Objective To study the dust-retention ability, dynamic change and spatial distribution characteristics among three road protection forests.

Method Three types of road protection forests (Pinus tabulaeformis forest, Sabina chinensis forest and Ginkgo biloba forest) were observed continuously in spring at different distances from the road, and the dust retention ability of the road protection forests was compared. Rainfall, wind speed and relative humidity, PM₁₀ and other factors influencing the dynamics and spatial distribution characteristics of dust retention was analyzed.

Result (1) There were significant differences in leaf dust retention ability among the three plant species, S. chinensis > G. biloba> P. tabulaeformis, with 4.79 ± 0.20 mg.g^-1, 2.48 ± 0.07 mg.g^-1, and 1.42 ± 0.04 mg.g^-1, respectively; (2) The dust retention amount in the three road protection forests changed with the outside influencing factors, and the dust retention of P. tabulaeformis forest had higher stability than that of the other two species. (3) The amount of dust retention increased when the rainfall was less, and decreased when rainfall became more. The dust retention of P. tabulaeformis and G. biloba forests was more susceptible to rainfall. With the increase of wind speed, the dust retention of three road protection forests was strengthened continuously. When wind speed continued to increase, the amount of dust retention of P. tabulaeformis and Sabina chinensis forests decreased, while that of G. biloba forest significantly increased. (4) The amount of dust retention in the three forests was higher in the north side of the Fifth Ring Road than that in the south of Xiangshan Road. The dust retention in the middle position of P.s tabulaeformis and S. chinensis forests was the lowest, while that in the middle position of G. biloba forest had higher volume. (5) The change of dust retention in the outside part of P. tabulaeformis and S. chinensis forests was more active than that in the interior, while the change of dust retention in interior G. biloba forest was more active than the outside part.

Conclusion Dust retention efficiency of road protection forests is affected by tree species, forest structure, environment and weather conditions. In the construction and management of urban plants, relevant factors should be taken into account to achieve full dust retention effect.