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$Pretitle{}
$Title{Indonesia
Chapter 2A.   The Society and Its Environment}
$Subtitle{}
$Author{Riga Adiwoso-Suprapto}
$Affiliation{HQ, Department of the Army}
$Subject{islands
java
sea
sumatra
indonesia
island
indonesian
area
sulawesi
western
see
pictures
see
figures
}
$Date{1982}
$Log{}
Title:       Indonesia
Book:        Indonesia, A Country Study
Author:      Riga Adiwoso-Suprapto
Affiliation: HQ, Department of the Army
Date:        1982

Chapter 2A.   The Society and Its Environment

     Indonesians call their country "Our Lands and Waters" (Tanah Air Kita),
an appropriate name for a country of islands whose water surface area is
greater than its land area. The sea is an important part of Indonesian life,
providing the main share of protein in the daily diet and functioning both as
a pathway for communication and as a cultural barrier. The difficulty of
reaching the interior of many islands has served to foster social, cultural,
and economic isolation among the approximately 300 ethnic groups. The
archipelagic nature of the country-incorporating some 13,000 islands-has
provided naturally discrete regions where ethnic groups have been able to
develop a cultural core of their own, with varying degrees of input from
outside.

     Indonesia is known to be a meeting ground of cultural forces. Its
history must be interpreted in terms of the importation and adaptation of
ideas and philosophies from India, the Islamic world, China, and the West. The
complexity of modern Indonesian society can only be explained, however, in the
light of both indigenous foundations and foreign influences. Foreign
influences figured significantly in the shaping of Indonesian society, but to
seek to explain its evolution solely in terms of alien inspiration would be
wholly misleading. Belief in the underlying importance of harmony and
consensus and the value of maintaining man and nature in equilibrium have
enabled Indonesia to absorb outside influences without being absorbed itself.

     In the 1980s modern Indonesian society was still in transition. It had
absorbed those Western influences it felt were necessary to gain international
recognition and promote economic development; at the same time the government
was seeking to increase national consciousness and pride. But in its attempt,
the government had to confront a multiplicity of diverse ethnic traditions.
Those diverse traditions reflected a complex mosaic of self-conscious ethnic
groups distinguished by custom, ecological adaptation, religious belief and
practices, language and social organization.

     Although the government strives for the nationalist ideal of a homogenous
society and encourages the people to regard themselves as Indonesians,
feelings of ethnic distinctiveness remain strong; at the same time,
identification with an ethnic group is not felt to be incompatible with
loyalty to the Indonesian nation. The foundation for national consciousness
was laid through the experience of Dutch colonization and Japanese occupation
shared by the various ethnic groups.

     The majority of Indonesians are rural inhabitants, attached to the
traditional cultural values of the ethnic groups to which they belong. The
rural inhabitants present themselves as an undifferentiated group, solidly
loyal to each other; nonetheless, the social organization has continued to be
based on a centuries-old division between gentry and commoners. The
introduction of modern technological knowledge into the rural areas has
caused rapid change in social values, often producing a materialistic outlook
incompatible with a traditional orientation.

     In the 1980s social organization in the cities and towns was based on two
variables: the degree to which an urban inhabitant maintained an ethnic
heritage and the amount of Western influence exhibited in a life-style. At the
apex of urban society was a tiny segment of the elite stratum that preserved
only a minimal amount of its ethnic legacy, being oriented instead toward a
metropolitan cultural tradition modeled on that of the West. An important
characteristic of this metropolitan culture was its use of the Indonesian
language in literature, popular music, films, and everyday communication. The
rest of the elite stratum was also oriented toward metropolitan culture but
exhibited a larger degree of adherence to its ethnic heritage. Below the elite
stratum were middle and lower classes, whose members were mostly bicultural;
they retained features of their ethnic culture for certain domains in their
life, while adopting to metropolitan culture in others.

     Upward mobility in urban society was attained through a combination of
family connections, education, military background, and personal experience.
Yet, for many in the middle and lower classes, such mobility was hindered by
the steady increase in the labor force, which had resulted in severe
unemployment and underemployment problems. To alleviate the impact of these
conditions in both urban and rural areas, the government emphasized employment
expansion through agricultural development programs and efforts to promote
industrial growth.

     Another major problem was the uneven distribution of the population.
Java, comprising only 6.9 percent of the total land area, had almost 65
percent of the population. In the early 1980s the government was encouraging
voluntary migration to other, less densely populated islands, under what was
officially termed transmigration. The development plan Repelita III allocated
some Rp 109 trillion (for the value of the rupiah-see Glossary) to move
approximately 2.5 million people. The goal was highly optimistic, given the
difficulties in establishing basic community infrastructure and roads, coupled
with the harshness of the terrain in resettlement areas.

     In the urban centers the deep cleavage between the elite and the poorest
groups in society gave rise to such problems as prostitution, crime and
violence, and juvenile delinquency. Many rural inhabitants moved to the cities
with the hope of attaining a better life or earning enough money to send their
extended families in the countryside. In the cities they often failed to find
adequate employment, however, resulting in frustration and disappointment.
Against these frustrations inherent in modernization, kinship ties provided
security and economic support.

     The family-generally an extended one-was the central relationship in the
lives of most Indonesians. Personal welfare, as well as care for the
handicapped, was considered a family matter. Family networks also provided
employment opportunities for members. Although there was no specific ideal
family size, in general, children were desired as insurance for care in the
parents' old age. At every level of society, kinship and marriage reinforced
economic and social alliances.

Geography and Population

     Indonesia stretches some 5,120 kilometers from east to west across the
equator, the greater part being below the equator (see fig. 1). It is the
largest archipelagic nation in the world, encompassing 13,677 islands and
having a land and sea area of 4.8 million square kilometers, of which only
approximately 1.9 million square kilometers are land. Laid over a map of the
United States, the archipelago would considerably overlap New York and San
Francisco.

     Its geographic location at one of the world's major crossroads has made
Indonesia strategically important in the context of regional and superpower
rivalries. The country forms a natural barrier separating the Indian Ocean,
the South China Sea, and the Pacific Ocean. With Malaysia, it commands the
Strait of Malacca-one of the world's busiest waterways. Through its islands
also pass other important sea routes from the Suez Canal and the Persian Gulf
to China, Japan, and North and South America, including the passages of Selat
Sunda, Selat Lombok, and the Makassar Strait. Travel between Australia and
East Asia, as well as to North America, must also traverse the archipelago.

     The country incorporates the territory of the former Netherlands Indies
and Portuguese Timor. It shares land borders with Malaysia on the northern
part of the island of Borneo and with Papua New Guinea on the island of New
Guinea. Indonesia is separated from Malaysia by the Strait of Malacca, from
the Asian continent by the South China Sea, from the Philippines by the
Celebes Sea, and from Australia by the Timor Sea and the Arafura Sea.

     The government considers the issues of territorial waters and sea limits
to be important elements in the protection of national security and natural
resources, for example, in the control of pollution and oil spills. It
maintains that, as an archipelagic nation, Indonesia's territorial waters
include all sea areas within a maritime belt of 12 nautical miles drawn from
a baseline connecting the outer perimeter of its islands. All straits, bays,
and waters within the baseline are considered inland seas. As for fish
resources and the seabed area, the government claims control over those areas
within 200 nautical miles from the baseline, a position that reflects the
increased economic importance of offshore petroleum and other resources. In
the 1973-81 period Indonesia concluded a series of agreements regarding
continental shelf boundaries with Malaysia, Thailand, India, Papua New Guinea,
and Australia. As of late 1982 its claims to sections of the South China Sea
north of the Natuna Islands overlapped those declared by the Socialist
Republic of Vietnam (Vietnam) in the late 1970s.

     Since the early 1970s Indonesia and Malaysia have challenged the
international status of the Strait of Malacca, claiming instead that these
waters are part of the territorial waters of both nations. They have asserted
that access to the strait can only be gained by other nations under the right
of innocent passage and have requested that all foreign warships notify both
governments before moving through those waters. The United States and several
other nations do not accept these claims, however, and maintain that the
Strait of Malacca is an international waterway and therefore open to all ships
under the right of free transit.

     Although there is no dispute about the territorial boundaries between
Indonesia and the Malaysian provinces of Sabah and Sarawak on the island of
Borneo, in the early 1960s Indonesia strenuously objected to the incorporation
of both into Malaysia. Since that time, however, the occasional territorial
disputes of the boundary were related to local tribal matters rather than to
geographical boundary disputes.

     Western New Guinea was brought under Indonesian administration in 1963
through the United Nations-sponsored Act of Free Choice, after a lengthy
confrontation with the Dutch government. The Portuguese part of the island of
Timor became a province of Indonesia in July 1976, after Indonesian
"volunteers" landed in the territory to counteract what Indonesia saw as a
growing threat to its own security from a leftist, anti-Indonesian political
group that was gaining ascendancy (see The New Order under Soeharto, ch. 1).

Topography

     The Indonesian archipelago has a highly complex geological history, which
has resulted in the nation's volcanic soil conditions, numerous mountain
systems, and varied flora and fauna. The nation comprises three separate
geologic areas. In the west the main islands of Java, Bali, and Sumatra, with
Indonesian Borneo (Kalimantan) and the lesser islands between them, rise from
the submerged Sunda Shelf, which is considered a continuation of the Eurasian
continent. In the east the island of New Guinea (the western portion of which
is the Indonesian province of Irian Jaya) and a few associated island groups
are exposed parts of another submerged platform that is part of the Australian
continent. Between these two shelves in a sea area of great depth lie several
islands, including Sulawesi and the Malukus. A geologic formation outside the
archipelago, the Java Trench, has also affected the nation's topography. Lying
to the west of Sumatra and to the south of Java at the easternmost extent of
the Indian Ocean, the deep marine trench is a very active seismic region, its
deepest point off the coast of Java descending to a depth of 7,317 meters.
According to the theory of continental drift, the Java Trench marks the line
where the Indian continental plate plunges under the Eurasian plate. Their
intersection has produced the ridge on the several islands off the coast of
Sumatra and the mountain systems that run from Sumatra in the west to the
atolls of the Banda Seas in the east.

     The three geologic areas correspond to three sea regions, one of which
encompasses the Java Sea, the Strait of Malacca, and the southern part of the
South China Sea. The shallow waters of the Java Sea, a major national and
international trade artery, are less than 185 meters deep. They are free from
strong currents and are protected from the heavy storms and typhoons that
usually trouble the waters north of the island of Borneo or the Philippines.

     The second region, the Sahul Shelf in the easternmost part of the
archipelago, presents a similar picture. Most of the part of this shelf within
the Indonesian territory is covered by the Arafura sea, which has an average
depth of less than 200 meters. Its waters, too, are calm, but the sea is not
as busy as the Java Sea. It has never been of great significance in either
international or internal trade, and most activities are limited to small
fisheries.

     The third maritime region, encompassing the Banda and Flores seas, lies
between the Sunda and Sahul shelves. Here the average depth is 10 times
greater than in the other two regions. The floor of the Banda Sea presents a
most astonishing terrain of uplands and lowlands; the Lucipara Islands group,
among others, rises above the surface to indicate the presence of submerged
mountain ridges. Earth movements are still taking place in this region,
causing tidal waves with extremely complex ocean currents. Local fishermen
avoid venturing too far from land. The presence of coral reefs and atolls is a
further hazard to seafarers.

     Besides its complex sea condition, Indonesia is also a highly volcanic
region. There are two main mountain systems intersecting in Sulawesi and
Halmahera, one of the Maluku Islands. The first system consists of two
parallel ridges running through Sumatra, Java, Bali, and Timor, curving
sharply to Ceram and Buru. The second runs through the Philippines into
eastern Indonesia. The complexity of the mountain structures and the highly
varied elevations throughout Indonesia affect climatic conditions and the
humidity of the region.

     It is estimated that over 100 peaks are still active volcanoes. They are
located along the more recently formed system of mountains that passes through
Sumatra, Java, and the Lesser Sunda Islands. Almost all are of the composite
type wherein lava escapes not only through a central cone but also through
cracks in the side, giving rise to the formation of parasitic craters. Of the
128 active volcanoes in different parts of Indonesia, 70 have erupted. In 1883
Krakatau, for several centuries a dormant volcano, suddenly erupted, and the
explosion could be heard as far as Australia. The volcano is still active.
Volcanic eruptions have led to much destruction, as was the case of the
eruption of Mount Agung in Bali in 1963 and of Mount Galunggung in Java in
mid-1982; but offsetting this, volcanic ash has fertilized the soil (assuming
the ash is not acidic), and the slopes of the volcanoes, normally composed of
rocks that retain water, form natural underground reservoirs. The height of
the volcanic peaks forms a barrier to rain-bearing winds, and precipitation
falls in greater amounts on the windward side.

     Like other volcanic zones, Indonesia suffers from earthquakes. The
aftereffects, in the form of tidal waves, are often more disastrous than the
earthquakes themselves. Sulawesi and the surrounding area suffer frequently
from earthquakes of varying magnitude, but fortunately most are centered not
on land but under the surrounding seas at considerable depth.

     Coastal plains on many islands are being broadened by the process of
erosion and siltation that has continued over the centuries. Every year the
rivers bring down large quantities of silt to be deposited on the lowlands. It
is estimated that the eastern coast of Sumatra is being extended eastward at a
rate of 91 meters per year, while the northern coast of Java is increasing by
2.7 meters per year. Despite the rapid siltation taking place, the rivers of
the large islands, which are really flooded river valleys, have comparatively
wide estuaries. Excessive siltation is responsible for the absence of good
deep harbors on the coasts of the major islands facing the Strait of Malacca,
the Java Sea, and the South China Sea. Dredging has to be carried out
constantly to keep them deep enough for navigation.

Geographic Regions

     The Indonesian islands are commonly divided into four groups. The first
of these is composed of the larger islands, formerly known collectively as the
great Sunda complex, consisting of Sumatra, Java, Borneo, and Sulawesi. The
second is made up of the islands east of Java from Bali to Timor, known as the
Little or Lesser Sunda Islands. The Maluku Islands between Sulawesi and the
Lesser Sunda Islands comprise the third group; and the fourth is Irian Jaya,
the western part of the island of New Guinea.

The Larger Islands

     Much of the eastern coast of Sumatra consists of badly drained swampy
lands, where thick layers of peat have formed in many places. The swamps are
as much a barrier to communication and roadbuilding as are the island's
interior mountains. Only one limited area-between the Tamiang River and Asahan
River on the northeastern coast of Sumatra-is relatively free from swamps.
Here lie well-drained plains, whose undulating surfaces and fertile alluvial
soil make them ideal for agriculture, particularly for rubber cultivation.

     In every way, the western coast of Sumatra, delineated by the Barisan
Mountains, differs from the eastern coast. The coastal plain along western
Sumatra is too narrow to permit extensive settlement, and the rivers that
cross it are short and flow swiftly. The only areas of real value for
agriculture are the coastal plain of Aceh and the narrow strip of land north
of Padang, the only important commercial center on the western coast. South of
Padang, heavy surf and the presence of coral reefs discourage shipping.
Vessels tend to avoid ports of western Sumatra and instead pass through Selat
Sunda to sail safely into the Java and South China seas.

     The backbone of the Barisan Mountains runs from the northern tip of
Sumatra to the south and has been a great barrier to east-west communication.
All the island's large rivers originate within it, but they do not create
passes, as in Java. Communication routes tend to run lengthwise along the
mountains rather than across them from west to east.

     From an economic standpoint Sumatra is most important to Indonesia for
its mineral resources. The country's largest oil basin, the Minas field in
central Sumatra, yields crude oil of the light and low sulfur type. Large
deposits of natural gas were found in the Arun field of the Special Territory
of Aceh in 1971 and 1972 (see Industry, ch. 3). Tin, which along with crude
oil constitutes Indonesia's prime earner of foreign exchange, is another
product of the region. It is found on the islands of Bangka, Billiton, Lingga,
and Singkep. Bauxite is found in the Riau Province.

     Java bears little resemblance to Sumatra, although it is structurally a
continuation of Sumatra, with the same mountain systems. Its mountains in no
way impede communication or settlement; however, they have been eroded almost
to base level, and the major roads and railroads simply skirt the foothills of
the volcanoes. Nor have extensive, swampy, water-logged plains built up as on
Sumatra. Although in past centuries ships could travel quite a distance
inland, neither the rivers of Java nor those of Sumatra are much used today
for navigation. On Java the terrain makes road construction quite easy.

     Java is the most heavily populated island, having an average density of
about 700 persons per square kilometer. From the rice farmer's perspective the
superior productivity of Java as a volcanic region outweighs the risk of
living there, although villages and large crop areas have been burned badly by
volcanic eruptions from time to time. Further, the main agricultural activity
in Java is wet-rice cultivation, which requires less land than do other kinds
of cultivation. Teak on the northern part of the island is an important
resource. Drilling of oil also occurs offshore from the northern coast.

     In the Indonesian portion of Borneo, communication between the interior
and the coastal people is difficult owing to ecological conditions. Rivers
have served, and in the early 1980s continued to serve, as transport routes;
however, the silt-laden rivers and their countless tributaries, having only
slight gradients, deposit sediment on the lowland in great volume, forming
wide swamps and sandbars across the estuaries, which inhibit navigation by
large vessels. Floods occurring every wet season are an additional handicap,
making travel hazardous; in the dry season the water level falls considerably,
also hindering navigation. In the upper reaches, rapid waterfalls present
another problem. Road construction is impossible along the marshy coastline,
and it is not economical to build roads through the difficult uplands.

     Attempts have been made to farm the wetlands that are subject to seasonal
flooding, provided that they are free of saltwater contamination; however,
only moderate success has been achieved. The cultivators need to have good
knowledge of the rising and receding patterns of the river because planting
must be done just before the river overflows its banks.

     Kalimantan is Indonesia's principal source of tropical hardwoods and
timber. In many areas deforestation of primary growth has left the island with
secondary jungle. The soil suffers from extensive leaching and accompanying
erosion owing to inappropriate farming methods, and reforestation is not
practiced. The eastern portion of the island is a major source of natural gas,
second only to Arun. The Badak field is a major site, while offshore drilling
takes place in the southern and western portions of the island. Other
resources are nickel, copper, bauxite, and coal, found along the Mahakam
River.

     Unlike the other major islands, Sulawesi has no swamps. It has a steep
interior terrain and a high percentage of elevated land; it has no wide
coastal plains. In many places the actual fault lines can be seen in the steep
cliffs. Although rivers flow through most of the rift valleys, there are
few places where rivers have actually carved out their own valleys. In several
places lakes have formed in the rift valleys; their depths run to as much as
600 meters, and they are surrounded by high mountains. There is no volcanic
activity and little evidence in the soils of earlier volcanism. Yet, Sulawesi
suffers from comparatively frequent earthquakes, originating below the sea.
The local people are reluctant to build permanent homes and cultivate crops
because of this and instead depend on the sea for their livelihood.

     One of Sulawesi's major problems is erosion, especially in the southern
area. The climate is drier there than in the islands to the west, and the
strong winds during the dry season have removed much of the topsoil. The
hilly nature of the terrain encourages further erosion. Sulawesi has very
little lowland, leaving few possibilities for agriculture. The rugged
terrain has hindered communication and cut off existing lowlands from one
another. Coastal shipping is more efficient and economical than roadbuilding,
but at the same time it is difficult because of the extensive coral reefs
lying off many parts of the coast. Ships must approach Ujung Pandang harbor in
the south through carefully charted channels. Because of these difficulties,
Sulawesi is isolated from the other islands.

     The main agricultural products of Sulawesi are copra and coffee grown on
small estates. Rich fishing grounds lie offshore. The major mineral product is
nickel, found in southeastern Sulawesi.

The Lesser Sunda Islands

     The island of Bali and others in the Lesser Sunda Islands are
mountainous. Bali is separated from Java by a shallow strait, less than 2.5
kilometers wide. The essential feature of its landscape is a group of
volcanoes that rise in the northeastern part of the island. Between these
volcanic uplands and a limestone southern peninsula, there is a wide plain,
which is the heart of Bali and where population density is the highest. The
terrain is undulating, and the mountains rise gradually, in no way hindering
communication and agriculture. This area is an example of what can be
achieved by subsistence rice growers in hilly land, given the assets of
fertile soil and adequate water.

     The other islands of the Lesser Sunda Islands, except Sumba and Timor,
have no swamp problem and consist of fertile soil, amenable to agriculture.
The drier regions of Lombok, Sumba, and Timor, the most infertile and
inhospitable islands of Indonesia, suffer from a lack of water, and
drought-induced famine is common. The government has started its development
program in this region by establishing ranches for cattle and horses,
keeping in view the production of beef cattle for domestic consumption and
export.

The Maluku Islands

     The Maluku Islands, historically called the Spice Islands, lie to the
north of the Banda Sea between Sulawesi and New Guinea. Buru and Ceram lie
in the central arc of these islands. For centuries Ambon, a comparatively
tiny island near Ceram, has been the area's most important trading center,
and in the early 1980s it was the most important harbor to the east of
Sulawesi. It has an abundant rainfall, making the growth of timber
possible, but it is not suited for other agriculture. Ambon, surrounded by
coral reefs and atolls, and its marine gardens are renowned for their beauty.

     Halmahera is one of the less well-known islands. Unlike Ceram and Buru,
it is an active volcanic area. The island's main staple crop is sago, a
starchy producer of the sago palm that is used in foods and in textile
stiffening. Eucalyptus trees are also grown for their oil and, along with
spices and shrimp, are exported mainly to Japan. The inhabitants depend more
on fishing than on agriculture for their livelihood.

Western New Guinea

     About 47 percent of the island of New Guinea is Indonesian territory.
Because it is located on a continental shelf, it has much in common with
Sumatra, Java and Borneo. In the south and west, swamp-covered lowlands give
way to shallow seas. The soil, however, has not received the benefit of
volcanic activity during its formation. The island presents virtually all
types of landforms, from lowland plains to high mountains with precipitous
cliffs.

     The core mountains form an almost insurmountable obstacle to overland
communication. Six permanently snow-covered peaks in the central range are
the highest in Indonesia. The southern slope of the mountains forms a wall
along the island, impeding communication between the northern and the
southern part of the Indonesian portion of the island, but the coastal plains
in the northern area are relatively narrow. Farther south, rivers form broad
swamps that merge into shallow seas. Seasonal floods and siltation make the
region's rivers of little value for communication; most can only be
penetrated by small canoes. Not surprisingly, population density is low, and
given the natural environment, the possibilities for agricultural development
and increased habitation in the future are not encouraging. A copper-mining
center around the Ertzberg ranges offers one positive incentive for
immigration, but as yet most of the mine workers are temporary migrants sent
from other parts of Indonesia. They live apart from the indigenous
inhabitants and are unlikely to stay permanently.

Climate

     Indonesia is generally classified as having a tropical climate.
Variations and modifications are brought about by surface relief and by
the position of the islands in relation to the seas that separate them.
Precipitation, the most important element in the climate of the
archipelago, shows great variation over the area as a whole. The equatorial
position of the islands keeps sea-level temperatures, as well as humidity and
air pressure, fairly constant from place to place and from month to month.
Rainfall, by contrast, fluctuates both in total annual amount and in
reliability throughout the archipelago. Altitude and position in relation
to prevailing winds are two of the factors that determine its distribution.
Virtually all of the islands receive some amount of rainfall. In parts of
Sumatra, Borneo, and western New Guinea, precipitation exceeds 300
centimeters a year, causing extensive leaching of the soil and the development
of large swamps. Yet in some parts of the Lesser Sunda Islands, an
insufficient total annual rainfall, together with a prolonged dry season, is a
great handicap for agriculture.

     Most of the rainfall is associated with the two monsoons that blow at
alternate times of the year. Some precipitation is also obtained from the
lighter, local winds that blow in the months between the monsoons. The two
monsoon winds, generally referred to as the East and West monsoons, blow in
toward the equator from a southern and a northern direction, respectively.
Indonesia's geographical position as an archipelago between two large
continental areas is important in the building of the wind pattern of the
area. In July and August, high pressure over the desert of Australia causes
winds to move from that country toward the northwest. As the winds reach the
equator, the rotation of the earth causes them to be deflected, and they
turn in a northeastward direction toward the southeastern Asian mainland.
During January and February a corresponding high pressure system over the
Asian mainland causes the pattern to be reversed. The resultant monsoon is
strengthened by additional windflows from the Indian Ocean. The reinforcement
makes this West Monsoon more significant in the yearly climatic pattern than
the weaker East Monsoon, which carries less moisture. The West Monsoon is the
most important season for agriculture. Yet, local topographical conditions
greatly modify the general wind pattern.

     Areas in the archipelago can be distinguished on the basis of mean annual
precipitation. Rainfall is heaviest (exceeding 295 centimeters) in the western
coast and uplands of Sumatra, central portions of Borneo and Sulawesi, the
mountains of western New Guinea, and a few isolated districts in Java, Bali,
Lombok, and Sumbawa, where high peaks advantageously placed in relation to
the prevailing winds encourage heavy precipitation. In comparison with the
rain forest, most other portions of Sumatra, Borneo, Sulawesi, and western New
Guinea, as well as western and central Java, receive moderate rainfall and are
thus better suited to agriculture. The third area, having rainfall less than
195 centimeters, includes small parts of northeastern Sumatra, north of
Langsa; most of eastern Java; all of Madura; the greater part of the Lesser
Sunda Islands; a small part of southern New Guinea, and-southward from
there-the Aru and Tanimbar islands in the Arafura Sea. In this area there is
a lengthy dry season and an increase in unreliability in both total amount
and monthly distribution of rain. The last area, which has rainfall as low as
87.5 centimeters or less, covers 0.6 percent of the national territory,
mostly in the Lesser Sunda Islands, the eastern tip of Java, and two parts
of Sulawesi. Here the main problem is the extremely irregular distribution
of rainfall, which prevents farmers from ever being sure when to plant
their crops.

     Unlike precipitation, temperature throughout the Indonesian archipelago
is relatively constant over the year. Seasonal change is negligible because of
the equatorial position of the country and the modifying influence of the
surrounding seas. Altitude is the most significant factor in temperature
modification. Changes in temperature as a result of varied altitude often
give rise to frosts at night, particularly where there are sheltered
depressions rather than open mountainside.

     In all parts of the archipelago, fluctuations in precipitation rather
than any noticeable change in temperature define the seasons. Fog is fairly
common in areas above 900 meters. Another important climatic element in
tropical areas of Indonesia is evaporation. The rate at which moisture is lost
into the atmosphere influences plant growth as well as soil formation and
erosion. Where leafy forest covers the ground, as in the interior rain forest
of Borneo, much of the rain never reaches the soil. This circumstance,
coupled with ill-planned deforestation, has caused much of the once
forest-covered area to be bare and infertile.

     There is very little change in the length of daylight hours. The
difference between the longest day and the shortest day of the year is only
48 minutes. Because of the great distance from one end to the other, the
country is officially divided into three time zones, corresponding with the
three major geologic subregions of the country. The first one, the Sunda Shelf
region, is in the west at Greenwich mean time (GMT) plus seven hours; the
second, in the region of deep seas and geological instability, is at GMT plus
eight hours; and the third, the Sahul Shelf region in the east, is at GMT plus
nine hours.