Natural Vegetation

r

Plants that grow naturally in a place with little or no human interference

Tropical RAINFOREST

Tropical Equatorail Climate

10N & S of the Equator

Amazon Basin, Congo Basin, parts of SEA

High temp (abt 27C)

High r/f (>1500mm)

5 distinct layers

Emergent

30-50m

Crowns abv canopy

Tall, Straight, thick Trunks

Canopy

15-30m

wide,shallow,umbrella shaped crown

Forms con't leaf cover

r

AKA Canopy

Prevents sunlight frm penetrating

Plants

Epiphytes

r

Plants that have adapted to low light condition by growing on tree branches to get more sunlight.

Bird nest ferns, orchids

Grows on & use trees as physical support.

Rainwater & decaying leaves collected @ the joints of branched = water & food

Lianas

r

Thick woody vines that wind arnd tree trunks to reach for sunlight.

90m

Parasitic plants

Cause harm/death to host trees

Strangling fig

Wrap itself arnd trunk of host -> compete w/ the host for space, sunlight & nutrients

Understory

6-15m

Narrower, oval-shaped crowns

Grow whr gaps in the canopy allows sunlight to pass thru

Shrub

<6m

Tree saplings and woody plants

Undergrowth

<5m

v. little sunlight reaches this layer

Sparse

Grasses, Ferns, Mosses & fungi

Leaf litter

decompose-> humus->supports abundant vegetation growth

Features

Leaves

Broad

Max surface area for photosynthesis

Evergreen

r

Leaves remains green all yr rounddon't shed their leaves at the same time in the year.

Waxy w/ drip tips

Rainwater drain off easily

prevent harmful bacteria frm growing on them

prevents plants from diseases

Branch and Bark

Smooth and Thin

r

No need for protection against cold/dry

Branches only @ top 1/3 of trunk

Spread out like umbrella=> get as much sunlight as they can

Roots

Buttress Roots

Supposrts great wt of the tree

Shallow and spread widely

r

do not need to reach deep into soil for water and nutrients

Fruits and Flowers

Brightly coloured

r

still air below canopy=>pollination can't be wind

Produce fruits thruout the yr

IMPORTANCE

DEFORSTATION in Kalimantan

r

permanant clearing & destruction of forests

Causes

growing world's popn

more & more pple depend on the forest as a resource

dd for land ^^^

crowded places, esp cities

forests cleared to create more land for settlements, agri and industry

^^ in dd for agri landuse

indon govt popn resettlement prog to ease overcrowding in islands such as java and sumatra => many indons resettled in K

growth of settlements

improved transport networks

growth of industries

forests fires

Problems

Policies

Water Quantity

plays impt role in water cycle

maintain water supply

r

enable water to be collested & stores within a water catchment

Central Catchment Nature Reserve in SG

Tropical MOONSOON forest

Features

Leaves

Deciduous

Shed leaves during dry season

minimise water loss thru transpiration

Leaves grow agn quickly during rainy season

Waxy with drip tips

Narrow

Bamboo

minimise loss of water thru transpiration

Roots

Deep roots

tap water sources deep underground as rf is not regular thruout the year

Bark and Branches

Thick & coarse

Protects trunk frm heat & dryness during dry season

Withstand extreme heat frm natural forest fires(occassionally)

Branches located arnd the middle of trunks

r

Grows less dense than TRF =>sunlight reach lower parts of forest

Fruits and Flowers

Many bear fruits duning dry season when they're leafless

Trees

mostly hardwoods

Commercially valuable ones incl, sandalwood, teak, sal

Tropical Moonsoon Climate

r

Due to moonsoon winds

High temp(abt 26C)

High r/f (>1500mm)

Distinct wet & dry seasons

S.Asia, SEA, S. China, N. Aus

btween 10 & 25 N & S of the Equator

3 Layers

Canopy

25-30m

Plants

Understory

Abt 15m (6-15m)

Undergrowth

Bamboo thickts, grass

wet season-> dense

Dry season -> less dense

6m

MANGROVE Forest

Location

mainly tropical climate

Along sheltered coastal regions & places whr rivers constanly deposit clay & silt

23.5N & S of the Equator

Structure

r

Horizontal zones, not vertical

Coastal zone

Nearest to the coast

flooded w/ salt water

adapted to growing in brackish water

Avicennia & sonneratia

Breathing/ aerial roots

Middle ~

Prop/stilt roots (air ventricles)

Rhizophora

Inland ~

Knee-like roots

Bruguiera

r

Least tolereant of salt water

Plants

salt-tolerant (halophytes)

sea hibiscus, Nipah plam

Features

Leaves

Evergreen

Broad

Drip tips

Thick & leathery

Reduce water loss thru transpiration (due to high temp)

Adapted to regulate amt of salt on tree

Salt secreters

Avicennia

Secrete xs salt on leaves, removed by wind/rain

Ultrafiltrators

Rhizophora & sonneratia

Absorb salt, store xs salt in old leaves which then fall off

Flowers & fruits

Bouyant

waves & currents carry to new coastal area to take roots

Avicennia

Germinates while attached to parent tree

Elongated structure

Sharp tips helps fruit anchor in soft muddy soil

drops directly into ground and grows

Rhizophora

Colourful

attract insects

Bruguiera

bright red lantern-shaped flowers

Roots

Aerial roots

takes in oxygen

Avicennia & sonneratia

Prop roots

anchors tree firmly into muddy soil

rhizhopora

Kneed roots

provide firms suppost on the soft soil

bruguiera

CONIFEROUS Forests