The Potential of Dipterocarpaceae in the Karst of Sangkulirang Mangkalihat Rifani1 Matius Paulus1 Hastaniah1 Sutedjo1 Raharjo Ari Swasono1 Rita Diana1,*

Advances in Biological Sciences Research, volume 11 Proceedings of the Joint Symposium on Tropical Studies (JSTS-19)

1 Faculty of Forestry, Mulawarman University, Kampus Gn. Kelua Jl. Ki Hajar Dewantar, Samarinda, Indonesia *Corresponding author. Email: [email protected]

ABSTRACT The Dipterocarpaceae are very dominant in the Kalimantan forest, which has an important role in economic and conservation aspects. The aim of this research is to determine the potential of Dipterocarpaceae at karst Sangkulirang – Mangkalihat in Berau and Kutai Timur Regency. The research is about two months in six locations. The plotting method is using the purposive sampling method, and 15 plots were made at each location. The number of Dipterocarpaceae species found is 31 species comprising 174 individuals in 7 genera, such as Anisoptera spp., Dipterocarpus spp., Dryobalanops spp., Hopea spp., Parashorea spp., Shorea spp., and Vatica spp. Genera that was not found, i.e., Cotylelobium spp. and Upuna spp. The number of potential Dipterocarpaceae tree species found is 95 individuals (105 individuals per hectare) with a basal area of 67.59 m2 per hectare and 129.65 m3 volume per hectare. The number of sapling species found is 52 individuals (253 individuals per hectare) and 28 individuals (3111 individuals per hectare).

Keywords: Dipterocarpaceae, potential, Karst Sangkulirang-Mangkalihat

1. INTRODUCTION 2. RESEARCH METHODS Limestone hill forest ecosystem is one of the unique The research was carried out for two months in 6 lowland rain forest ecosystems because it has locations, i.e., Biatan Ulu, Suaran, Lubang Kelatak, morphological conditions and rock natures different Biduk-biduk (Teluk Sulaiman), Tondoyan, and Gergaji. from the other ecosystem types [1]. Limestone hill The plotting method was done using the purposive forests generally have few plants and species. sampling method, with a plot size of 10×10 m for trees, Dipterocarpaceae are the leading timber producer trees 5×5 m for a sapling, and 1×1 m for seedlings. Fifteen of tropical rain forests in western Indonesia, Malaysia, plots were made at each location. The data recorded Brunei, and the Philippines and spread eastward to Irian were for the tree (species name, diameter, height, Jaya and Papua New Guinea. The timber industry found number of individuals), for the sapling (species name, that most genera from the Dipterocarpaceae family were number of individuals), and the seedling (species name, difficult to identify, especially in Borneo Island, since number of individuals). they have a high number of species [2]. In Borneo Island, there are nine genera of the Dipterocarpaceae family. Of 268 species and 27 subspecies were recorded. Of 113 species, among them are endemic to the island of Borneo. The nine genera of the Dipterocarpaceae family found on Borneo's island are Anisoptera, Dipterocarpus, Dryobalanops, Cotylelobium, Hopea, Parashorea, Shorea, Upuna, and Vatica [2].

Advances in Biological Sciences Research, volume 11

Figure 1 The scheme of making plot

3. RESULT AND DISCUSSION forms an inverted J-like curve where individuals of each diameter class decrease with the size of the tree 3.1. Potential of the Family Dipterocarpaceae diameter. These changes are caused by the speed of growth and variations in growing space needed in tree There were 31 species of 7 genera of the growth so that competition and natural selection occur, Dipterocarpaceae in karst Sangkulirang Mangkalihat, both among similar and different species. This is what i.e., Anisoptera spp., Dipterocarpus spp., Dryobalanops causes changes in the distribution of trees in forest spp., Hopea spp., Parashorea spp., Vatica spp., Shorea stands. The above statement is supported [3], which spp. The genus of Cotylelobium spp. and Upuna spp. states that in a non-lifetime stand, the frequency were not found. The number of Dipterocarpaceae distribution of the number according to its diameter potential stands is 174 individuals subdivided into class will form an inverse J-curve. several levels, including trees, saplings, and seedlings. There are 95 individuals (105 N/Ha) with a basal area of 3.3.2. Vertical Structure 67.59 per hectare and a volume of 129.65 m3 per hectare for tree level. The number of sapling levels is 51 Stratification can be determined based on the height individuals (253 N/Ha) and 28 individuals for seedlings of the vegetation canopy, [4] divided stratification into (3,111 N/Ha). It can be seen in more detail in Figure 2. three strata, i.e., stratum A (height > 30 m), stratum B (height 20-30 m), and stratum C (height 4-20 m). In 6 locations, Biatan Ulu and Suaran have a quite Stratification in forest stands occurs due to differences high potential because these two areas are still in the in age and competition between one particular type and primary forest category because they are still in good another, forming a vertical structure [5]. conditions and lack community activities. Besides, Lubang Kelatak and Biduk-biduk (Teluk Sulaiman) are The vertical structure of Dipterocarpaceae stands categorized as old secondary forests; several illegal (diameter 10 cm and over) has three strata (A, B, and logging activities by the surrounding community might C), where strata with the height of 4-20 m always disturb the forest. The Tondoyan and Gergaji have the dominate each location, especially in primary forest low potential of the Dipterocarpaceae family. According areas (Biatan Ulu and Suaran), except Biduk-biduk to residents during the great fires in 1982 and 1998, (Teluk Sulaiman), which is dominated by the strata with these two regions were also burned at the time, which the height of 20-30 m. This shows the regeneration of made the Dipterocarpaceae family's development Dipterocarpaceae species is still stable and is a process stunted. characteristic of dipterocarp forest which continuously varies in the age of vegetation. The difference in a 3.3. Dipterocarpaceae Stand Structure stratum is due to competition between plants and the tolerance of tree species to the radiation, of the age of forest stands, in the formation of a region's strata [6]. 3.3.1. Horizontal Structure The larger the diameter and height of the Tree diameter distribution is dominated by trees with Dipterocarpaceae, the fewer individuals. Naturally, this diameters between 10-20 cm, where the number competition reduces the number of individuals who decreases when it reaches a larger diameter. When survive at each diameter class level [7]. drawn from the graph above, it can be seen that the horizontal structure of forest stands in the six study sites

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100 95 80 51 60 42 31 28 40 18 19 10 10 12 20 5 3 7 4 1 3 6 0 2 1 0

0 Total Total Individual

location research Pohon Pancang Semai

Figure 2 Potential of Stand

25 23

20 14 15

10 6 6 7

Total Total Individual 4 4 5 2 2 3 3 2 2 2 2 2 3 1 1 1 1 0 1 0 1 0 0 0 1 0 0 0 1 0 0 0 0 10-20 20-30 30-40 40-50 50-60 >60 Distribution Diameter

Biatan Ulu Suaran Lobang Kelatak Biduk-biduk - Teluk Sulaiman Tondoyan Gergaji

Figure 3 Picture of Tree Level Diameter Distribution Chart

3.4. Domination of Dipterocarpaceae Species contained 12 species of Dipterocarpaceae was identified in the study location where three species with 3.4.1. The presence of Dipterocarpaceae Trees individuals and the frequency of presence were dominant, That is Shorea laevis Ridl., Shorea guiso in the Six Locations (Blanco) BL., Vatica rassak Blume. For more details, From the results of the field data collection of tree- see Figure 6. level Dipterocarpaceae analysis in six locations, there are 27 species of Dipterocarpaceae family identified 3.4.3. The Presence of Dipterocarpaceae where three species with individuals and the dominant Seedling in All Six Locations frequency of presence were observed, i.e., Vatica rassak Blume, Shorea guiso (Blanco) BL., and Vatica odorata From the results of field data collection, the sapling (Griff.) Symington. More details can be seen in Figure level of Dipterocarpaceae stands at the study site 5. contained seven species of Dipterocarpaceae was identified in the study location. Where three species 3.4.2. The Presence of Dipterocarpaceae Sapling with individuals and the frequency of presence were dominant, that is Vatica rassak Blume, Shorea guiso in the Six Locations (Blanco) BL., Shorea laevis Ridl. For more details, see From the results of field data collection, the sapling Figure 7. level of Dipterocarpaceae stands at the study site

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60 50 50

40 35

30 21 21 18 20 Total Total Individual 8 9 10 3 4 3 5 2 2 1 1 1 1 1 2 0 0 0 Biatan Ulu Lobang Kelatak Tondoyan Total

Location research C (4-20) B (20-30) A (>30)

Figure 4 Chart of Stand Distribution

Vatica rassak Blume 1 22 1 1 2 7 1 1 8 Vatica odorata (Griff.) Symington 4 2 6 1 4 1 6 Hopea rudiformis P.S.Ashton 4 2 6 3 1 1 5 Dipterocarpus tempehes Sloot. 2 3 5 4 4 Shorea sp6. 3 3 2 1 3 Parashorea malaanonan Blanco.Merr. 3 3 1 2 3 Vatica sp1. 1 1 2 1 1 2 Shorea sp7 2 2 2 2

Scientific Name Scientific Anisoptera megistocarpa Slooten 2 2 1 1 Shorea sp5. 1 1 1 1 Shorea sp3. 1 1 1 1 Shorea ovalis (Korth.) Bl. 1 1 1 1 Shorea fallax Meijer 1 1 1 1 Hopea nervosa King 1 1 0 5 10 15 20 25 30 Total Individual Suaran 34 Individu 14 spesies Biatan Ulu 42 Individu 10 Spesies Lobang Kelatak 10 Individu 9 spesies Biduk-biduk - Teluk Sulaiman 7 Individu 6 spesies Tondoyan 3 Individu 2 spesies

Figure 5. The Presence of Dipterocarpaceae in the Six Locations The three images above can be seen species with are always dominant at an altitude of 500 meters above individuals. Their frequency of presence is dominant at sea level with limestone hill forest types. From the 6 the level of trees, saplings, and seedlings, i.e., Vatica study sites both at the tree level, saplings, and seedlings, rassak Blume and Shorea guiso (Blanco) BL. This is Suaran and Biatan Ulu's location is always dominant in influenced by the limestone hill forest types' ecological the presence of individuals and species from other suitability and the dominant type of individual presence research locations. in lowland tropical rainforests under 300 m asl [8]. According to [9], the genus Shorea, Vatica, and Hopea

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Figure 6 The Presence of Dipterocarpaceae Trees in the Six Locations

Vatica rassak Blume 1 9 1 1 1 Shorea guiso (Blanco) Bl. 6 1 7 Shorea laevis Ridl. 1 2 2 5 Shorea pauciflora King 2 2

Hopea rudiformis… 1 1

Hopea dryobalanoides Miq. 1 1 Scientific Name Scientific Dipterocarpus caudiferus… 1 1 0 2 4 6 8 10 12 Total Individual Suaran 10 Individu 5 Spesies Biatan Ulu 5 Individu 3 Spesies Lobang Kelatak 12 Individu 3 Spesies Biduk-biduk - Teluk Sulaiman 1 Individu 1 Spesies Tondoyan 0 Individu 0 Spesies Gergaji 0 Individu 0 Spesies

Figure 7 The Presence of Dipterocarpaceae seedlings in the Six Locations

4. CONCLUSION hill forest is Vatica rassak Blume. and Shorea guiso (Blanco) BL., because both species always present in Biatan Ulu and Suaran cultures, which are primary every condition of the forest that is primary and forests with abundant individual Dipterocarpaceae, secondary limestone hills. presences the number of individual decreases with increasing diameter and height of the stand. The type that matches the ecological conditions of the limestone

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ACKNOWLEDGMENT

The author would like to thank all those who have helped in the research advance Lasmito, Zulkifli, Atma Wahyu Wiyanata, Dwi Putri Ramadhani, Maldi Nurachman, Muhammad Fajar Tegar Wahyudi, Jeka Risky Febrian, Febrian Sara TFCA Kalimantan, and Faculty of Geography, Gadjah Mada University.

REFERENCES

[1] Whitten et al., Ekologi Sulawesi, Gadjah Mada University Press, Yogyakarta, 1987. [2] Newman dkk, Pedoman Identifikasi Pohon-Pohon Dipterocarpaceae Pulau Kalimantan, Prosea Indonesia, Bogor, 1999. [3] Daniel et al., Prinsip-prinsip Silvikultur, Terjemahan, Edisi Ke-2, Terjemahan, Gadjah Mada University Press, Yogyakarta, 1987. [4] I. Soerianegara, A. Indrawan, Ekologi hutan, Fakultas Kehutanan Institut Pertanian Bogor, Bogor, 1988. [5] Tri Atmoko dkk, Structure and Distribution of Dipterocarpaceae Trees in Merapit Seed Stand, Central Kalimantan, Balai Penelitian Teknologi Konservasi Sumber Daya Alam, Samboja, Kalimantan Timur, 2011. [6] Indriyanto, Ekologi Hutan, PT Bumi Aksara, Jakarta, 2008. [7] S. Susanti, Komposisi Jenis dan Struktur Tegakan Regenerasi alami di Hutan Pendidikan Gunung Walet, Sukabumi, Bachelor of Forestry, Department of Silvikultur, Faculty of Forestry, Institut Pertanian Bogor, Bogor, 2014. [8] Asthon, Tree Flora of Sabah and Sarawak, Arnold Arboretum, Harvard University Herbaria, Cambridge, Massachusetts, U.S.A. and Royal Botanic Gardens, Kew, England, UK, 1982. [9] Purwaningsih, Ecological distribution of Dipterocarpaceae species in Indonesia, Pusat Penelitian Biologi-LIPI, Bogor, 2004.

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