In recent years, the impact of surface heat islands in urban street canyons has become increasingly apparent. However, the research on the use of trees to mitigate surface heat islands remains limited. To address this gap, this study combines experiments and simulations to analyze the cooling effect of trees on surface temperatures under varying timeframes and layouts in an east–west street canyon. The results reveal that the temperature of the road decreases by 10–15 °C, which is 2–4 times greater than that on the south side. Moreover, at 5:00 p.m. in the afternoon, the cooling effect on the south side is 10.3 °C, which is twice that of the north side. In practical planning and design, the diameter of the tree canopy should be maximized, and trees with leaf-area densities greater than 1.5 m²/m³ should be selected. Additionally, the layout of trees should be optimized to maximize the tree canopy coverage. These findings have important implications for optimizing plant selection and placement in street canyons.

Traditional wooden dwellings, which are widely distributed with enormous stocks in China, are of great historical and have obvious cultural value. The walls of such buildings are generally subjected to poor thermal insulation performance, which not only reduces residential thermal comfort but also increases building cooling and heating energy consumption. In addition, buildings of this type have been subjected to all kinds of problems, such as the lack of measures for improving thermal comfort and the shortage of special funds. Consequently, it is very challenging to reutilize Chinese traditional dwellings, many of which are abandoned and even collapsed. All of the above have become major difficulties encountered in the traditional dwelling heritage protection. Hence, investigating the energy-efficient retrofitting strategies for traditional dwellings and giving economical evaluation methods are two keys to solving the reutilization problem of traditional dwellings. Against this background, a set of second-level evaluation methods for the energy-efficient retrofitting of Chinese traditional dwellings are proposed in this research, including the survey on retrofitted dwellings, the retrofitted dwelling modeling and energy consumption analysis, the definition of wall retrofitting scheme, the first-level evaluation of dwelling retrofitting, the second-level evaluation of dwelling retrofitting, and the screening of the wall retrofitting scheme. The first-level evaluation, which took energy efficiency as a reference index, could evaluate the energy conservation effect before and after dwelling retrofitting. With the payback period as the reference index, the second-level evaluation could assess the overall economic efficiency of dwelling wall retrofitting. An appropriate dwelling wall retrofitting scheme could be screened by integrating first-level and second-level evaluation indexes. Then, this scheme was applied to evaluate the wooden wall retrofitting scheme of a typical traditional dwelling in Yapan Village, Zhejiang Province, China. It was discovered through a comparative analysis that if used to reconstruct dwellings in Zhejiang and other places, the combined materials of XPS board and wood-bamboo could not only effectively improve the energy efficiency but also has good economic efficiency. Meanwhile, problems such as the condensation of wooden walls and their construction thickness could be solved by controlling the material thickness. The above research is of guiding significance for the energy-efficient retrofitting of traditional wooden dwellings in the hot-summer and cold-winter zone of China, and moreover, it can provide reference for the energy-efficient retrofitting of traditional wooden dwellings in other climate zones of China.