Land Use: Forests and Grasslands. World Land Use.

Land Use: Forests and Grasslands

World Land Use

World Forests Why important?

Provide habitats and food for wildlife Control water runoff Regulate the climate Purify the air

Amount of Forests Left About 3.8 billion ha (1 ha= 10,000 square

meters) Covers around 29% of earth’s land surface

Closed Canopy: Tree crowns are spread over 20% or more of the ground (80% of total forests)

Open Canopy: Tree crowns are spread less than 20% of the ground (20% of total forests)

Forest Distribution

Forest Distribution

Old Growth Forests Old Growth Forest: Forests free from

disturbance long enough to have mature trees, physical conditions, species diversity, and other characteristics of equilibrium ecosystems

In danger due to increase human activity in forests

Less than 50% of forests today retain old growth features

Forest Products Industrial timber has become the major

use of wood in the modern word 3.7 billion metric tons sold per year

Fuelwood represents the other half of wood harvested by humans Supplies the main source of heating and

cooking to third world countries

Forest Management Forest Management involves planning

for sustainable harvests, with particular attention paid to forest regeneration

25% of world’s forests are scientifically managed for wood production

Monoculture Forestry Saves money and labor leading to high profits Promotes the spread of disease and pest

infestations

Tropical Forests Rich biodiversity Contains at least ½ of the earth’s plant,

animal, and microbial species

Tropical Forest Disappearance Between 1990 and 2000, 9-12 million ha

of tropical forest was lost Tropical forest cover decreases at around

0.8% each year Most tropical forests are lost in Africa Fueled by Cattle ranching, fruit

plantations, mining, and illegal logging

Alternatives Milpa/Swidden Agriculture

“Slash and Burn” Prevents erosion, infestation, and tree loss Form of Mixed Perennial Polyculture

Forest Protection Tropical forest reservations are being set

up worldwide Debt-for-Nature Swaps

People in developed countries can aid the preservation of forests

Hope is to reduce debt and preserve wildlife at the same time

Temperate Forests Like tropical forests, temperate forests are

also facing danger because of deforestation

Harvesting Methods Most popular method in U.S. and Canada

is clear-cutting An alternative to this is Selective Cutting

Fire Management Many ecosystems are reliant upon periodic

fires for regeneration Trying to prevent fires in the these

ecosystems will slow its growth, and will also cause bigger fires by building up debris

U.S. government has stopped trying to fight some fires, and are letting them naturally burn Salvage Logging

Grasslands 2nd to forests in amount used and altered

by humans Grasslands have been reduced by 1/3

since the spread of agriculture Pasture: enclosed or managed grasslands Rangeland: unfenced, natural prairie and

open woodland

Management Traditional ranchers can avoid overgrazing

or overusing the land Currently, management is allowing

overgrazing to occur Desertification

Range Conditions in the U.S. Most of livestock do not graze on public

rangelands Lack of enforcement on rangelands led to

overgrazing 55% of U.S. rangelands are in “poor to very

poor” conditions

Rotational Grazing Rotational Grazing simulates the actual

nature of wild grazing animals More healthy for the rangeland Some U.S. rangelands now require

rotational grazing

Land Ownership In most countries, most of the land is

owned by a small percentage of the people Has causes political and social unrest in some

countries Land Reform is an attempt to distribute

land to a greater amount of people May improve environmental conditions

Indigenous Land Rights Use 25% of land on earth Indigenous people often take better care

of their land than modern societies do Indigenous people often have their natural

resources taken away by modern societies

HALFTIME QUESTIONS!!!!!!!!!! What is the difference between a pasture and a rangeland? Name some advantages and disadvantages to selective

cutting Describe the “slash and burn” process Which countries are the largest producers of industrial

timber? What is fuel wood? Which continent experiences the most forest lost per year? What are some important roles that forests play in the

environment? What are some problems with monoculture forestry? Why is trying to prevent forest fires sometimes harmful to

some ecosystems? BONUS: What is one ha equal to in meters?

Chapter 13:Preserving and Restoring Nature

History of Parks In ancient times, parks were for only the

rich and powerful Public Parks were created in the 1800’s First National Park: Yellowstone National

ParkNational Parks have now spread all over the

world

National Parks One or more ecosystems that are not

altered by human activity Sites have scientific, educational, and

recreational value Humans can enter only for scientific,

educational, and recreational, and must not disturb the nature

Parks are protected by the national government

Threats to National Parks Budget issues Pollution Erosion Power plants

Wilderness Areas and Wildlife Refuges Wilderness: An area of undeveloped land

affected primarily by the forces of nature; an area where human are visitors and do not remain

Environmentalists push for more wilderness areas, industrialists want less wilderness

Wildlife Refuges Originally sanctuaries for wildlife Now 550 National Refuges in U.S. Now hunting is allowed Other damaging human activities are also

allowed

Global Nature Preservation World Conservation Strategy: A proposal for

maintaining essential ecological processes, preserving genetic diversity, and ensuring that utilization of species and ecosystems is suitable

4% of earth’s land designated as parks, refuges, and reserves

Europe has highest amount of protected sites Pacific has least amount of sites Amount of actual protection in these areas varies

Marine Preservation Over harvesting is depleting the oceans or

resources Ecosystems like coral reefs are being

destroyed at a rapid rate Scientists have called for increased

amounts of marine refuges Marine refuges shown to be very effective

Man and Biosphere Program

Landscape Ecology Landscape Ecology: The study of the

reciprocal effects of spatial pattern on ecological processes. A study in which the landscape history shapes the features of the land and the organisms that inhabit it as well as our reaction to, and interpretation of, the land.

Considers humans an important part of most landscapes

Patchiness Ecosystems often have patches or certain

types of biotic and abiotic factors Patches shift with time Boundaries of these patches are important

Restoration Ecology Seeks to repair or reconstruct ecosystems

damaged or altered by humans Different degrees of restoration

Restoration Rehabilitation Remediation Reclamation Re-creation

Methods of Restoration Removing foreign organisms Planting organisms that original inhabited

the area Bringing back animals that originally

inhabited the area Letting nature heal itself

Preserving Wetlands 1990’s: Laws passed punishing any who

drain, fill, or damage wetlands with pollutants

Destruction of wetlands has greatly decreased

2001: Laws were then changed so that only around 20% of wetlands were protected

Wetland Migration: creating new wetlands to make up for those lost

Floodplains Floodplains are Low lands along

riverbanks, lakes, and coastlines that are subjected to periodic inundation.

Human have begun developing on floodplains

Has caused disruption in the ecosystem

Ecosystem Management Integration of ecological, political, and

social goals to try to solve the environmental problems

Goals: All levels of the environment must be managed Stop political boundaries Routine data collection Adaptive management Humans in nature Organizational change Values

Works Cited Cunningham, William P., Mary Ann Cunningham,

and Barbara Woodworth Saigo. Environmental Science a Global Concern. 9th ed. New York: McGraw, 2007. Print.

http://auth.mhhe.com/biosci/pae/environmentalscience/olc_linkedcontent/cunningham06es/cs6_15.htm

http://auth.mhhe.com/biosci/pae/environmentalscience/olc_linkedcontent/cunningham06es/cs6_05.htm

http://www.fws.gov/Refuges/