TROPICAL RAIN FOREST

A. Background

Tropical forest, or often also written as a tropical rain forest is a forest

biome is always wet or damp, which can be found in the region around the

equator; i.e. approximately at latitude 0 ° -10 ° north and south of the equator.

These forests are found in Asia, Australia, Africa, South America, Central

America, Mexico and the Pacific Islands. In term of English this forest

formation known as the Lowland equatorial evergreen rainforest. Tropical

rainforest Lowland evergreen or briefly called the tropical rainforest.

Tropical rain forests are home to half the species of flora and fauna

around the world. Tropical rainforests also dubbed as the "world's largest

pharmacy" because nearly one quarter of modern medicines come from plants

in this rainforest.

Tropical rain forest communities and habitants vary from rain forest to

desert. The largest continuous mass of tropical evergreen forest lies in the

Amazon valley and South America and extent from lower Mexico across

northern South America from Pacific to Atlantic Ocean. Tropical vegetation of

various types covers extensive areas in the central and western Africa and

almost the whole of the Oriental Region.

The classification of this forest can be based on a lack of water

(saturation deficit). Because, these factor determine transpiration that will

determine biomass and tree height. Other variations of tropical rain forest are a

forest located along the banks of the river called "gallery forest". Efficient

nutrient cycling by microorganisms of the most profitable is a prominent

feature of tropical rain forests. The ability to grow fast and thick on the ground

is fertile. If the primary forest in the cutting it will be replaced by secondary

forest. Secondary forests seems to be very tight, the situation reached its climax

is usually very slow, especially on sandy soil in nutrient poor soil. This is

because due to loss of nutrients in forest biomass is harvested and washed for

recycling by soil microbes.

1. Problems

a) What is the tropical rain forest?

b) How is the climate in the tropical rain forest?

c) How is the vegetation in the tropical rain forest?

d) How is the animal adjustment in tropical rain forest?

2. Objective

a) To understand about the tropical rain forest

b) To understand about the climate in tropical rain forest

c) To understand about the vegetation in the tropical rain forest

d) To understand about the animal adjustment in tropical rain forest

B. Tropical rain forest

Tropical rain forest occur in the areas which near to equator. It has only 2

season, dry and wet season. There is no high temperature difference during wet

season and dry season. The soil always very high humidity so the tropical rain

forest is evergreen. The largest continuous mass of tropical evergreen forest

lies in the Amazon valley and South America and extent from lower Mexico

across northern South America from Pacific to Atlantic Ocean. Tropical

vegetation of various types covers extensive areas in the central and western

Africa and almost the whole of the Oriental Region. Tropical vegetation also

occurs in Australia, New Guinea and Pacific island.

Base on the stratification of the rain forests are generally composed of the

layers

1. High layer with a towering canopy trees scattered among the others

2. Canopy layer, the tree canopy with the same average high (80-100 feet)

that covers all parts of the forest that always green

3. Under a lower tree layer of the tree canopy. Its growth mainly on the forest

floor that gets breakthrough sunlight.

Figure 1. The stratification on tropical rain forest (sources: Anonymous,

1994)

C. The Climate of Tropical Rain Forest

The tropical climate is high temperature throughout the year. The

temperature relatively uniform length of day and night. It has seasonal

variation in rainfall. There are two seasons, dry and wet seasons. Mean

monthly temperature is never less than 180C (640F) to 320C (900F) or higher.

There is a greater range in temperature at different times day and night than in

mean monthly temperature throughout the year. Mean daily minimum and

maximum temperature are seldom bellow 100C (500F) or above 43,30C (1100F).

But, the mountain slopes is a drop in temperature. Sometimes clouds are covers

the mountain slope.

Figure 2. Clouds in mountain slope (sources: Anonymous, 2011)

The rainfall in tropical rain forest is about 200-225 cm every year. The

rainfall results from the cooling of the air that rises from heated land surface.

During the dry season the soils become desiccated. While during the wet

season it becomes waterlogged. In the wettest part of the tropical rain forest,

the relative humidity is always very high. It seldom drops below 60% of

saturation during the hottest part of the day and average over 90% for entire

day.

D. The Vegetation in Tropical Rain Forest

There are thousands tree species in tropical rain forest. A 102 km area

of tropical rain forest may contain 1500 species of flowering plants and up to

750 species of tree. The richest is the lowland tropical forest of the Indo-

Malayan, which contains some 7900 species. There one major groups

Dipterocarpa contain 9 genera and 155 species of which 27 are endemic.

African forest is poorest and uniform in flora.

The tree trunk are straight, smooth and slender often buttressed and

reach 25-30 m before expending into crown with large, leathery simple leaves.

The bark is colored and often covered with lichens. Climbing plants, the lianas

long, thick and woody, hang from trees like cable and epiphyte grow on the

trunk of limbs. Undergrowth of the dark interior is spares and consist if shrubs,

herbs and fern.

The examples of epiphyte plants are orchid (Dendrobium haselti), bird

nest fern (Asplenium nidus), mosses and lichens. Climbing plants usually found

are vanilla (Vaniela planifolia) and rattan (Calamus sp.). The saprophyte plants

digest the dead organism. They are orchid (Galeola javanica) and several kinds

of fungi. The other is parasite plants such as Custata sp. Rafflesia sp.

Balanophora, Kortasella, etc. They get nutrition from the other plants by

embed the haustorium roots into the tree stalk. The most unique plant is

pouchlike plants. It found in Indonesia separated in Java, Sumatra, and

Kalimantan. It is a climbing and epiphyte on the big woody trees. The example

of pouch like plants is “kantung semar” (Nephentes gymnaphora).

The tangled vegetation is popularly known as jungle. It is the secondary

growth (second growth) forest that develops where primary forest has been

disturbed. The secondary forest contains herbs such as Musanga (Africa),

Cecropia (America), and Macrolanga (Malaysia). Secondary forest look

luxuriant but it is largely different from primary forest looked prom the

ecology and floristic. The climax need very long time to return. We have to

conserve the tropical rain forest to keep the great biodiversity.

a. b. c. d.

Figure 3. Vegetation of tropical rain forest

a. Woody liana

b. Dendrobium haselti

c. Vaniela planifolia

d. kantung semar” (Nephentes gymnaphora).

(sources: Anonymous, 2011)

E. Animal Adjustment

Like the flora, the fauna in tropical rain forest is very rich in species.

Correlated with this harshness and severity and inter specific competition and

predation. On the other hand, except for ant and termites, few species rich high

levels of population density. Although total population all of species may be

high in tropical region, the density of individuals per species in tropical region

in low.

The types of animals that can be found in the rainforest are a kind of

chameleons, tree lizards, gecko, snakes, frogs and birds. Orthopthera insects

from butterflies and moths are very important ecosystems here. About a 500-

600 butterfly species found in America. There are also a number of mammalian

herbivores in it and there are animals that mimicry (the ability to change the

color of his skin) to defense himself.

Animal residents are not scattered across the forest, but only on the layer-

specific layer which can support their live, according to his ability to adapt the

animal was kubuk coney (Cynosephalus variegatus), flying snakes

(Chrisopelela Paradisi), fruit bats (Pteropus vampyrus), orangutans (Pongo

pygmaeus), kite-kite (Hylobates moloch), gibbon (Hylobates syndactilus),

towering crest brown (Rhytoceros undulatus), blue leaf spot (Chloropsis

cochiechinensis), serpent eagle, leopard (Anthera pardus), pangolin (Manis

javanica), chameleon (Calotes jubatus), lemurs (Nicticobus coucang), deer

shoots snakes (Dyroptis prisinus), kaktua (Cacatua galerita), elephants

(Elephas maximus), cassowaries (Casuarius casuarius), Javan tiger

(Rhinoceros sondaicus).

Animals that are widely distributed insects Rhiodininae example (a type of

butterfly-colored metal) is an American fauna spread reached 100 genera. The

Hymenoptera, Diptera, and Coleoptera are, in general the best representated

groups among the insects (Brisco:1952). Cold blooded animals, particularly

Reptiles and Arthropods, reach their largest adult sizes in the tropics. In the

Amazon forest there is a spider large enough to catch and feed on small birds

there are caught in its wec (Btes: 1864). Some moths have a wing-spread on 30

cm a Milipade reaches a length of 28 cm, and a slug 20 cm. Birds and animals

however, are usually smaller than their relatives in temperate regions. Birds

also lay fewer eggs in clutch than they do temperate region.

Figure 4. Giant Armadillo Figure 5. Pangolin

Figure 6. Primate Figure 7. Snake

Figure 8. Scorpion Figure 9. Bird

(sources: Anonymous, 2011)

F. Conclusion

1. Tropical rain forest occur in the areas which near to equator. The soil

always very high humidity so the tropical rain forest is evergreen.

2. The temperature relatively uniform length of day and night. It has seasonal

variation in rainfall. It has only 2 season, dry and wet season.

3. The vegetation in tropical rain forest is large vary in species, it content of

woody trees, epiphyte, parasite, saprophyte, climbing plants, and pounce

plants.

4. The animal in tropical rain forest can found in the specific layer or in all

of layers according to its ability to adapt. The animal on the specific layer

which can support their live, according to his ability to adapt the animals

are reptile, mammals, and aves. The animal can adapt on all of layer are

insects.

REFERENCES

Kendeigh, S. Charles. 1980. Ecology. New Delhi : Prentice Hall of India Private

Limited

Odum, Eugene P.1998.

Odum, Eugene P. 1996. Dasar-dasar Ekologi. Jogyakarta: Gajah Mada University

Press

Southwick, Charles A. 1985. Global Ecology. Colorado : Sinaver Associated Inc.

Publisher

Stralhler, Arthur N. Strahler, Alan H. Elements of Physical Geography. USA:

John Wiley & Sons. 1997

Anonymous. Rain Forest. 2011. (online). www.cotf.edu, accessed on January 20th,

2012

Glossary

1. Epifit merupakan tumbuhan yang hidup menempel pada substrat.

Tumbuhan epifit di hutan hujan tropis biasanya menempel pada

pohon-pohon berkayu. Contoh-contoh tumbuhan epifit antara lain anggrek

(Dendrobium hasselti), paku sarang burung (Asplenium nidus) dan

tumbuhan lumut (Politricum sp.). selain menempel pada pohon-pohon

berkayu, tumbuhan tersebut juga dapat menempel pada bebatuan.

2. Tumbuhan parasite adalah tumbuhan yang menancap pada tumbuhan

inang untuk mengambil unsur hara pada batang.

Tumbuhan parasite mengambil zat hara dari inang dengan

menancapkan akar peresap hingga menembus xylem inangnya. Contoh

tumbuhan parasite antara lain benalu ( Cuscuta sp., Rafflessia sp.,

Balanophora, Korthasella dan lain-lain.)

3. Tumbuhan berkantung merupakan tumbuhan yang menyerupai kantung.

Tumbuhan berkantung merupakan tumbuhan pemanjat dan epifit

pada phon-pohon besar pada ketinggian sampai 18 meter. Jenis tumbuhan

berkantung terdapat pada hutan di Indonesia yang tersebar di pulau Jawa,

Sumatra, dan Kalimantan. Contohnya kantung semar ( Nephentes

gymnaphora)

4. Flora adalah berbagai jenis tumbuh-tumbuhan yang ada di muka bumi.

Flora yang terdapat pada hutan hujan tropis sangat kaya akan jenis

dan jumlahnya. Hutan hujan tropis kaya dengan jenis pohon yang tinggi.

Selain itu terdapat pula tumbuhan memanjat, epifit, saprofit, dan parasite.

5. Fauna merupakan berbagai jenis hewan yang hidup di muka bumi.

Berbagai fauna yang terdapat di hutan hujan tropis sangat beragam

meliputi arthropoda, berbagai jenis burung, mamalia, reptile, dan amfibi.

Satwa penghuni hutan tidak tersebar di seluruh pelosok hutan melainkan di

lapisan-lapisan tertentu saja. Habitat fauna di hutan sesuai dengan

kemampuan adaptasinya.

6. Plasma nutfah adalah sumber keanekaragaman hayati yang diperoleh dari

alam.

Perusakan hutan dapat menghilangkan sumber plasma nutfah.

Plasma nutfah dikonservasi agar tidak punah. Hutan hujan tropic

menyediakan sumber plasma nutfah yang merupakan bahan yang penting

untuk keperluan masyarakat ilmiah.

7. Kompetisi adalah peristiwa perebutan makanan atau dereh kekuasaan antar

spesies yang berbeda.

Kompetisi terjadi karena satu relung ekologi ditempati oleh

beberapa spesies yang memiliki sumber makanan yang sama. Keterbatasan

sumber nutrisi dapat memicu kompetisi. Kompetisi juga sering terjadi

dengan latar belakang perebutan daerah kekuasaan.

8. Mimikri adalah suatu bentuk pertahanan diri dengan dari musuh dengan

merubah warna permukaan tubuh.

Hewan yang mimikri dapat merubah warna permukaan tubuhnya

sesuai tempat dimana ia berada. Hewan yang dapat melakukan mekanisme

mimikri adalah bunglon. Hewan tersebut merubah warna tubuhnya agar

tidak terlihat oleh pemangsa.

9. Lapisan tinggi adalah stratifikasi hutan hujan dengan pohon yang

menjulang tinggi.

Lapisan tinggi tersebar yang menjulang dia atas lapisan umum.

Pada lapisan tinggi terdapat tumbuhan Ficus sp. Pohon-pohon yamg tinggi

berakar dangkal dan sering mempunyai banir-banir yang mengembang.

Pada pohon-pohon tertentu dapat ditemukan tanaman epifit.

10. Lapisan tajuk (canopy layer) mmerupakan pohon-pohon yang sama rata

tingginya.

Lapisan tajuk menutupi seluruh bagian hutan. Lapisan tajuk terlihat

selalu hijau sepanjang tahun (evergreen). Lapisan tajuk membentuk

permadani hijau yang berkesinambungan tingginya antara 80-100 kaki.

11. Lapisan pohon bawah merupakan statum yang lebih rendah daripada

lapisan tajuk.

Pertumbuhan tanaman pada lapisan bawah sangat rapat terutama

pada lantai hutan. Lapisan pohon bawah mendapat terobosan sinar

matahari. Pada lapisan tersebut terdapat semak dan herba, seringkali

mengandung sejumlah paku-pakuan dan palma.

12. Herbivora adalah hewan pemakan tumbuhan

Dalam hutan hujan tropis banyak terdapat hewan yang tergolong

hebivora. Hewan herbivora tersebut adalah golongan primata dan burung

pemakan biji. Burung-burung trsebut tinggal di dalamnya, contoh dari

jenis hewan tersebut adalah kakaktua dan kasuari.

13. Hutan sekunder adalah hutan yang terbentuk setelah hutan primer

mengalami kerusakan.

Flora yang terdapat pada hutan ini adalah pohon-pohon yang lunak.

Pohon-pophon tersebut banyak ditemukan di Afrika seperti Musanga, di

Amerika adalah pohon Cercopia, dan di Malaysia adalah pohon

Marcoronga. Hutan sekunder perkembangannya lebih lambat dari pada

hutan primer.

14. Hutan primer adalah hutan yang masih lebat dan belum tercampur tangan

manusia.

Di dalam hutan primer terdapat pohon-pohon yang tinggi dan

lebat. Flora dan faunanya bermacam-macam. Flora pada hutan ini

mencakup tumbuhan epifit, parasit, dan berkantunmg. Sedangkan macam

faunanya mencakup mamalia, amphibi, aves dan reptil.

15. Predasi adalah suatu peristiwa makan (memangsa) dan di makan

(dimangsa).

Dalam peristiwa ini biasanya di kenal dua istilah lagi yaitu :

predator dan mangsa. Dalam kehidupannya hewan yang kuat akan

menjadi predator sedangkan hewan yang lemah aka menjadi mangsa

hewan yang yang lebih kuat. Contoh dari peristiwa predasi adalah didalam

sebuah hutan yang liar seekor harimau memangsa seekor rusa untuk

mekehidupannya, disisni harimau sebagai predator sedangkan rusa sebagai

mangsa.