Tree Composition and Diversity of a Hill Dipterocarp Forest after Logging

Malayan Nature Journal 2014, 66(4), 1-15 Tree Composition and Diversity of a Hill Dipterocarp Forest after Logging SEYED MOUSA SADEGHI1,2, I. FARIDAH-HANUM1*, WAN RAZALI, W. M. 1, KAMZIAH ABD KUDUS1 and KHALID REHMAN HAKEEM1 Abstract: Logging operations have been known to highly influence the environment of tropical rain forest. The present study investigated the effect of supervised logging (SL) operations on tree composition and diversity of a hill dipterocarp forest (HDF) in Ulu Muda Forest Reserve, Kedah, Peninsular Malaysia. To describe the tree composition and diversity of the secondary HDF after SL, the compositional factors and diversity were analyzed. A plot of size 1-ha was established. All trees with diameter at breast height ≥ 1cm in 10 sub plots (50m × 20 m) were enumerated, measured and identified. In the study site, we recorded 891 individuals, belonging to 56 families, 158 genera, 296 species and one variety. Ten families provided 55.7% of the total species composition. Euphorbiaceae has the highest number of species and was followed by Lauraceae, Rubiaceae, Annonaceae and Meliaceae. With regards to relative dominance, Diplospora malaccensis (Euphorbiaceae) gave the highest importance value index for species and family, respectively. Shannon-Wiener’s index was high with a value of 5.3. Ulu Muda Forest Reserve is high in endemism with a total of 27 endemic species recorded. Two rare species which are Symplocos calycodactylos and Alseodaphne garciniicarpa and one very rare species, Cleistanthus major were found here. Diospyros argentea was also found to be a new record for Kedah. Keywords: Tree composition, diversity, hill dipterocarp forest, and logging. INTRODUCTION The environment of a tropical rain forest was known to be affected by logging operations strongly (Burgess, 1971; Saiful, 2002; Okuda et al., 2003; Akkharath, 2005). The reaction of tropical rain forest towards both anthropogenic and natural disturbances is one of the most crucial aspects in ecological studies (Lugo and Brown, 1986; Grace, 2004; Chave et al., 2005). 1Faculty of Forestry, Universiti Putra Malaysia, Serdang 43400, Selangor, Malaysia 2Natural Resources and Agricultural Research Center of Bushehr Province, I.R.Iran * Corresponding Author: i.faridahhanum@gmail.com The number of families, genera and species of Ulu Muda Forest Reserve ( UMFR) was found to decrease after logging from 49 to 43 families, 136 to 124 genera, and 270 to 205 species, respectively (Saiful, 2002). The protection of primary forest is significant for biodiversity conservation and climate change mitigation; the secondary forest must also be considered for the same crucial roles (Berry et al., 2010). Countries such as Indonesia and Malaysia have considered changing the logging approaches from CL to supervised logging (SL) (Sist et al., 1998). In SL, all activities were done under the supervision of “Supervisory Field Team” to reduce the impact of logging on forest ecosystem during the logging period (Sist et al., 1998). The benefit of SL compared to CL was to reduce damage to the ecosystem of the forest to below 50% (Sist et al., 1998). In the year 2000, compartment 25A of UMFR was subjected to SL operations to manage these forests under sustainable forest management approaches (Saiful, 2002). Forest composition of HDF was strongly affected by selective logging operation immediately after logging (Saiful, 2002; Kamziah et al., 2011). Conventional logging activities had declined the taxonomic composition of the HDF of UMFR (Saiful, 2002). The family Dipterocarpaceae was the most affected dominant family after logging in UMFR (Saiful, 2002). The performance and demography of selectively logged tropical forest were influenced by logging operations after 40-50 years (Yamada et al., 2013). Likewise, the fast growing species were abundant in the secondary forest compared to the old growth forest (Okuda et al., 2003). The intensity of logging operations affected the biodiversity of the tropical rainforest (Imai et al., 2013; Saiful & Latiff, 2014). Biodiversity of HDF was affected by land use management activities. Saiful (2002) reported that Shannon Weiner’s index sharply decreased after CL in habitats such as hillside, ridge and ridge top for all diameter at breast height (DBH) size classes. Having a true understanding of floristic composition of the successional secondary forest after disturbances would be crucial for considering forest recovery procedures and planning forest management. Forest succession is changes in plant community over the passage of time. The process of succession could be progressive or regressive (Ellenberg and Mueller-Dombois, 1974). The vegetation succession was classified into three main groups: Phenological vegetation changes, Secondary succession, and (3) Primary succession (Ellenberg and Mueller-Dombois, 1974). Succession following logging is the secondary succession (Kimmins, 2004). The presence or absence of residual vegetation and their propagules which survive the disturbance is the most important factor in forest succession (Turner et al., 1998). Likewise, size and intensity of disturbances can strongly influence the succession potential of the regenerated forest (Van Gemerden et al., 2003). Furthermore, severity of disturbances, matrix of landscape, proximity of degraded forest to remnant forest areas, and soil 2 fertility can also influence forest succession (Chazdon, 2003). Additionally, different species might be established in different regions (Ellenberg & Mueller-Dombois, 1974). The present research aimed to quantify the tree composition and forest diversity value of Ulu Muda Forest Reserve in Kedah, 12- years after supervised logging. It is part of an ongoing assessment on a 5-ha study plot to be reported in another paper elsewhere. MATERIALS AND METHODS Study area The research was carried out in the HDF of UMFR, Compartment 25 A (Figure 1) at altitude of 419-555 m above sea level in the state of Kedah, Peninsular Malaysia (5, 50’ N & 100, 55’ E). The average annual precipitation and temperature of the site were 2869 mm and 26-29◦C (Lim, 1991; Saiful et al., 2008). In terms of geology, UMFR includes three geologic formations, The Kulim granite, Bintang granite formation, Semangol formation, and Baling formation as the basic levels of the ground habitats (Lim, 1991). The main type of soil in the study site was ultisols (Saiful 2002). The total area of compartment 25A was 232.09 ha. The original vegetation type was dominated by dipterocarps (Faridah Hanum et al., 1999; Saiful et al., 2008). Supervised logging operations began in Compartment 25A in 2000 and ended in 2001 (Akkharath, 2005). Methodology Data were collected from 10 sampling plots totalling 1- ha was laid out systematically in the supervised logging (SL) site (Fig. 1). All trees with diameter at breast height ≥ 1cm in 10 subplots each of size 50m × 20 m were enumerated, measured and identified. Taxa identification was based on (Whitmore, 1972 ; Whitmore, 1973; Kochummen, 1978; Ng, 1989; Turner, 1995; Symington et al., 2004). The species composition and diversity of forest stand were analyzed. For species richness, the rarefaction method and Jacknife approach were used. The rarefraction method used followed Krebs (1999) as shown below: Where E (Ŝn) = Expected number of species in random sample of n individuals 3 S = Whole number of species in the entire collection Ni = Quantity of trees of species i N = Overall amount of trees in collection = ∑ Ni N = Value of sample size (number of individuals) chosen for standardization (n ≤ N) ( ) = Number of combination of n individuals that can be chosen from a set of N individuals = N!/n!(N-n)! The Jackknife estimator approach (Krebs, 1999) was used to estimate the maximum value of species richness as follows: ( ) Where Ŝ = Jacknife estimate of species richness s = Observed total number of species in the n plots n = Total number of sampling units k = Number of unique species The species diversity and richness4 (SDR4) software was used for calculating the diversity and richness of the forest stand (Seaby & Henderson, 2006). The most common indices for diversity evaluation were calculated as follows; Simpson’s index is 1-D (Simpson, 1949; Krebs, 1999): ∑( ) Where ni = Number of individuals of species i in the sample N = Total number of individuals in the sample s = Number of species in the sample The Shannon-Wiener’s index (H) is (Pielou, 1966): 4 ∑ Where s = Number of species and ρi= proportion of total sample belonging to ith species Margalef index could evaluate the richness index of stand (Clifford & Stephenson, 1975): DMG Where S = Number of species, N = Total recorded number of individuals Alpha Fisher’s index (Fisher et al., 1943) of diversity (α): S= Where S = Total number of species in the sampling area N = Total number of individuals in the sampling plot α = Index of diversity Additionally, Smith & Wilson (1996) evenness index was calculated as follows (Krebs, 1999): ∑ [ ( ∑ ⁄ ) ⁄ }] { Where E = EVar = Smith and Wilson’s index of evenness (Krebs, 1999) ni= Number of individuals in species I in sample (i = 1, 2, 3, . . . s) nj = Number of individuals in species j in sample (j = 1,2, 3, . . . s) 5 s = Number of species in entire sample Furthermore, evenness index estimation was done by Pielou (1975) model: Where H’ is the real value of evenness, and H max is the exactly maximum potential evenness in the study area. The above mentioned models were used to calculate the evenness value of the study site. The importance value index (IVI) of each species was computed according to Curtis & McIntosh (1951) as follows: RF = RD RDo The basal area (BA) of each individual was calculated as follows: BA (m2) = [π × (DBH)2]/40000 The family importance values (FIV) of forest stand were also computed based on (Mori et al., 1983). The FIV was the summation of relative diversity (RDi), relative density (RDe) and relative dominance (RDo): RDi RDe RDo The total tree numbers in all plots were used to generate an average of the stand density ha-1 (Valappil and Swarupanandan, 1996). RESULTS Tree species composition analyzed for 1- ha of the supervised logged-over HDF showed there were 891 individuals belonging to 296 species and one variety in 158 genera and 56 families. Ten families in terms of species composition provided 55.7 % of total species composition (Table 1). The most diverse family was Euphorbiaceae with 44 species in 16 genera 6 followed by Lauraceae, Rubiaceae, Annonaceae and Meliaceae. Although the family Dipterocarpaceae was not among the 10 top families (Table 1), there were still 25 individuals from five species. The non-dipterocarp group contributed 98.3% of tree composition; 62.6% of total species were presented by ≤ 2 individuals in the study site. Twenty seven endemic species comprising 9.1% of the total number of species were found in the study site. These belong to 24 genera from 20 families. In terms of species diversity, the most diverse family was Euphorbiaceae (18.5%), followed by Lauraceae (11.1%), Anacardiaceae (7.4.0%), Burseraceae (7.4.0%) and Annonaceae (3.7%). Results showed there are 27 endemic species in the study site. Based on Ng et al. (1990), two are rare species viz. Symplocos calycodactylos and Alseodaphne garciniicarpa are considered rare while Cleistanthus major very rare. Diospyros argentea is a new record for Kedah (Table 2). Quantitative analysis of the most dominant species (20 species) is presented in Table 3. In terms of relative dominance, 20 species contributed 22.8% and 44.1% of the total density and total basal area of the logged-over stand. Moreover, in terms of basal area, the most dominant species was Diplospora malaccensis (14.7%) followed by Shorea macroptera (13.7%), Ochanostachys amentacea (11%), Shorea kunstleri (9.5%) and Sapium baccatum (7.2%), respectively. The highest IVI was Diplospora malaccensis followed by Shorea macroptera, Ochanostachys amentacea, Mallotus kingii and Macaranga hosei (Table 3). A total of 121 species with one individual were presented in the study site. Likewise, in terms of FIV, ten families provided 6.2% of the total relative density. Euphorbiaceae also contributed the highest value of FIV, followed by Rubiaceae, Lauraceae, Annonaceae and Fagaceae. The minimum value of FIV was contributed by Elaeocarpaceae (Table 4 and Figure 3). In general, the species accumulation curve showed the increasing trend; as the sampling area increased from 0.1 to one ha in the study site (Figure 4). Additionally, it slightly increased from plot 2 (SL7/P1) to plot 3 (SL8/P3). The overall tendency of that curve did not achieve an asymptotic condition. Rarefaction method showed that an increase in the sample size led to an increase in the number of species. When the number of individuals was 89, the estimated number of species was 71.2. However, with 890 individuals the estimated (finite estimation) value of species richness was 296.9 (Figure 5). The jackknife estimation model demonstrated that an increase in the number of samples led to an increase in the number of estimated species (Table 5). Data showed that when this model was used with one plot data, the predicted value of species richness was a minimum. However, the maximum value of the estimated species richness was predicted when the ten plot data were used in the model. 7 Our results showed that the biological diversity of the logged-over was high. The overall Shannon-Weiner’s H index was 5.3 and the MacIntosh’s index and evenness were 0.95 and 1.0, respectively. The lowest and highest value of Shannon-Weiner’s Index was related to sampling plots SL7/P3 and SL9/P2 which were 2.4 and 4.3 (Table 7). The number of individuals in SL7/P3 and SL9/P2 was 18 and 130, respectively. Results of the Smith and Wilson’s evenness method showed that the highest and lowest values of evenness were related to SL7/P2 and SL6/P2 (Fig. 6) which were 0.9 and 0.8, respectively. However, the average value of evenness was 0.7 (Table 6). DISCUSSION In the sampling plots, there were no big trees because they were cut for commercial purposes. However, many studies have indicated that the primary HDF includes trees of all sizes ranging from DBH<1cm to ≥ 100 cm (super tree), (Whitmore and Burnham, 1984; Saiful, 2002). Therefore, the findings of the study should be interpreted in light of this limitation. Additionally, one of the most prevalent tree species in the HDF is Shorea curtisii ssp. curtisii (Whitmore and Burnham, 1984), but a very small number of this species was found in the logged-over forest due to logging. According to Whitmore and Burnham (1984) and Symington et al. (2004), the primary HDF was dominated by trees such as Shorea curtisii ssp. curtisii, Shorea laevis and Shorea multiflora. Indeed, such trees were quite scarce in the sampling plots. In terms of species richness, the supervised logged-site (Compartment 25 A) was richer than unsupervised-logged compartment (28 A), (Mardan et al., 2013) of UMFR. In the SL area, 891 individuals, including 296 species and one variety belonging to 157 genera and 56 families, were found. Furthermore, Mardan et al. (2013) showed that 1- ha unsupervised logged HDF (= conventional logging or CL) of UMFR consisted of 722 individuals belonging to 128 species, 81 genera and 42 families. Likewise, Euphorbiaceae contributed the most number of species in both sites. In general, tropical rain forests of southeast Asia are rich in species composition (Whitmore and Burnham, 1984). Our results were in line with other available studies regarding the tree composition in tropical rain forest (Table 8). Moreover, the high level of species diversity was also observed in the logged-over HDF (Faridah -Hanum et al., 1999; Mardan et al., 2013). Kimmins (2004) observed that in the secondary succession, the establishment of pioneer species is the first stage of succession. Similarly, in the study site pioneer species from the families Dilleniaceae, Euphorbiaceae and Moraceae were recorded because past anthropogenic disturbances created a new environment for light demanding species including Macaranga hosei, M. gigantea, M. triloba, M. hypoleuca, M. recurvata, M. setosa, Croton argyratus, Mallotus kingii, Artocarpus rigidus, Buchanania sessifolia, Dillenia sumatrana, Epiprinus malayanus and 8 Helicia attenuata due to gap formation (SL7/P3 & SL8/P3) in the forest (Figure 7). Moreover, changes in the physical, chemical, and biotic environments, which had been produced by residual organisms, caused replacement of community by new individuals (Kimmins, 2004). In the study site, light demanding species were highly established. They accounted for the high diversity in the disturbed area usually due to gaps caused by logging activities. Ellenberg and Mueller-Dombois (1974) reported that a small number of big size trees showed higher levels of dominant species than young pioneer small sized species which were abundant in the secondary succession. Similar results were recorded in our study site. At the species level, big sized trees from Shorea with small number of individuals presented higher value of IVI than pioneer species which had a larger number of individuals with smaller sized DBH. However, at the family level, data showed that combination of the early successional species from Euphorbiaceae provided the highest value of FIV since in the gap area resulting from logging operations the fast growing species maintained themselves faster than shade-tolerant trees. There was no asymptote of the accumulated species curve (Figure 4). The increasing curve indicated that unsampled species were still in the population (Bacaro et al., 2012). In other words, the sampling must increase to achieve the asymptotic situation of the curve. Diplospora malaccensis was the most dominant species in the study area while Macaranga hosei was the most dominant species in Compartment 28 A (CL area) (Mardan et al., 2013). Although, Shorea kunstleri and Sapium baccatum were among the five top species with regard to the basal area production, they were not among the five top species in terms of IVI values because the number of those species was one and four tree ha-1, respectively. However, Mallotus kingii and Macaranga hosei were included in the list of the five top species in terms of IVI contribution. Results from UMFR and other study areas showed that the dominance of species is different from site to site. The dominance of species has been shown to depend on the quality of site and availability of the nutrient resources for plant establishment and plant growth (Kunwar and Sharma, 2004). Species importance value index and FIV computation of the study site showed that Diplospora malaccensis and Euphorbiaceae provided the highest level of those values (Table 8). However, Shorea curtisii ssp. curtisii which gave the highest level of IVI in the other logged-over and primary HDF was 42.9 and 32.6, respectively (Saiful, 2002; Kamziah et al., 2011). The family Dipterocarpaceae provided the highest level of FIV (Ghollasimood, 2011). Additionally, in the primary HDF in UMFR, the dipterocarps also gave the highest value of FIV (Saiful, 2002) (Table 8). However, in the logged-over HDF, Euphorbiaceae gave the highest FIV among all families because logging operations had targeted the large trees of 9 HDF during the period of timber harvesting. Hence, most of the dipterocarp trees were removed during that period. So, the pattern of primary HDF was not found in the study area due to the forest being logged-over. The notable point was that rich successional families such as Euphorbiaceae and Rubiaceae ranked in the first and second levels of that value, respectively (Okuda et al., 2003). Furthermore, among the 20 top species with regards to IVI, Shorea macroptera provided the second place of that value (Table 3). Our results showed that at the species level, in terms of dominant trees, the pattern of the logged-over HDF was to some extent similar to the undisturbed HDF while at the family level there was no similar pattern of the primary HDF. In the study site, successional species from the family Euphorbiaceae were found in all sampling plots. The positive signals of recovery of species composition were considered from regenerated HDF. However, long term research is required to confirm this. Also, the top niche species in the forest stand were indicated by the dominance-diversity curve. The top niche species were at the beginning of the curve while the other species were arranged in the sequence of their niche level and with moderate slope (Figure 2). The availability of appropriate niche and distribution of nutrient resources affected the relative species dominant (Kunwar and Sharma, 2004). The study site was generally high in tree diversity. However, changes were revealed when comparison of diversity index was made with other forests (Table 8 & 9). The Shannon-Weiner’s index of the primary HDF in UMFR was higher than that value of our study site which was 5.6 (Saiful et al., 2008) and 5.3, respectively. The Shannon-Weiner’s Index of HDF, UMFR, was lower than that value of other study sites (Table 8); the index of the study site was less than that value of Tekai Tembeling Forest Reserve (TTFR) (Kamziah et al., 2011) which was 5.3 and 7.0, respectively. However, Simpson and Smith-Wilson’s evenness indices of our area were higher than those values of TTFR. Out of 296 species, 121 species were classified under rare species (with ≤ two individuals). Additionally, data revealed that SL7/P3 was strongly disturbed during the past logging period (Fig. 6). However, overall diversity results showed that the secondary HDF was rich (Table 6 & 8) because the logged-over forest was in the gap phase of succession following logging operations. Van Gemerden et al. (2003) demonstrated that 834 species including 23% endemic were identified within Lower Guinea tropical rainforest of Cameroon. They concluded that regenerating forest can provide biological conservation as a buffer region around endangered zones. Our results showed high endemism in the study site (11.4% of total species was endemic). Endemic species shows biological uniqueness of an area (Peterson and Watson, 1998). The sampled area, species abundance and gap sizes in the forest might affect the biological diversity (Imai et al., 2013; Saiful & Latiff, 2014). Thus, we considered the fluxes in the Shannon-Weiner’s index when we compared 10 our results with other available data (Table 9). Since species diversity of UMFR was high, this secondary HDF can play a very crucial role in terms of biological conservation. Although the study site was strongly disturbed and with tracks of logging operations in the forest stand, the results showed that the logged-over forest can also play a very important role in environmental maintenance processes. The forest can provide multipurpose objectives such as biodiversity conservation, carbon storage, climate change mitigation, and soil and water resource preservation. Late and early successional species were recorded in the secondary HDF after logging (Davies et al., 2003; Lin et al., 2003). Late successional species such as Shorea parvifolia ssp. parvifolia (Hiromi et al., 2012), Hopea and some species including Intsia palembanica were recorded. The above mentioned individuals were in different stages of life form (seedling, sapling pole and mature tree). On the other hand, pioneer species were recorded in the study site. Hence, the positive signals of forest stand towards recovery were shown. The biological criteria are very useful tools to guide the forest management in conservation planning. Conservation of biological resources was presented by biological functions (Phua and Minowa, 2000). Consequently, conservation of logged HDF occurred in a proper way that can maintain the high value of biodiversity (Hamer et al., 2003; Cleary et al., 2005; Yamada et al., 2013). In the secondary HDF, it was observed that when the number of species in 1- ha was extremely large, the number of individuals of most of species was low. The numerous species were presented by small populations (one individual) include Shorea kunstleri, Canarium pseudosumatranum, Syzygium pustulatum, Serianthes grandiflora, Shorea pauciflora, Baccaurea sumatrana, Timonius wallichianus, Mezzettia parviflora and Beilschmiedia wallichiana. Similar results were reported by Fedorov (1966). Based on the results obtained, it can be presumed that self-pollination was more common than cross-pollination among the small population of trees. Thus, the automatic genetic improvement process of such small population will happen gradually (Fedorov, 1966). Furthermore, available published data showed the greater incidence of sun energy near the equator along with a resultant greater stability in biological productivity that might have been implicated in tropical speciation (Connell and Orias, 1964; Wright, 1983; Gentry, 1989). Thus, in the logged-over HDF, the gap formation resulting from logging, promoted greater sun light in the new environment for high level of diversity. Species richness estimation by rarefaction method was smaller than that value of Jacknife approach. According to rarefaction model, estimated species richness was close to the observed value of species richness (Figure 5). Based on Jacknife method, the predicted rate of species richness was higher than the observed rate of species richness (Table 5). Such results presented some uncertainties regarding the above mentioned methods. 11 Hence, further studies are required to improve and clarify the species richness estimation models (Figure 5 & Table 5). On the other hand Jacknife estimating model allowed us to include the rare species data in the calculation procedure and the majority of species (62.6%) was rare species (species with 1 or 2 individuals), hence the number of expected species was much higher (435.6) than observed species in the study site. CONCLUSION The supervised logged area of HDF at UMFR has high species diversity and species richness. High endemism is another feature of this area. The biological criteria are useful tools to guide the forest management in conservation planning. Monitoring studies will be important and provide future perspectives of responses of HDF towards supervised logging operations and climate change. . This is important for policy makers to consider the reduction process of biodiversity loss by forest degradation and deforestation. Also, they may consider the value of carbon-based payments for ecosystem services in tropical countries. ACKNOWLEDGEMENTS We would like to express our heartfelt appreciation to the late Pn. Latifah Zainal Abidin for helping us during the fieldwork. We also thank the Director of Kedah Forestry Department and Universiti Putra Malaysia (Grant t No. 9199757) for supporting this research. REFERENCES Akkharath, I., 2005. Effects of Forest Harvesting Operations on Suspended Sediment and Solute Loads in the Sungai Weng Experimental Watersheds, Kedah, Peninsular Malaysia. PhD Thesis, Faculty of Forestry. Universiti Putra Malaysia, Serdang, Malaysia, 292pp. (Unpublished) Bacaro, G., Rocchini, D., Ghisla, A., Marcantonio, M., Neteler, M. and Chiarucci, A., 2012. The spatial domain matters: Spatially constrained species rarefaction in a Free and Open Source environment. Ecol. Complex 12 : 63-69. Berry, N., Phillips, O., Lewis, S., Hill, J., Edwards, D., Tawatao, N., Ahmad, N., Magintan, D., Khen, C., Maryati, M., Ong, R. and Hamer, K., 2010. The high value of logged tropical forests: lessons from northern Borneo. Biodiversity Conserv. 19 : 985-997. Burgess, P., 1971. The effect of logging on hill dipterocarp forest. Malayan Nature Journal 24, 231-237. Chave, J., Andalo, C., Brown, S., Cairns, M.A., Chambers, J.Q., Eamus, D., Fölster, H., Fromard, F., Higuchi, N., Kira, T., Lescure, J.P., Nelson, B.W., Ogawa, H., Puig, H., Riéra, B. andYamakura, T., 2005. Tree allometry and 12 improved estimation of carbon stocks and balance in tropical forests. Oecologia 145 : 87-99. Chazdon, R.L., 2003. Tropical forest recovery: legacies of human impact and natural disturbances. Perspect Plant Ecol. 6 : 51-71. Cleary, D.R., Genner, M., Boyle, T.B., Setyawati, T., Angraeti, C. and Menken, S.J., 2005. Associations of Bird Species Richness and Community Composition with Local and Landscape-scale Environmental Factors in Borneo. Landscape Ecol. 20 : 989-1001. Clifford, H.T.,Stephenson, W., 1975. An introduction to numerical classification. Elsevier. Connell, J.H. and Orias, E., 1964. The ecological regulation of species diversity. American Naturalist 98: 399-414. Curtis, J.T. and McIntosh, R.P., 1951. An Upland Forest Continuum in the PrairieForest Border Region of Wisconsin. Ecology 32 : 476-496. Davies, S.J., Noor, N.S.M., LaFrankie, J.V. and Ashton, P.S., 2003. The trees of Pasoh Forest: stand structure and floristic composition of the 50-ha forest research plot. In: T. Okuda, N. manokaran, Y. Matsumo, K. Niiyama (Eds.), Pasoh. Springer, pp. 35-50. Ellenberg, D. and Mueller-Dombois, D., 1974. Aims and methods of vegetation ecology. Wiley New York, NY, USA. Faridah-Hanum, I., Miskon Simon and Awang Noor Abdul Ghani. 1999. Tree Species Diversity and Economic Value of a Watershed Forest in Ulu Muda Forest Reserve, Kedah. Pertanika Journal Tropical Agricultural Science 22(1): 63 – 68. Fedorov, A.A., 1966. The Structure of the Tropical Rain Forest and Speciation in the Humid Tropics. J. Ecol. 54 : 1-11. Fisher, R.A., Corbet, A.S. and Williams, C.B., 1943. The relation between the number of species and the number of individuals in a random sample of an animal population. The J. Anim. Ecol. 12(1): 42-58. Gentry, A.H., 1989. Speciation in tropical forests. In: Holm-Nielsen, L.B., Nielsen, I.C., Balslev, H. (Eds.), Tropical Forests. Academic Press, London, pp. 113-134. Ghollasimood, S., 2011. Floristic Composition, Diversity and Economic Valuation of a Coastal Hill Forest in Pulau Pangkor, Malaysia. Faculty of Forestry Ph.D, 254pp (Unpublished). Grace, J., 2004. Understanding and managing the global carbon cycle. J. Ecol. 92 : 189-202. Hamer, K.C., Hill, J.K., Benedick, S., Mustaffa, N., Sherratt, T.N. and M. Maryati. 2003. Ecology of butterflies in natural and selectively logged forests of northern Borneo: the importance of habitat heterogeneity. J. Appl. Ecol. 40 : 150-162. Hiromi, T., Ichie, T., Kenzo, T. and Ninomiya, I., 2012. Interspecific variation in leaf water use associated with drought tolerance in four emergent dipterocarp species of a tropical rain forest in Borneo. J. For. Res. 17 : 369-377. Imai, N., Seino, T., Aiba, S.-I., Takyu, M., Titin, J. and Kitayama, K., 2013. Management effects on tree species diversity and dipterocarp regeneration. In Co-benefits of Sustainable Forestry. Springer, Japan, pp. 41-61. 13 Kamziah, K.A., Eswani, N., Nazre, M., Awang Noor, A. and Ali, M., 2011. Tree species diversity of logged over forest at Tekai Tembeling Forest Reserve, Jerantut, Pahang, Malaysia. Malaysian Forester 74 : 173-181. Kimmins, J.P., 2004. Forest ecology: a foundation for sustainable management. Prentice-Hall Inc. Kochummen, K.M., 1978. Symplocaceae. In: Whitmore, T.C. (Ed.), Tree flora of Malaya: a manual for foresters. Longman, Kuala Lumpur. Krebs, C.J., 1999. Ecological methodology. Benjamin/Cummings Menlo Park, California. Kunwar, R.M. and Sharma, S.P., 2004. Quantitative analysis of tree species in two community forests of Dolpa district, mid-west Nepal. Himalayan J. Sci. 2 : 23-28. Lim, J.S., 1991. Soil-Landscape Relationships in Kedah- A Study in Soil Genesis and Classification. PhD Thesis, Faculty of Agriculture. Universiti Pertanian Malaysia, Serdang, Malaysia, 447 pp. (Unpublished) Lin, T.-C., Hamburg, S.P., Hsia, Y.-J., Lin, T.-T., King, H.-B., Wang, L.-J. and Lin, K.-C., 2003. Influence of typhoon disturbances on the understory light regime and stand dynamics of a subtropical rain forest in northeastern Taiwan. J. For. Res. 8 : 139-145. Lugo, A. and Brown, S., 1986. Steady state terrestrial ecosystems and the global carbon cycle. Vegetatio 68 : 83-90. Mardan, M.N., Hakeem, K.R., Faridah-Hanum, I. and Saari, N.S., 2013. Tree Species Composition and Diversity in One Ha Forest, Ulu Muda Forest Reserve, Kedah. Sains Malaysiana 42 : 1409-1424. Mori, S.A., Boom, B.M., Carvalino, A.M.D. and Talmon, S.D.S., 1983. Ecological Importance of Myrtaceae in an Eastern Brazilian Wet Forest. Biotropica 15 : 68-70. Ng, F.S., Low, CM. and Sanah, Mat Asri Ngah., 1990. Endemic Trees of the Malay Peninsula. Forest Research Institute Malaysia, Kuala Lumpur. 118pp. Ng, F.S.P., 1989. Elaeocarpaceae. In: F.S.P. Ng, D.P.O. (Ed.), Tree flora of Malaya 4 : a manual for foresters. Longman, Kuala Lumpur, Malaysia, pp. 82-98. Okuda, T., Suzuki, M., Adachi, N., Quah, E.S., Hussein, N.A. and Manokaran, N., 2003. Effect of selective logging on canopy and stand structure and tree species composition in a lowland dipterocarp forest in peninsular Malaysia. For. Ecol. Manage. 175 : 297-320. Peterson, A.T. and Watson, D.M., 1998. Problems with areal definitions of endemism: the effects of spatial scaling. Diversity and Distributions 4 : 189-194. Phua, M.-H. and Minowa, M., 2000. Evaluation of environmental functions of tropical forest in Kinabalu Park, Sabah, Malaysia using GIS and remote sensing techniques: implications to forest conservation planning. J. For. Res. 5 : 123-131. Pielou, E.C., 1966. Species-diversity and pattern-diversity in the study of ecological succession. J Theor Biol 10, 370-383. Pielou, E.C., 1975. Ecological diversity. Wiley New York. Saiful, I., 2002. Effects of selective logging on tree species diversity, stand structure and physical environment of tropical hill dipterocarp forest of 14 Peninsular Malaysia. PhD thesis, faculty of Life Sciences, University Kebangsaan Malaysia, Malaysia, Bangi. 278 pp. (Unpublished) Saiful, I., Faridah-Hanum, I., Kamaruzaman, J. and Latiff, A., 2008. Floristic diversity, composition and richness in relation to topography of a hill dipterocarp forest in Malaysia. In, 3th IASME/WSBAS Int. Conf. on Energy & Environment, pp. 23-25. Saiful, I. and Latiff, A., 2014. Effects of selective logging on tree species composition, richness and diversity in a hill dipterocarp forest in Malaysia. Journal of Tropical Forest Science 26 : 188-202. Seaby, R. and Henderson, P., 2006. Species diversity and richness version 4. Pisces Conservation Ltd., Lymington, England. Simpson, E.H., 1949. Measurement of diversity. Nature 163 : 688-688. Sist, P., Dykstra, D. and Fimbel, R., 1998. Reduced-impact logging guidelines for lowland and hill dipterocarp forests in Indonesia. CIFOR, Indonesia. Smith, B. and Wilson, J.B., 1996. A Consumer's Guide to Evenness Indices. Oikos 76, 70-82. Symington, C.F., Ashton, P.S., Appanah, S. and Barlow, H.S., 2004. Foresters' manual of dipterocarps, Second edition. Forest Research Institute Malaysia, Malaysia. Turner, I., 1995. A catalogue of the vascular plants of Malaya. The Gardens Bulletin Singapore. 47 (1 & 2): 1-757. Turner, M.G., Baker, W.L., Peterson, C.J. and Peet, R.K., 1998. Factors influencing succession: lessons from large, infrequent natural disturbances. Ecosystems 1 : 511-523. Valappil, N. and Swarupanandan, K., 1996. Regeneration dynamics and sylvigenesis in the moist deciduous forests of southwest India. New forest 11 : 185-205. Van Gemerden, B.S., Shu, G.N. and Olff, H., 2003. Recovery of conservation values in Central African rain forest after logging and shifting cultivation. Biodivers. Conserv. 12 : 1553-1570. Whitmore, T.C., 1972. Tree Flora of Malaya 1 : A Manual for Foresters. Longman, Kuala Lumpur. Whitmore, T.C., 1973. Euphorbiaceae. In: Whitmore, T.C. Tree Flora of Malaysia 2 : A Manual for Foresters. Longman, Kuala Lumpur, pp. 34-137. Whitmore, T.C. and Burnham, C.P., 1984. Tropical Rain Forests of the Far East. Oxford University Press,. Wright, D.H., 1983. Species-energy theory: an extension of species-area theory. Oikos, 496-506. Yamada, T., Hosaka, T., Okuda, T. and Kassim, A.R., 2013. Effects of 50 years of selective logging on demography of trees in a Malaysian lowland forest. For. Ecol. Manage. 310 : 531-538. 15