Problems and Management of Acacia-Dominated Urban Forests on Man-Made Slopes in a Subtropical, High-Density City

Abstract

Acacia spp. are exotic tree species that have been widely planted on man-made slopes in Hong Kong since the 1960s. However, as they become mature and senescent, they may become a concern and cause various problems, including soil constraints for plant growth, decreasing provision of intended ecosystem services, declining syndromes, arrested succession, and high risk of failure. In this perspective paper, we present and discuss these problems using practical examples of Acacia-dominated urban forests on man-made roadside slopes in Hong Kong, based on a cross-disciplinary survey and a literature review. To conclude, we suggest that selective cutting, specific silvicultural operations of Acacia plantations, and the management of plantation edge and soils can be exercised, along with the planting of native species, to potentially alleviate these problems associated with mature Acacia plantations, by promoting the establishment of native forests, enhancing biodiversity, expediting succession, and providing better ecosystem services.

Physiological Characteristics to Indicate Water Use Efficiency and Drought Tolerance of 30 Indonesian Sorghum [Sorghum bicolor (L.) Moench] Accessions

“…Tatsumi et al (2020) conducted a study of ambient light sources to determine the photosynthetic response of rice plants under conditions of continuously fluctuating light intensity. Lee et al (2021) conducted a study using LICOR-6800 to observe the parameters of physiological foliage parameters and the photosynthesis rate of Acacia.…”

Study towards Integrating Secondary Forests into Future Land Use Development in Singapore for Biodiversity Objectives

“…For the forested areas with lower vegetation density and large patch sizes, forest restoration through tree improvement programs such as planting native species and fauna-attractive trees could be introduced to improve the level of biodiversity. This strategy is linked with Lee et al's research in the urban forests of Hong Kong, which indicates the idea that planting native species in urban forests can enrich the biodiversity of these sites [36]. Relevant theory is also mentioned in Abbas et al's research on the secondary forests of Hong Kong, in which the necessity of introducing late-succession species for ecosystem restoration in tropical secondary forests is emphasized [25].…”