Evaluation of urban forest landscape health: a case study of the Nanguo Peach Garden, China

Urban forests are important as they provide recreation areas and offer ecological services. Both functions determine the status of an urban forest and reflect contradictory aspects of forest tourism development and environment conservation. However, assessment of urban forest health status at a landscape scale remains scarce. Here, we selected the Nanguo Peach Garden, China, as the study area. Urban forest health status at the landscape scale were classified into recreation and eco-conservation services. Sustainability was quantified using the principal component analysis and the Kriging method to map the landscape classification in the study area. With regard to landscape recreation sustainability, some 18.9% of the total study region was classified as "very good". They were mainly distributed in the north, southwest, and southeast parts of the study area. The central and southeast regions, accounting for 9.5% of the total area, were classified as "very good" for eco-conservation sustainability. Regarding landscape health, the region classified as "very good" accounted for 11.1% of the total study area, and it was mainly distributed in the southern part of the area; the region classified as "very poor" accounted for 16.4% of the total area, and it was located in the northwestern and eastern parts of the study area. With improved landscape health status, the forest/non-forest patch area ratio was increased and the patch number ratio was decreased. A landscape was considered the healthiest when the forest/non-forest area ratio was 0.65 and the patch number was 0.48. The spatial distribution of landscape recreation sustainability and eco-conservation sustainability differed in the Nanguo Peach Garden, and a close relationship was observed between the landscape health and forest landscape internal structure. Forest/non-forest patch area ratios and patch number ratios were relatively stable and constant, suggesting the urban forest landscapes were healthy. The healthiest forest landscapes were mainly distributed in the forest/non-forest transition zone and the unhealthiest forest landscape was mainly located in a single natural forest.