Urban tree planting and management in public housing estates in Hong Kong

Abstract

Greening is a global trend in urban development. Hong Kong Public Housing Estates (PHEs) are distributed all around in Hong Kong urban area which contributes to large area of urban greening and tree planting is one of the elements in urban greening. Trees can bring massive benefits to society in terms of environmental improvement and social adherence. This study evaluated species composition in 10 urban PHEs (5 Old and 5 New PHEs), species specific characteristics and post planting maintenance quality in 5 urban PHEs in Hong Kong. These aim to identify the changes in species composition and quality of maintenance works. A total of 2245 trees were recorded including 945 trees in Old PHEs and 1245 trees in New PHEs. Size of trees skewed from medium to small sized tree. There are large increases in selecting palm tree species as percentage has increased from 10% to 35.5%. However, percentage of native tree species dropped from 27.8% to 10.1% in the top twentieth tree species. Besides, some trees species especially Hibiscus tiliaceus is not recommended planting in housing estate due to its poor structural nature. Lastly, maintenance quality has improved since there are large percentage of reduction in defects resulted from improper pruning. Small sized tree and palm tree species should be in the first priority in tree selection as spaces are insufficient in urban area. However, large sized species should also be considered when planting spaces are sufficient because of functional concern and enhancing biodiversity. Besides, more native tree species should be selected in future as this can enhance the local ecology and environmental condition. Lastly, things should be done in order to enhance the quality and acceptability of arboriculture industry in Hong Kong such as introducing accreditation system.