Insular

The insular component of South-East Asia consists of archipelagoes that rim the continent between the Indian and Pacific Oceans. The geographical alignment is determined by major structural arcs traversing the region. The islands are dominated by rugged mountain backbones, many of which have volcanic cones. Those on the west, such as Sumatra, Borneo, and Java, that rest on the continental shelf have fairly extensive coastal lowlands fringed by shallow seas. Eastwards, the islands rise abruptly from deep seas like the isolated peaks of submerged mountain ranges and, in many cases, have virtually no coastal plain. The description of the mountains of insular South-East Asia is given in three groups: Borneo, The Philippines, and Indonesia.

South-East Asia is a region in which the land divides but the sea unites (Fisher 1964, p 662). This is seen in The Philippines as a country of 7,000 islands and in Indonesia, a country of of 3,000 islands, while the singular block of Borneo is shared by Indonesia, Malaysia, and Brunei. Borneo is not only the largest island in the region, it also has the highest peak (Gunung Kinabalu - 4,094m) outside the continental interior (Box 3). Borneo's highland backbone is aligned like a trident pointing to the south-west. It commences in Sabah with Crocker Range in the extreme north. The central range, Pegunungan Iran, is a prominent water divide along the Indonesian-Malaysian border. Around Bukit Batubrok (2,240m) it bifurcates into three ranges. One continues south-west along Muller Range towards Schwaner Range. The western branch, Kapus Hulu, defines the boundary between Indonesia and Malaysia. The eastern branch, the Meratus Range is the lowest of the three. The main relief pattern is determined by the axes of Tertiary folding running in a series of parallel curves. Although parts of the northern heights, including Kinabalu Peak, are granitic, most rock formations are sandstone and limestone. These highlands have dense equatorial rain forests with successions of montane and even alpine types on the highest elevations with over 4,000 plant species. The various indigenous groups include the Dusun, Kadazan and Murut in Sabah; the Iban and Penan in Sarawak; and the Barito and Maloh in Kalimantan.The islands of The Philippines straddle a zone of Tertiary/Quaternary folding of active vulcanism trending north-south between deep sea basins. Nearly all have rugged interior highlands and in combination resemble the upper portions of submarine mountain ranges. Superior elevations are, however, confined to the larger islands, Luzon and Mindanao respectively, in the extreme north and south. Mount Pulug (2,929m) in Luzon in the north and Mount Apo (2,954m) in Mindanao in the south are in the same elevation range. Luzon includes two parallel ranges with the higher Cordillera Central as the spine and the Sierra Madre along the east coast. The dominant rocks are Tertiary sedimentaries with some exposures of ancient basement complex in mountain cores. Zambales, across the Lingayen Gulf, is a volcanic range that receives a lot of rain and has dense forests. The highlands around Banaue are famous for elaborate field terraces. However, this wet rice culture of the Bontoc and Ifugao is an exception amid a vast area of shifting cultivation (kaingin) by other tribes and the still primitive Negrito of the Sierra Madre and Zambales.

The southern island of Mindanao has, as in Luzon, two north-south trending ranges. Here also, the western range forms the core of the island whereas the eastern one is mainly littoral. The former traverses the entire island as a distinct watershed between the Agusan Valley to the east and the Mindanao Basin to the west. A western spur, the Katanglad Mountains, has many peaks above 2,800 m, but the highest one, Mount Apo, on the main range, lies further south. Rainfall on the highlands is about 800m lower than on the east coast but occurs all the year round and supports dense vegetation. The uplands are also used for vegetable production under a fallow system with an average re-cultivation period of four years. The highland tribals are mostly Moro, and they are sandwiched between adherents of Islam in the west and Christianity in the east.

Indonesia consists of numerous large and small islands spread over a vast area. The major structural alignment is east-west, dictated by two parallel ranges of Tertiary/ Quarternary folding. In the north-east, the axes of the fold turn north towards The Philippines to which they are geologically linked. The inner of the two major east-west folds indeed forms the spine of the long island chain through a series of volcanic cones from Sumatra to Timor. The description of the mountains of Indonesia is given in five sections: (1) Sumatra, (2) Java, (3) Lesser Sundas, (4) Sulawesi, and (5) Moluccas.

Sumatra Island is marked by highlands along its entire length of over 1,700 km. Alhough it is called Bukit Barisan (The Mountain Range), it consists of two or more parallel ridges separated by structural troughs adjacent to numerous extinct and active volcanoes. In the north, Pulau Samosar is an island within the crater of Toba Lake. The range runs close to the western side of the island and has a precipitous slope facing the Indian Ocean. The main sections are the Aceh Range in the north, the lava and tuff plateau of Batak, the ridge and basin of Padang highlands, and finally the Benkulen Ridge to the south. Some peaks approach 3,000m in elevation, the highest being Kerinci (3,805m) in the Padang highlands. These highlands receive heavy rain from the south-west monsoon. Except for the intermontane Batak Plateau with savanna vegetation, most of the highlands have dense tropical rain forest. The indigenous people are the Batak and Gajo in the north, the Menangkabau in Padang, and the Lamponger in the south. Shifting cultivation, or ladang, is common in these highlands.

The slender island of Java, extending nearly 1,000km east-west, is dominated by a chain of volcanic cones. Of these 17 are still active and 14 exceed 3,000m in elevation, the highest being Gunung Slamet (3,428m). In the west, a clus ter of peaks forms the rugged relief of the Priangan Plateau. In central and eastern Java, the peaks are more spaced and are separated with lowlands. The central range is composed mainly of Tertiary basalts and andesites and Quaternary volcanics. As in the case of Sumatra, the southern slope facing the Indian Ocean is steep. Overall, the soils derived from ejected lava and ash combined with abundant rainfall make the base of these highlands fertile, and it is an area where the rural population is extremely dense.

© Madhukar Rana

17. Traditional Bali Dance, Indonesia

Lesser Sundas is composed of small islands aligned east-west between Bali and Timor. In structure and physiography they are an eastern extension of Java, but on a smaller scale. Most of the island cores are volcanic peaks that rise abruptly from the sea. These high points reach 3,142m in Bali, 3,726m in Lombok, 2,850m in Sumbawa, 2,400m in Flores, and 2,427m in Timor Island. The area has scrub-like vegetation, due to its long dry season. The population is basically Malay who engage in wet-rice cultivation. However, the Balinese stand out as a relict of the Hindu-Javanese culture amidst an Islamic realm (Plate 17).

The spread-eagled island of Sulawesi lies north of Lesser Sundas. Its distinctive layout and relief are related to a number of factors: convergence of several axes of Tertiary folding and extensive uplift, faulting, and subsidence. Therefore, it is distinguished by high relief and wide occurrence of lakes with a maze of rift valleys. The highest point, Rantekombola (3,455m), is located south of the central axis from where ranges diverge to the extremities of the peninsula. Most of the vegetation is tropical rain forest. The highland people, mostly animist Toradja in various tribes, practice shifting cultivation. Those engaged in wet- rice cultivation are Muslim Buginese and Christian Minahasan.

The Moluccas form a group of small islands on the extreme east of South-East Asia. These include Halmahera in the north, Obi in the centre, and Buru and Seram in the south. They represent a collision of north-south and east- west aligned structural axes. The uplands in Halmahera in the north are volcanic. The elevation rises towards the south, culminating on Gunung Binaiya (3,119m) in Seram. The highland people are of Melanesoid, Australoid, and Negrito origins, and their occupations range from shifting cultivation to hunting and fishing.

Box 3
Climbing Mount Kinabalu

The Kinabalu Park in Sabah is crowned by Mount Kinabalu (4,101m) (Plate 16), the highest peak in South-East Asia. The Park covers an area of 754 sq. km. With probably the richest flora in the world. These include 1,500 species of orchids, 80 of figs, 60 of oak/chestnut, and 26 rhododendron varieties. The Park headquarters at 1,524m is about two hours drive from Kota Kinabalu. The summit lies nine kilometres north of Park headquarters, involving an ascent of 2,577 metres. The climb can be accomplished in two to three days. It is, however, an entirely different matter for those with proven stamina. Passing the welcome gate (`Selamat Mendaki') in October 1994, I came across the following bill-board.

International Climbathon, 1993

Those from Nepal were Gurkha soldiers serving in Hong Kong. In the female category, the top three places were taken by local Malays, the first covering in 3 hours, 28 minutes and 16 seconds.

For an average climber, there is no need to rush. It can be a journey to discover the rich variety of flora and fauna. The climb starts beside the Power Station (1829m), which lies above the tropical Dipterocarp vegetarian zone. Then the path ascends under a temperate forest of oak, chestnut, myrtle laurel, and rhododendron.

© Author

16.Mt. Kinabalu, Malayasia. Mount Kinabalu (4,101m) is the highest peak on the vast stretch between the continental Hengduan Ranges and New Guinea in the Pacific. The granite massifs are shaped by glacial scouring and frost shattering. It is considered sacred _ as the resting place of departed Kadazan/Dusun people.

Around 1,900m begins the cloud forest zone of gnarled tree-trunks festooned with moss, epiphytic ferns, and orchids. Beyond 2,100m, appear Pitcher plants of various species. Higher up, Schima breviforme with white flowers and Vaccinium with crimson leaves are notable. There are six rest places between the climb entrance (Power Station) and Panar Laban (3,353m). Panar Laban (`Place of Sacrifice') is 1,500 meters higher from the commencement of the trek at the Power Station, and has lodging facilities. Beyond Panar Laban, vegetation becomes stunted and scarce. Instead, bare rock faces of granite loom large. A narrow gully and then a rocky traverse leads to Sayat-Sayat (3,810m), the highest hut on the mountain. Sayat-Sayat is the native name for the Leptospermum bush, abundant around here.

The final ascent is across the summit plateau of wide slabs of granite assisted with a rope line. Most begin their climb in the very early morning from Panar Laban or Sayat-Sayat to be in time to see the sunrise from the summit. The highest summit, Low's Peak, provides excellent views all around. The place can be windy with mist swirling around.

Source: Harka Gurung. ADIPA Newsletter (Kuala Lumpur), August, 1995, pp. 1,23 & 24.