Although trees are widely planted in paved lands, for examples of roadsides, squares and parking lots, for improving urban environment, the growth and health of trees are impacted by hot and drought stresses because pavement could increase land surface temperature and alter soil moisture condition. In this study, we investigated the trees growing in 108 paired sites of paved and vegetated lands for five commonly planted tree species: ash (Fraxinus chinensis), pagoda tree (Sophora japonica), gingko (Ginkgo biloba), plane tree (Platanus acerifolia) and pine (Pinus tabulaeformis), in squares within parks and roadsides in Beijing, China. Then tree growth and health are statistically analyzed for assessing how severity the impacts are in field
Results/Conclusions
Land surface temperature were significantly higher in paved land than in vegetated land in both square and roadsides for all five tree species, while soil moisture were significantly less in paved land than in vegetated land only in squares for ash, pagoda and gingko species. Tree diameter at breast high (DBH) and height were significantly reduced in paved land as compared with that in vegetated land for gingko and pine in parks. In roadsides, tree DBH was significantly lower in paved land than in vegetated land for gingko while tree height was significantly lower in paved land than in vegetated land for plane tree. The reductions in tree DBH and height are closely related with the increases in surface temperature as well as the decrease in soil moisture. Trees in paved land are also found easily to be damaged by vandalism and insects. These findings confirmed that trees have been negatively influenced when grown in paved land. However, these influences are specific to tree species. So in tree planting in urban paved land, we should give favors to tolerant tree species and provide necessary management such as irrigation or land surface shading.