Journal of Wildlife and Parks (2014) 29 : 61-67 61

A MODEL OF GREENED EX-TIN MINE AS A LOWLAND BIODIVERSITY DEPOSITORY IN MALAYSIA

Ang, L.H.*, Ho, W.M. & Tang, L.K.

Researchers of Ecophysiogy Branch, Forest Plantation Program, Forest Biotechnology Division,Forest Research Institute Malaysia

*Corresponding author: anglh@frim.gov.my

ABSTRACT

Ex-tin mine is a common landscape in Peninsular Malaysia and it covers approximately 113,000 ha spreading mainly in the states of Selangor and Perak. Forest Research Institute Malaysia has successfully greened an ex-tin mine covering 121.5 ha located in Bidor, Perak. Presently, a 17 y-old man-made mixed stand of 60 forest tree species beautifies the once barren-desert like landscape with lush green vegetation surrounding the mining ponds. The man-made mixed forest was established employing findings from two decades of research activities. The forest is also the man-made habitats that house 70 species of birds and many wildlife species from the diminishing nearby lowland forests located about 10-20 km from the greened ex-tin mine. The two fragmented lowland forests are Bikam Forest Reserve and Chikus Forest Reserve which are located in the fast-expanding economic zone of Batang Padang District, Perak. Avian dispersers brought about 20 primary lowland species to the man-made forest since the last 15 years. This paper demonstrates the rehabilitation technology employed to green an ex-tin mine and also reports the regeneration of the tropical rainforest species brought by avian dispersers in the greened ex-tin mine.

Keywords: Ex-tin mine, Rehabilitation, Restoration, Biodiversity depository, Man-made forest, Wildlife.

InTRoduCTIon

Malaysia is a developing nation, and degraded lands are part of the landscape, just like elsewhere in the whole wide world. Forestland had been cleared for agriculture in Malaysia, and presently, about 6.48 million ha of oil palms, cocoa, coconuts, and rubber continuously provide the tree cover but without the inhabitation of the once rich biodiversity. Degradation in forests resulted in patches of grassland, secondary forest and compacted sites in logged-over forests. In addition, problematic soils including beaches interspersed with swales (BRIS) and ex-tin mines are also part of the landscape in Peninsular Malaysia. Tree planting trials had been carried out by Forest Research Institute Malaysia (FRIM) or formerly known as Forest Research Institute on these degraded sites since 1929. This paper aims to highlight a successful model of greened ex-tin mine and its sustainable natural succession that is mainly brought by avian dispersers.

Ang, L.H., Ho, W.M. & Tang, L.K.62

oBjeCTIveS

This paper aims to highlight the success of greening an impoverished ex-tin mine with forest tree species and quantify the natural succession brought mainly by avian dispersers after the establishment of the planting.

AdveRSe SITe pRopeRTIeS And THeIR IMpRoveMenT

Soil degraded through human activities such as logging to mining and the degree of degradation depending on the anthropological activities, normally less disturbance does not involve in the drastic change of existing vegetation and soil properties. The worst form of degradation is tin mining where complete alteration of soil profiles and soil composition was made to extract tin ore. Man-made mixed species forest of Tin Tailings Afforestation Centre (TTAC) of FRIM Field Station Bidor is the model of greened ex-tin mine. Generally, three main site properties include microclimate, soil and water table level, which adversely change during mining activities.

Microclimate

Microclimate determines ecological patterns in both plant and animal communities and also survival. Its important role is recognized in the ecological research (Shirley, 1945). Adverse microclimate reduces decomposition activity of decomposers and adversely affecting influx of nutrients to the soils. In addition it kills most of the seedlings of tropical rainforest species especially in a barren ex-tin mine.

Soil composition

Soil composition of degraded lands normally does not change much except in the case of ex-tin mine. Most of the human activities in impoverishing forest lands do not contribute to alteration of soil composition. However, mining activity causes a change in the soil composition. Normally, to extract mineral ores from the concentrate of the processed materials, they are subjected to water separation, and produce two extreme soil formations known as sand and slime tailings. Sand tailings have particle size more than 0.05 mm, viz. sand and gravels. The sand and gravel tailings require additional fine soil particles such as silt and clay to improve their soil physical properties for growing tree species.

Mechanical impedance

Main physical properties of sand tailings that require further improvement for growing plants include mechanical impedance. High mechanical impedance > 1.5 MPa is commonly encountered in ex-tin mine and logged-over forests or any form of degradation involving heavy machinery. The mechanical impedance of sand is reckoned to be high and caused impedance to root growth (Ang & Ho, 2004). The compaction introduced to the sand tailings was due to the movement of heavy machines during levelling. High mechanical impedance of sand tailings can be overcome by deep-hole planting technique, followed by an application of peat or organic waste such as empty fruit bunch of oil palm. The average size of the planting hole is 1.5 m length x 1 m width x 1 m depth, and was prepared using an excavator. About 2/3 depth of the hole was filled back with sand particles.

A Model of Greened Ex-Tin Mine as a Lowland Biodiversity Depository in Malaysia 63

unfavorable water table level

Sand tailing is often dry during drought period. Drought period of two weeks will dry up all the available water to 15 cm depth from the surface (Ang et al., 1999). The cause of such evaporative demand effects is mainly due to the particle size distribution of sand tailings which comprises > 90% coarse sand. The high porosity of sand has inverse relationship with its water retention capacity. The main approach adopted in the site preparation of the project site where the sand dunes are situated at > 4 m above surface water level (aswl) was to reduce water loss from the root zone during dry period. The level of sand tailings determines its suitability for rehabilitation and restoration with plant species. If sand dunes are situated more than 4 m above standing water table level (aswl), a drought of two weeks (rainfall < 4 mm day-1) would dry up the available water of the 0-15 cm depth of sand dune (Ang et al., 1999). The dehydrating of sand dune in dry season is mainly due to its high composition of sand and gravel. The high permeability of sand results in low water retention capacity and it is costly to irrigate the timber planting compared to high value production of agriculture produce. Hence, another approach was developed by planting tree seedlings in a pit of lower than 45 cm surface of sand dune situated at 4 m aswl, using a big-hole planting technique; the planting hole of 1 m to 1.5 m deep and 0.5 m to 1 m width and enriched with empty-fruit-bunch of oil palm at the bottom and refilled to 0.45 cm below the surface of the sand dune. This method of planting proves to be a success in establishing dipterocarp and leguminous climax rainforest species on 6 to 10 m sand dunes in Bidor (Ang & Ho, 2004).

Soil chemical properties

Sand tailings have lower concentration of macronutrients and some of the important trace elements compared to the mineral soils as shown in Table 7. The pH ranges from 4.0 to 6.5 for both types of tin tailings (Ang & Ho, 2004). Soil properties of sand tailing have been the main obstacle for enhancing growth and survival of timber tree species. Sand is low in fertility. Many studies showed that introduction of organic fertilizer either from plant materials or animal wastes to sand tailings would improve its fertility and also improve its physical properties. This approach has been used to improve the nutrient status of sand tailings in the project site. Low pH is the main concern for growing timber tree species on slime tailings. Application of ground magnesium limestone (GML) is absolutely necessary, if the ex-mining land is originally a peat swamp forest. The soil pH of the project site is from 4.0 to 6.5, and with the application of about 200 g GML per planting point, the growth of the seedlings was observed to be healthier at one year after planting.

Thick weed cover

Shifting cultivation site and grassland normally have the same problem, the ferocity of weeds especially Imperata cylindrica and Melastoma malabathricum. These weeds render the planting for rehabilitation and restoration purpose meaningless as the roots of the weed and their fast-growth rate suppresses the growth of the seedlings either from harvesting the photosynthetically active radiation or competing for soil moisture and nutrients in the root region. Removing of the weed cover is the main task before planting. Three methods of weeding were practiced in TTAC: manual, mechanical and chemical methods.

Ang, L.H., Ho, W.M. & Tang, L.K.64

A MIxed-SpeCIeS FoReST STAnd on An ex-TIn MIne AT TTAC

Forest Research Institute Malaysia (FRIM) has established a Research Substation at Bidor, Perak with the aims to develop the ex-tin mine into a model of rehabilitated mixed forest stands. The research station is established on tin tailings left by Malaysia Mines Cooperation in 1940s. It is located about 138 km north of Kuala Lumpur and is easily accessible. The extent of the station is about 125 ha and comprising sand tailings, ponds and slime tailings. Ex-tin mine is infamous for its poor site quality for growing plants. High cost of fertilizers and watering are required for turning ex-mines into agriculture uses, and thus limit their large-scale uses. In addition, with the discovery of unacceptably high level of heavy metals in the food crops grown on tin tailings recently has rendered it a less preferable site for food production. Rehabilitation of the degraded land with forest tree species is a better option of land use and would improve the soil properties and also can act as a wood production area. Presently the research station houses a few main timber species namely Malabira (Fagraea crenulata), Akasia (Acacia aulocapa, Acacia auriculiformis, Acacia mangium, Acacia crassicarpa), Acacia hybrid ( Acacia mangium x Acacia auriculifomris), Rosewood (Delbergia longipinnata), Jelutong (Dyera costulata), Merawan siput jantan (Hopea odorata), mahogany (Swietenia macrophylla), African mahogany (Khaya ivorensis) and keladan (Dryobalanops oblongifolia) (Ang & Ho, 2004).The landscape of the former barren land of SPL Bidor has now turned into a lush green mixed forest surrounded by ex-mining land, oil palm plantation and housing estate.

SpeCIeS dISTRIBuTIon And RICHneSS oF TTAC

Based on a study conducted by Ang & Tang (2010), the distribution of all trees with diameter at breast height, dbh > 5 cm in the 20-ha study site of TTAC was mapped (Figure 1). A total of 20 species of regenerated trees were mapped and identified and very little regeneration was quantified at the open site where no trees were planted before, even at the edge of the pool < 4m a.s.w.l (Table 1). However, where a single row of trees were planted, natural regeneration was found under their canopies. High quantity of regeneration reached dbh> 5cm was found within 100 m from the edge of the planted forests. Open sites or unplanted sites remain sparsely colonized by the Acacia hybrid, A. mangium, Vitex pubescence and A. auriculiformis, and also regeneration is widespread under the planted site after 100m but seldom reaches the dbh size of > 5 cm as under the thick canopy mixed-acacias stand planted at 3 x 3 m density that only permits about 20-40% light intensity to reach the ground level.

A Model of Greened Ex-Tin Mine as a Lowland Biodiversity Depository in Malaysia 65

Figure 1. The regenerated species distribution map of the study site

ToTAL nuMBeR oF RegeneRATed TReeS

Figure 2 shows that most of the regenerated species reached the dbh > 5cm were found under the Acacia mangium, Hopea odorata and Acacia auriculiformis stands planted at spacing of 5 x 4 m covering sand dune heights of 8-16 m a.s.w.l., at the fringe of the mining pool, but at the lowest and higher sand dune levels at 0-4 and 20-28 m a.s.w.l., respectively, only a relatively smaller number of species and frequency were noted. Open site at 0-4m a.s.w.l, was colonized by shrubs, grasses, ferns, and patches of acacias saplings and naturally regenerated saplings normally < 5 cm dbh under single trees of Acacia hybrid, Acacia mangium, Acacia auriculiformis Evodia glabra, and Macaranga gigantea. Similarly, very small number of tree species reached > 5cm dbh under the mixed stands of Hopea odorata, Acacia mangium and Acacia auriculiformis, Intsia palembanica and A. crassicarpa situated from 20-28 m a.s.w.l., as the natural regeneration were subjected to regular soil water deficit during drought as the only water supply to the plants was from rain-fed.

Ang, L.H., Ho, W.M. & Tang, L.K.66

Figure 2. The total number of regenerated trees versus mean diameter class spreading within each sand dune level.

SHAnnon Index

Figure 3 shows the shannon diversity index of regenerated tree species on sand dune at various standing water table levels (Shannon, 1948). The Shannon Index (H) peaks at sand dune situated at 10 m a.s.w.l.; similarly, the peak of maximum diversity possible (Hmax) of sand dune is ascertained at the same a.s.w.l., and declined to the lowest at 22 m a.s.w.l. This indicates that highest species richness is found at sand dune situated at 8-12 m ( mean 10 m) a.s.w.l., which is about 72% richer than the species composition at mean 22 m a.s.w.l. The greatest evenness (E) of tree species distribution was found at 0-4 m a.s.w.l. and indicates higher probablity to find any individual of all the species found at the site. The lowest E at the 14 m a.s.w.l. indicates that the number of individual is not evenly distributed within the species composition.

A Model of Greened Ex-Tin Mine as a Lowland Biodiversity Depository in Malaysia 67

3

2.5

2

1.5

1

0.5

0

0 5 10 15 20 25

E

Hmax

H

Mean Standing Water Table Level (m)

Index

Figure 3. Shannon Diversity Index of the regenerated tree species of various sand dune height above standing water table.

ConCLuSIon

The man-made mixed species forests established in Bidor by FRIM witnesses the success of planting technologies and tending techniques in rehabilitation of degraded sites and sustainably maintained till this day. The natural regeneration including 20 species of lowland primary species and mature secondary forest species were brought mainly by avian dispersal agents.

ReFeRenCeS

Ang, L.H. & W.M. Ho. (2004). A demonstration project for afforestation of denuded tin tailings in Peninsular Malaysia. Cuadernos de la Sociedad Española de Ciencias Forestales, 17: 113-118.

Ang, L.H. & Lim K.H. (1997). Species site matching for afforestation of tin tailings in Peninsular Malaysia. In Proceedings of International Conference on Land Reclamation & Rehabilitation, 25-27 August 1997, Golden Sands Resort, Penang, Malaysia, pp. 370-384.

Ang, L.H., Seel, W.E. & Mullins, C. (1999). Microclimate and water status of sand tailings at an ex-mining site in Peninsular Malaysia. Journal of Tropical Forest Science, 11(1): 157-170.

Shannon, C.E. (1948). A mathematical theory of communication. Bell System Technical Journal, 27: 379-423, 623-656.

Shirley, H.L. (1945). Light as an ecological factor and its measurement. Botanical Review, 1: 497-532.

Tang, L.K. & Ang, L.H. (2011). Regeneration composition and distribution at open and greened sites of a 20-hectare ex-tin mine in Peninsular Malaysia. In Proceedings of The International Symposium on Forestry and Forest Products 2010: Addressing Global concerns and Changing Societal Needs, 5-7 Oct 2010, Kuala Lumpur (Gan, K.S., Mahmudin, S. & Mohd Nor, M.Y., eds.).