Health status of landscaping trees in different habitats in Beijing, China.

The health of urban trees is jointly influenced by species-specific environmental adaptability and habitat heterogeneity, posing severe challenges for management. We investigated landscaping trees in Beijing, established a five-tier health evaluation system (healthy, sub-healthy, unhealthy, severe decline, and moribund) comprising 14 indicators. Then, we analyzed current health status and the influence of six typical habitats: dense forest, sparse forest, tree belt, tree pond, waterside, and buildingside. A total of 3654 trees were surveyed, which belonged to 80 species, 44 genera, 27 families. 71.7% of the trees were rated as sub-healthy or worse. The top 10 species by number of samples (46.3% of total) showed significant health variations. Ginkgo biloba, Platanus ×acerifolia, Ailanthus altissima, Catalpa bungei, and Pinus tabuliformis were classified as sub-healthy, while Styphnolobium japonicum, Fraxinus pennsylvanica, Populus tomentosa, Koelreuteria paniculata, and Prunus cerasifera 'Atropurpurea' were classified as unhealthy. G. biloba exhibited optimal performance in dead branch rate, crown form, and trunk injury severity. P. ×acerifolia exhibited optimal performance in foliage disease and pest severity, foliage density, trunk inclination degree, and tree vigor, whereas P. cerasifera 'Atropurpurea' showed the poorest performance in foliage disease and pest severity, leaf discoloration, and tree vigor. Tree health varied significantly across the six habitats, ranked as sparse forest > dense forest > waterside > buildingside > tree belt > tree pond. Trees in spare forest habitat exhibited favorable overall healthy. Dense forest habitat exhibited notable crown form deficiencies. Waterside habitat suffered higher foliage disease and pest severity. Buildingside habitat exhibited pronounced leaf discoloration. Tree pond habitat exhibited marked tree vigor decline. In conclusion, Beijing landscaping trees faced substantial health risks, G. biloba and P. ×acerifolia demonstrated strong urban adaptability, while P. cerasifera 'Atropurpurea' exhibited sensitivity; sparse forest habitat provided optimal growing conditions, whereas tree pond habitat imposed the most significant constraints on tree health.