Geography

Tom Abbott, Biddulph High School and made available through www.sln.org.uk/geography and only for non commercial use in schools

Tropical rainforest modelsTropical rainforest models

GeographyTropical Rain Forest

Geography

-found near the equator

-temperature varies little from approximately 23°C

-the length of daylight varies from 12 hours by less than one hour

-rainforest>2000mm

Tropical Rain Forest

GeographyTropical Rain Forest

-canopy trees up to 55 m tall

-largest biome, on an area basis

-soils are generally unfertile

-nutrients and carbon stored in plant biomass, not soils

GeographyTropical Savanna/Seasonal Forest

Geography

-found in the tropics (but > 10° latitude)

-pronounced dry seasonwith <5 cm rainfall in some months

Tropical Savanna/Seasonal Forest

GeographyTemperate Forest

Geography

-distinct winter season, frost a defining feature

-summer season usually moist with ppt > evapotranspiration

Temperate Forest

GeographyTemperate Forest

-relatively large tree biomass

-also called the deciduous forest, but contains evergreen needle trees as well

Geography

Tom Abbott, Biddulph High School and made available through www.sln.org.uk/geography and only for non commercial use in schools

Rainforest plants And the enormous the number of different species of plants grow in rainforests, with many species occurring only in one particular region. Unlike other forests, rain forests have an abundance of :

Epiphytes plants which live above the ground growing on tree trunks and branches, Example orchids,

ferns, mosses

Climbing plants including large woody climbers called lianas which are rooted in the soil and usually reach thecanopy. The climbers twist around the tree trunks, and loop from one tree to another in the canopy, binding the trees together.

Geography

Tom Abbott, Biddulph High School and made available through www.sln.org.uk/geography and only for non commercial use in schools

Strong scent and bright colours of flowers attract insects which assist in pollination

Strong scent of fruits attracts animals, which feed on the fruit and assist in dispersal of the seeds

Thick, waxy surface of leaves protects against hot sun, heavy rain, and strong winds Aerial roots of

epiphytes absorb moisture from the air

Tall straight trunks no side branches

Thin, smooth bark

Buttress roots Shallow spreading root system

Geography

Tom Abbott, Biddulph High School and made available through www.sln.org.uk/geography and only for non commercial use in schools

Orchid - sun-loving roots attached themselves to branches and absorb nutrients

Pitcher plant - a carnivorous plant.

slippery rim

tendril

Insects falling into the pitcher are digested, and nutrients which are released are absorbed by the plant.

Parasitic plant

Geography

Tom Abbott, Biddulph High School and made available through www.sln.org.uk/geography and only for non commercial use in schools

Structure of the rainforest

The dominant plants in a rainforest are giant trees. The hot wet climate enables them to grow all year round, and they remain evergreen, continuously shedding their leaves and growing new ones.

The average height of rainforest trees is about 45 metres, although the emergence (trees which tower above the others) may go as high as 90 metres. Smaller trees growing the under story (layer between the canopy and the forest floor).

Several layers can be identified within the forest

Geography

Tom Abbott, Biddulph High School and made available through www.sln.org.uk/geography and only for non commercial use in schools

A Emergent tree canopy

B Large trees of Middle layer

C Lower tree layer

D Shrub/small tree layer

E Ground vegetation

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Geography

Tom Abbott, Biddulph High School and made available through www.sln.org.uk/geography and only for non commercial use in schools

Canopy layer - formed by the crowns of the tall trees and contains a mass of branches, Leaves, flowers and fruit. Conditions in the canopy vary, and include: •Hot sunshine •Heavy rainfall •Tropical storms

Middle layer - the Vegetation here is more sparse. The trees tend to have pointed crowns and, when a giant tree falls, they grow quickly to fill a gap in the canopyConditions within the forest on more or less constant: •There is little variation in temperature •The air is moist and still •Rain on the canopy drips to the forest floor several minutes later •A breeze is rare, even during storms

Geography

Tom Abbott, Biddulph High School and made available through www.sln.org.uk/geography and only for non commercial use in schools

Shrub layer - scattered shrubs, saplings (young trees) and ferns.

Herb layer - a few non-woody, soft stemmed plants with thin leaves.

Leaf litter - thin layer covers the forest floor.

Soil layer - most roots growing the top 10 centimetres whether nutrients are found.

Geography

Effects of DeforestationEffects of Deforestation

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Tom Abbott, Biddulph High School and made available through www.sln.org.uk/geography and only for non commercial use in schools