Direct seeding of native species for reforestation on degraded hillsides in Hong Kong

Landslides are common in tropical and subtropical regions with hilly terrains and heavy rainstorms, which cause significant economic, ecological, and social impacts. Natural forest succession is usually slow on landslide scars due to poor soil structure and the lack of seeds of woody plant seeds, and often comes with a higher risk of repeated landslide. Ecological forest restoration has recently been suggested as an effective alternative to restore the exposed landslide scars, however, a comprehensive study to identify effective landslide restoration strategies remains lacking, particularly associated with seed treatment methods and species selection. Here we evaluated the effectiveness of different seed coating treatments of both pioneer and later successional tree species of different seed sizes on seed germination in a one-year study on three landslides in Hong Kong. Our results show that bare seeds had germination rates of 17 to 67% across all selected species (n=7). Biochar-dominant seed coating formulation boosted an additional 9.33 (SE= 0.04) in seed germination rate, while the clay-dominant seed coating formulation did not show significant effect on germination. Our results also show that medium and large-seeded non-pioneer species have significantly higher germination rates than pioneer species. These results collectively suggest that direct seeding using a biochar seed coat is a manageable and useful method to enhance tree seed germination—an essential first step to restore the forests after landslide disturbances in Hong Kong, with potential to be extended to other humid tropical and subtropical forests.

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Introduction of the alien Xenostrobus securis (Bivalvia: Mytilidae) into Hong Kong, China: Interactions with and impacts upon native species and the earlier introduced Mytilopsis sallei (Bivalvia: Dreissenidae)

Marine Pollution Bulletin ◽

10.1016/j.marpolbul.2014.12.046 ◽

2015 ◽

Vol 92 (1-2) ◽

pp. 134-142 ◽

Cited By ~ 22

Author(s):

Brian Morton ◽

K.F. Leung

Keyword(s):

Hong Kong ◽

Native Species ◽

Mytilopsis Sallei ◽

Xenostrobus Securis

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

Forests ◽

10.3390/f12030323 ◽

2021 ◽

Vol 12 (3) ◽

pp. 323

Author(s):

Cody H. Y. Lee ◽

Alvin M. C. Tang ◽

Derrick Y. F. Lai ◽

Amos P. K. Tai ◽

Alan S. L. Leung ◽

...

Keyword(s):

Hong Kong ◽

Ecosystem Services ◽

High Risk ◽

Native Species ◽

Urban Forests ◽

Arrested Succession ◽

Native Forests ◽

Soil Constraints ◽

Exotic Tree ◽

The 1960S

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.

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A Case for Direct Seeding of Woody Species on Highway Roadsides

Journal of Environmental Horticulture ◽

10.24266/0738-2898-5.4.176 ◽

1987 ◽

Vol 5 (4) ◽

pp. 176-179

Author(s):

P. Lloyd Hipkins ◽

James S. Coartney

Keyword(s):

Native Species ◽

Woody Species ◽

Site Preparation ◽

Past Experience ◽

Direct Seeding ◽

Maintenance Costs

The use of woody species on highway rights-of-way is a long standing practice which is coming under closer scrutiny as costs of landscape materials and maintenance increase. Direct-seeding of woody species may be an option to help control establishment costs. The use of native species may help to reduce maintenance costs as well as the mortality experienced with exotic landscape cultivars. Past experience has shown that successful direct-seeding can be accomplished with proper site preparation and planting techniques.

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