关键词: 火烧强度, 土壤有机碳, 火后恢复时间, 大兴安岭

Abstract: In order to make a comprehensive evaluation of ecological health functions of urban park green space to guide the construction of urban green space and green travel, the study selected four structure types of green spaces and 13 different plant configuration modes in Beijing Purple Bamboo Park as the research objects. A quantitative assessment of ecological health functions of four ecological health factors: negative air ions concentration, human comfort degree (referring to temperature, humidity and wind speed), PM_2.5 concentration and noise level were carried out both in single and comprehensive ways. The results showed that in spring and summer, all the green spaces could improve the negative air ions concentration, and the diurnal variation of negative air ions concentration showed a singlepeak trend (lower in the morning and evening, higher at noon), the daily variation ranges were 75-750 ions·cm^-3 and 123-1074 ions·cm^-3 respectively. In autumn and winter, the daily variation ranges of negative air ions concentration of green space were small, being 324-527 ions·cm^-3 and 277-523 ions·cm^-3 respectively. The seasonal rankings of negative air ions concentration were summer > spring > autumn > winter. In spring and summer, all the types of green spaces could make the PM_2.5 concentration reduced, while the PM_2.5 concentrations in a few green spaces in autumn and winter were higher than in control. The diurnal variation of PM_2.5 concentrations of green spaces showed a trend of high in the morning and evening, and low at noon. The seasonal variations of PM_2.5 reduction capability were spring > winter > summer > autumn, with a range of reduction of -2.35%-12.02%. The human comfort degree of green spaces was improved in spring and summer, especially in summer, but reduced in autumn and winter. The seasonal rankings of human comfort degree were spring > summer > autumn > winter. All the green spaces could reduce the noise in summer, and the range of net attenuation rate was 0-5.57% and each had its best noise reduction width. Comprehensive analysis indicated that the ecological health function of the arborshrubgrass structure type was the best in Beijing Purple Bamboo Park in summer, followed by arborgrass and shrubgrass, the lawn structure type was the worst. The optimal landscape plant configuration mode was Sabina chinensis + Acer truncatum-Lonicera maackii+ Buxus sinica var. parvifolia + Viburnum sargentii + Amygdalus triloba+ Buxus sempervirens -Carex tristachya.

Key words: soil organic carbon, Great Xing’an Moutains, fire severity, post-fire recovery time