Abstract
Global warming has intensified the occurrence of dry heatwaves, and the heterogeneous urban habitats can influence trees' tolerance to dry-heat conditions, however the specific mechanisms remain unclear. This research investigated the dry-heat tolerance of nine common trees in Wuhan, a central Chinese city facing persistent heatwave threats, and explored the multifactorial influence of urban habitat variations on trees’ dry-heat tolerance. Diverse habitat sites with the sample plots in various spatial scales were established for each tree species. Dry-heat tolerance was evaluated through visual assessment, measuring the degree of leaf damage during a historic dry heatwave event. A significant interspecific difference was observed in trees’ dry-heat tolerance, with Pittosporum tobira exhibiting the highest dry-heat tolerance, while Prunus × yedoensis displayed the lowest, in relevance to the life forms and provenances of species. And the dry-heat tolerance of trees in a specific species varied across various habitats, influenced by surrounding building enclosure and land cover composition. The Degree of Building Enclosure was the most prominent habitat factor, followed by the Percentage of Canopy Coverage and the Percentage of Grove Area, all of which positively affected tree tolerance, in contrast with the Percentage of Impermeable Surface showing a negative effect. In addition, the scale effect was evident, that the 50m and 100m range were identified as the most effective spatial scale of campus habitats affecting trees’ dry-heat tolerance, especially for the species with weaker tolerance. The findings can support the selection of tree species and optimization of artificial habitats to enhance the heatwave resilience of urban vegetation in central Chinese cities.