles differs significantly,up to a 20-fold difference.The ranking of the amount of atmospheric particles retained per unit area of different forest types does not change with particle size categories.For all particle size categories,the retention amount is the highest in the Pinus armandi-Ginkgo biloba mixed forest,followed by multi-tree conifer-broadleaf mixed forest,Salix matsudana pure forest,Populus tomentosa-Fraxinus chinensis mixed forest,and Populus tomentosa pure forest.[Conclusion]Among the nine tree species studied,Ginkgo biloba,Juniperus chinensis,and Acer truncatum are high dust-retention species;Koelreuteria paniculata,Pinus armandii,and Platycladus orientalis are medium dust-retention species;Fraxinus chinensis,Salix matsudana,and Populus tomentosa are low dust-retention species.Additionally,the study identifies forest structure characteristics that can efficiently retain atmospheric particulate matter:multiple high dust-retention species+multilayered canopy+staggered tree density.To maximize the dust retention effectiveness of urban forests,attention should be paid to both the selection of high dust-retention tree species and the reasonable design of forest structure.
atmospheric particulate matterdust retentionPM2 5air pollutionforest stand
万方数据
维普
