Impacts of pavement on the growth and biomass of young pine, ash and maple trees

Pervious pavement showed lower inhibition on tree growth and biomass than impervious pavement and ash is more tolerant and more suitable to be planted on pavement than pine and maple. Trees are widely planted on paved soil in urban environments. However, little is known about the effects of altered microenvironments on the growth and biomass of trees. In this study, seedlings of three common urban trees, pine (Pinus tabuliformis Carr.), ash (Fraxinus chinensis Roxb.), and maple (Acer truncatum Bunge) were planted on pervious and impervious pavements for over 6 years. Unpaved soil was used as a control. Pavement significantly increased surface and soil temperatures, and altered soil moisture. Pervious pavement had higher surface and soil temperatures and soil moisture than impervious pavement. Compared with the control, tree biomass significantly decreased by 27.1–40.7% for all the three species under impervious pavement, while tree biomass significantly decreased by 28.6% only for maple under pervious pavement. Tree biomass was negatively related to soil temperature and positively to soil moisture. Heat stress caused by pavement could be alleviated as trees grow because of the progressive shading of tree canopy. Management practices such as prevention of heat and drought stresses, selection of tolerant species and use of pervious pavement should be advocated for promoting urban greening.