Since January 2008 HUTAN has engaged in a project to rehabilitate crucial orang-utan habitat in the Lower Kinabatangan. The project aims at recreating forest corridors for wildlife.
Forest degradation and fragmentation in the Lower Kinabatangan region are the major threats to the long-term survival of wildlife and proactive measures are the key to success. Past logging activities have at places resulted in the destruction of the seed bank contained in the soil and have compacted the soil thus preventing natural forest regeneration. In order to recreate corridors for wildlife, particularly orang-utans, native, fast-growing tree species are to be planted.
Four village women were hired and trained for the initial phase of this project. Three plots were selected in the Lot 2 of the LKWS and a total of 1,752 seedlings were planted of 6 different tree species known to be commonly consumed by orang-utans at the HUTAN’s Sukau Research site (i.e.Dracontomelon dao, Octomeles sumatrana, Microcos sp, Mitrogyana speciosa, Diospyros sp, Neonauclea sp.). The survival and growth rates of the planted seedlings were monitored monthly. It was established that while some species prefer dry open areas, others survive and grow better in shaded humid areas. Octomeles sumatrana(or “Binuang”) was the fastest growing species with an average growth of 36.5 cm per month. Trampling by elephants and predation by pigs, deers, snails, caterpillars and other insects mostly caused seedling mortality.
To prevent the elephants to destroy the seedlings, each plot had to be protected by an electric fence. We also valued the seedling needs for maintenance such as weeding to ensure optimal survival and growth (frequency and methods of weeding).
Previous tree planting experiments by HUTAN showed that a minimum of 2 to 3 years of regular weeding around the trees planted is needed. It therefore appears that the overall costs for efficient forest rehabilitation are much higher than the mere cost of the seedlings, mostly because the maintenance needs (workers’ salary, boats and petrol to access the plots, electric fences) to ensure the survival of the young trees are high.