Abstract: In order to testify the environmental effect of urban green spaces with different coverage and multiple layer structure, three typical urban green spaces, i.e., tree-shrub-herbage mixture, tree-herbage mixture, and lawn (treated as a control), in Yuan Da-Du Park in Beijing were selected to measure their microclimate in summer. The air temperature and relative humidity above the green spaces were measured continuously in horizontal and vertical directions. The results showed that during the high temperature period in summer, the air temperature above the green spaces decreased with increasing coverage, but the significant ecological effects of the lowering temperature and increasing relative humidity were not observed until the coverage of the spaces was higher than 60%. The tree-shrub-herbage mixture with higher coverage brought about a wider range of temperature and humidity effect, and had a greater effect on lowering temperature and increasing humidity, compared with the lawn. Reasonable structure and composition of plant community could make the urban green spaces better exert their effects in decreasing temperature and increasing humidity in summer, and thus, be beneficial to the improvement of urban environment and the mitigation of urban heat island effect.

Key words: Bursaphelenchus xylophilus, Antennal sensilla, Volatiles of Pinus, Electroantennogram responses