Download Introduction Hill fires are one of the major threats to vegetation in

Science in Hong Kong: Volume 3, Spring 2006 p1
From barren land to a green countryside- the application of forest
restoration method in Hong Kong
by Lam Yuk Chi
Introduction
Hill fires are one of the major threats to vegetation in Hong
Kong countryside (see fig.1). In the past ten years, there
were 166 cases of hill fires on average each year, most of
which occurred during the dry season1. Hill fires burn a lot of
vegetation, destroy many wild animal habitat and sometimes
even destroy human lives. In order to restore the lost
vegetation, a traditional method of planting fire-tolerant
exotic species has been used for almost a decade2.
However, it is now being replaced by the more advanced
forest restoration method, as the latter serves more
Fig. 1: Sing Mun Country Park after a hill fire
purposes and is more efficient in aiding the regeneration of
the original biota3.
in January, 2006
© Lam Yuk Chi
Forest restoration method, an advanced strategy in reforestation
The natural recovery of barren land to a secondary forest is slow and
thus needs human interference to speed up the process3. The
traditional method focuses on recovering the abiotic factors that
favour the growth of the original vegetation2. Monocultures of fastgrowing, fire-tolerant exotic species are extensively planted on
degraded land to improve soil condition4. The most frequently planted
Fig. 2: The Acacia confusa
exotic species include the Acacia confusa (Fig.2), A. auriculiformis,
© Lam Yuk Chi
Science in Hong Kong: Volume 3, Spring 2006 p2
A. mangium, Lophostemon confertus, Melaleuca quinquenervia and Eucalyptus spp4. The traditional
method, however, is not effective and places the local the local biota at a disadvantage. Singlespecies’ plantations serve poor biodiversity and are not attractive food sources to native animals4. In
addition, the exotic plants may become potentially invasive and this has devastating effects on the
ecosystem5 in the future.
The advanced forest restoration method, in contrast, does not only aim at improving soil condition but
also takes into consideration the biotic factors that fit local condition and which favour native animals2 .
The forest restoration method considers the entire process of forest restoration which can be simplified
into 3 stages6. The first stage, reclamation, is the recovery of the original biota and the productivity of
the habitat on degraded land6. This can be achieved by planting the right plant species in the affected
sites5. The second stage, rehabilitation, involves the process of reclamation until the ecosystem
becomes fully functional6. The final stage, restoration, is the process by which a young secondary
forest develops into a mature forest which is close to or fully reformed to the original state of the
ecosystem6. The first two stages involve human interference where suitable plant species are planted
on the sites to catalyze the regeneration process while the final stage is achieved through a natural
process6. After the three stages are completed, forest restoration can be achieved.
Application of forest restoration method in Hong Kong
The forest restoration method has been applied in Hong Kong since the late 90’s2. Species planted on
the degraded sites were crucial to the success of the whole method. The species that are selected for
the scheme have to fit into the three most important criteria: being native species, able to survive on
the sites and can attract wildlife7.
Science in Hong Kong: Volume 3, Spring 2006 p3
For the first criterion, mix-planting of native species can increase the structure complexity of the
habitat and thus provide more food sources for local animals7. Secondly, the native species have to be
tough and be able to survive and grow well on degraded sites8.
These species are often treated as ‘pioneer species since their
establishment improves soil conditions which in turn allow the
introduction of other native species8. The third criterion is the
attractiveness of the species to local wildlife8. This refers to species
that can provide abundant food source for animals. For instance,
species which bear fleshly fruits can attract important seed
dispersers like the Chinese Bulbuls8 (see fig. 3). The seed
dispersers increase the efficiency of establishing new pools of
Fig. 3: The Chinese bulbul © Lam
Yuk Chi
species on the sites and result in population developing more rapidly.
Under local screening procedures, native species are selected and grown in a nursery and their
seedlings transferred to the sites that need to be restored8. Examples of suitable native species are
Rubus reflexus (see fig. 4), Sterculia lanceolata (see fig. 5) and Melastoma sanguineum8 (see fig. 6).
Only a small proportion of the exotic species which are more tolerant to hill fires will be used on
heavily degraded sites or sites that are frequently disturbed by hill fires2.
This increases the
effectiveness of the regeneration process and more planted species will be able to survive.
Fig. 4: Rubus reflexus © Lam Yuk
Chi
Fig. 5: Sterculia lanceolata ©
Lam Yuk Chi
Fig. 6: Melastoma sanguineum ©
Lam Yuk Chi
Science in Hong Kong: Volume 3, Spring 2006 p4
Conclusion
The forest restoration method has been applied in the Hong Kong countryside in order to regenerate
sites that are destroyed by hill fires. Selecting the right species to plant on the sites is the most
important factor to consider when carrying out the method. Native species that are able to grow on
degraded sites and attractive to wildlife are best suited for the scheme. The restored vegetation helps
bring back the original forest and ecosystem. It can also recover the greenery of the countryside and
help prevent the occurrences of hill fires. This will protect and save both humans and wildlife.
Science in Hong Kong: Volume 3, Spring 2006 p5
References
1. HKnature. 2006. The control of hill fire. Available from
http://www.hknature.net/chi/resources/webclass/hillfire/. Accessed 2006 Mar 18.
2. HKnature. 2006. More than trees- the story of reforestation. Available from
from http://www.hknature.net/eng/habitate/index2.html. Accessed 2006 Mar 18.
3. Lamb, D., P. Erskine and J. Parrotta. 2005. Restoration of degraded tropical forest landscapes.
Science 310 (5754): 1628 – 1632.
4. Corlett, R.T. 1999. Environmental forestry in Hong Kong: 1871-1997. Forest Ecology and
Management 116: 93-105.
5. MacKinnon, J. 2003. Invasive Alien Species in Southeast Asia. In Proceedings of a Workshop for
Forging Cooperation Throughout South and South East Asia, Prevention and Management of
Invasive Alien Species: The Global Invasive Species Programme: Bangkok: Thailand: p 42.
6. Brown, S. and A.E. Lugo. 1994. Rehabilitation of tropical lands: a key to sustaining development.
Restoration Ecology 2: 97-111.
7. Suding, K.N., Gross K.L. & G.R. Houseman. 2003. Alternative states and positive feedbacks in
restoration ecology. Trends in Ecology and Evolution 19: 46-53.
8. Hau, C.H. 1997. Tree seed predation on degraded hillsides in Hong Kong. Forest Ecology and
Management 99: 215-225.
Acknowledgement
Special thanks to Dr. Billy Hau for his lecture on Terrestrial Ecology: exotic plantation and reforestation
in the countryside.