Lecture VIII - PowerPoint Presentation

Slide1

Lecture VIII

RainforestSlide2

R

ainforest

Nobody is sure how intensive

tropical rainforest

once were. One of the widely accepted estimates is that they covered 25 million square kilometers, or 16% of the land surface of the earth. Today, they cover around ten million kilometers. Half of the loss has been attributed to permanent farms conversion; a quarter to the development of

pasteurland

, livestock and ranches; and another quarter to shifting cultivations.Slide3

Rainforest preserve life-giving species and protect millions of living creatures, and regulate the flow of water on earth. Like a gigantic sponge, they soak up water from heavy tropical rainfalls, then release it slowly and steadily, providing a constant supply for people and farmers living hundreds or even thousands of miles away.

Tropical forest also play a crucial role in the global recycling of carbon.

The rainforest are disappearing because people are poor and greedy, and not because they are ignorant or stupid. Most attempts to grow plants and animals in the tropics have been geared to producing food for

substinence

and commodities for cash.Slide4

Causes of Destruction of Rainforests

1. Poverty drives people into the woods for fuel, food and work.

2. Word’s growing demand for wood products (timber) encourages the continued rape of rainforests.

3.

P

oor government policies.Slide5

4. Global increase in the demand for forest products for building constructions, furniture, plywood, firewood, weaving materials, gums, resins, oils, charcoals, even chopsticks for

japanese

restaurants.

5

. Government’s opening of the forest frontiers as a way to bolster the economy, and to relocate people in various settlement programs.

6

. Ever-increasing and growing number of people who live and continue to establish residence in the rainforest.Slide6

Effects of Rainforest Destruction

1. If nothing is done to check global population growth, and to control tropical deforestation, there may be only 20,000 square miles of rainforest left in

te

world by the year 2050, and nothing by 2100.

2. The practice of

slash-and-burn

affects the uncut area, and the remaining trees suffer.

3. In steep areas, logging does not only destroy the forest, but also erodes bare grounds.Slide7

4

. Many valuable chemical compounds are sourced from the jungles. Unfortunately, as the forest are cut, many of these potentially life-saving tropical plants disappear forever

.

5. More than 1,000 tribes of

indegenous

people are close to extinction. The

enroachment

has led to repeated violence and lost lives, mostly among native rubber trappers and settlers.

6. Deforestation releases more than a billion tons of carbon into the air annually contributing immensely to the greenhouse effect.Slide8

Forest Management (Multiple-Use Management System)

Multiple-use sustained management of forest primarily aims to make the greatest number of forest resources available to the greatest number of people. A forest cannot be all things to all people. Sound multiple-use management must weigh the needs of many people and those needs vary according to their values of top priority.Slide9

1.

Forest as Wildlife Habitat

National forest as well as private woodlands offer excellent wildlife habitat.

2.

Forest as Wilderness, Recreational and Scientific Areas

The wilderness is an area where the earth and its community of life are

untrammelled

by man, where man himself is a visitor and does not remain. These areas have to be conserved and preserved for recreational activities and scientific activities.Slide10

3. Forest as Source of Fuel

An alternative source of energy is the biomass of trees, which is renewable. Wood and wood products provide 1.5% of the energy consumed globally.

4. Forest as Source of Wood Production

Philippine forest and wood industry contributed significantly to our Gross Domestic Product (GDP) and export earnings. However, primary and secondary wood-based activities accounted for only 2.5% of the national output in 1988 as compared to 9.8% in 1970. the country even became a net importer for its wood

requirments

in the early ‘90s to date.Slide11

Reforestration

Whenever timber is removed, either by

clearcutting

or by

selective cutting,

the denuded area must be reforested to ensure a sustained yield. Undesirable cutting practices are expected to increase

treefold

by the year 2020, especially farmer-owned woodlots.

Reforestration

--efforts to replant the forest– may be done by either natural or artificial methods.Slide12

1. Natural Reseeding

After

claercutting

, a few mature, wild-firm

tulls

may be left intact as a seed source within the otherwise logged off-site.

Seeds are scattered by the wind, birds, rodents, and runoff water. The seeds are eventually dispersed throughout denuded area. This is

natural reseeding process.

2. Seeding by Foresters

Aerial seeding using planes flying slowly just above the treetops is employed in rugged terrains. In a logged-off site that is flat, power-driven seeding machine is used. These machines plant up to 3.3 hectares per day, and simultaneously fertilize the soil and apply herbicide to prevent weed

enroachment

.Slide13

3. Planting

Actual planting of young trees from plantation stock is a better and more successful means of reforestation. On flat lands. Three workers, a tractor, and a planting machine can set 1,000 to 2,000 trees per hour. Slide14

Causes of Deforestation

Human have already cut down 40% of the world’s closed canopy tropical rainforest. About 105,000 square kilometer are destroyed annually. By estimates, present rates of removal will leave only scattered remnants of tropical rainforest by the year 2025.

1.Slash-and-Burn Agriculture

Much forest destruction can be blamed on

slash-and –burn

or shifting agriculture. This is done by farmers cutting the trees, tilling the land for few years then abandoning or

leving

it fallow – for up to 7 years. Devastating effects are high in too large

clearcut

areas. The fallow period is often too short for soil fertility to be restored.Slide15

2. Fire

Fire

is used as a tool in slash-and-burn farming(

kaingin

system) to dispose of fallen trees and to prevent the invasion of weeds and shrubs in the crop area. Large forest areas have been destroyed when such fire have raged out of control.

3. Cattle Ranching

Large areas of tropical forest are being cleared away for cattle ranching. Hamburger, hotdog, and luncheon meat productions demand the conversion of forest to ranches and gracing lands at the rate of 21,500 square

kilometres

per year.Slide16

4. Gathering Fuel Wood

More than one billion

cibic

mters

of wood are harvested for fuel in the tropics. The wood is either used for firewood or is converted to charcoal.

5. Industrial Logging

Commercial logging in tropical regions is frequently wasteful and inefficient. Most

clearcut

areas do not become reforested by natural means. The land-starved

s

quatters move in to eke out their livelihood through slash-and-burn agriculture.Slide17

Effects of Deforestation

1. Firewood Scarcity

2. Climatic Changes

3. Loss of Genetic “Pools”

4.Extinction of Species

To Save The Tropical Forest

1. Forest industries reseed or replant areas that they have harvested.Slide18

2. Villagers reforest areas from where they have removed trees for use as fuels. Plant fast-growing trees which attain a height of 6 meters (20 feet) in four to five years.

3. Countries with rainforest provide financial grants to support research and education on the ecology and management of tropical forest.

4. Countries with rainforest convert 15% of their forest to national parks and preserves.

5. Provide funding for this project.