The status and prospects of urban trees in Hong Kong

Abstract

The status and prospects of urban trees in Hong Kong are evaluated with information gathered from questionnaires and a tree survey. Planting and maintenance responsibilities fall to four government departments plus the private sector. Species composition is unevenly distributed, with five popular species constituting over half of the trees sampled. The numbers of introduced and cultivated trees far exceed those of native and voluntary ones. Species-selection without an evaluation programme is generally conservative, but gradual shifts in preference are discernible. The multifarious physical constraints in both the above-ground and subterranean environments that pose stringent limits on the number of potential planting sites and the growth of existing trees are elaborated. Typhoons, which could periodically cause widespread damage, often regardless of species and location, could only be partially mitigated by more comprehensive preventive measures. Pests and diseases which have not received detailed study are apparently mild. Vandalism, which damages roughly 10–15% of trees planted, could be alleviated by planting more heavy standard trees, but their supply is limited because of inadequate nursery space. The chronic shortage of tree staff aggravated by a high job mobility, due mainly to comparatively low remuneration and poor promotion prospects, creates a bottleneck in the tree programme. For the future, a city-wide tree survey together with a computer database are essential for efficient management, maintenance and research. The existing, rather lax statutory control should be consolidated and tightened, with authority being given to a single department which should be adequately supported by supervisory staff. Land could be zoned specifically, like other land-uses, for tree planting, and this could be more generous and spatially more evenly distributed to allow penetration of greenery into wider parts of the city. The potential in urban renewal areas where land could be released and reserved for planting should be realized as far as possible. Overall, rising aspirations for better environmental quality could be achieved by a combination of high-density vertical developments and strategically situated open spaces liberally adorned by landscape planting.