par yuhui ng Il y a 15 années
468
Plus de détails
Plants that grow naturally in a place with little or no human interference
Kneed roots
provide firms suppost on the soft soil
bruguiera
Prop roots
anchors tree firmly into muddy soil
rhizhopora
Aerial roots
takes in oxygen
Colourful
attract insects
bright red lantern-shaped flowers
Germinates while attached to parent tree
Sharp tips helps fruit anchor in soft muddy soil
drops directly into ground and grows
Elongated structure
Bouyant
waves & currents carry to new coastal area to take roots
Adapted to regulate amt of salt on tree
Ultrafiltrators
Rhizophora & sonneratia
Absorb salt, store xs salt in old leaves which then fall off
Salt secreters
Avicennia
Secrete xs salt on leaves, removed by wind/rain
Thick & leathery
Reduce water loss thru transpiration (due to high temp)
Drip tips
sea hibiscus, Nipah plam
Horizontal zones, not vertical
Knee-like roots
Bruguiera
Least tolereant of salt water
Prop/stilt roots (air ventricles)
Rhizophora
Nearest to the coast
flooded w/ salt water
Breathing/ aerial roots
adapted to growing in brackish water
Avicennia & sonneratia
6m
Bamboo thickts, grass
Dry season -> less dense
wet season-> dense
Abt 15m (6-15m)
25-30m
Due to moonsoon winds
mostly hardwoods
Commercially valuable ones incl, sandalwood, teak, sal
Many bear fruits duning dry season when they're leafless
Branches located arnd the middle of trunks
Grows less dense than TRF =>sunlight reach lower parts of forest
Thick & coarse
Withstand extreme heat frm natural forest fires(occassionally)
Protects trunk frm heat & dryness during dry season
Deep roots
tap water sources deep underground as rf is not regular thruout the year
Narrow
Bamboo
minimise loss of water thru transpiration
Waxy with drip tips
Deciduous
Leaves grow agn quickly during rainy season
Shed leaves during dry season
minimise water loss thru transpiration
enable water to be collested & stores within a water catchment
Central Catchment Nature Reserve in SG
plays impt role in water cycle
permanant clearing & destruction of forests
Policies
Problems
Causes
forests fires
growth of industries
improved transport networks
growth of settlements
^^ 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
growing world's popn
crowded places, esp cities
forests cleared to create more land for settlements, agri and industry
more & more pple depend on the forest as a resource
dd for land ^^^
Produce fruits thruout the yr
Brightly coloured
still air below canopy=>pollination can't be wind
Shallow and spread widely
do not need to reach deep into soil for water and nutrients
Buttress Roots
Supposrts great wt of the tree
Branches only @ top 1/3 of trunk
Spread out like umbrella=> get as much sunlight as they can
Smooth and Thin
No need for protection against cold/dry
Waxy w/ drip tips
Rainwater drain off easily
prevent harmful bacteria frm growing on them
prevents plants from diseases
Evergreen
Leaves remains green all yr round
don't shed their leaves at the same time in the year.
Broad
Max surface area for photosynthesis
Leaf litter
decompose-> humus->supports abundant vegetation growth
v. little sunlight reaches this layer
Sparse
Grasses, Ferns, Mosses & fungi
<5m
Tree saplings and woody plants
<6m
Grow whr gaps in the canopy allows sunlight to pass thru
Narrower, oval-shaped crowns
6-15m
Plants
Parasitic plants
Strangling fig
Wrap itself arnd trunk of host -> compete w/ the host for space, sunlight & nutrients
Cause harm/death to host trees
Lianas
Thick woody vines that wind arnd tree trunks to reach for sunlight.
90m
Epiphytes
Plants that have adapted to low light condition by growing on tree branches to get more sunlight.
Grows on & use trees as physical support.
Rainwater & decaying leaves collected @ the joints of branched = water & food
Bird nest ferns, orchids
wide,shallow,umbrella shaped crown
Forms con't leaf cover
AKA Canopy
Prevents sunlight frm penetrating
15-30m
Tall, Straight, thick Trunks
Crowns abv canopy
30-50m
