Forest Resources

Clear Cutting

• forest harvesting that removes all trees from an area.

• Includes desirable AND undesirable species

• the land is left uncovered.

Clear Cutting

Disadvantages – Leaves behind

a poor looking landscape.

– impossible to duplicate the biodiversity of forest.

– Soil is defenseless to erosion.

– Wildlife habitats are disturbed.

Advantages fastermore economical and least dangerous

Clear Cutting

Selective Cutting

• harvesting that removes only mature trees and leaves the other trees in place. 

• Immature trees, undesired species and underbrush is all left intact. 

Selective Cutting

Disadvantages Most expensive method. Yields are lower. Care must be taken to avoid damaging unharvested trees. Roads must be maintained longer to keep harvesting

mature trees.

Advantages Leaves the biggest portion of the forest intact. Causes the least ecological disruption.

Deforestation – p. 163• The removal of a forest stand by cutting and/or burning,

• the land is put to a non-forest use…

• Ex. agricultural purposes, residential or industrial sites, roads, etc..

Deforestation

Some values of our worlds forests are:

• biodiversity• medicine/pharmaceuticals- animal habitats- air purification- water retention- soil maintenance

• Forests can be used for things like:

- building materials- home heat- recreation - paper.

Approx. 1/3 of the earth's land masses are covered in forest.

Deforestation – Reasons!?!?

Reasons for extensive deforestation include:

• Expanding needs in agriculture (#1)

• Urbanization

• Mining operations

• Hydroelectric operations - flooding the land

• Logging, lumber, building materials

“Rates of Deforestation World Wide” (pg.164)

Deforestation - Latin America

• clearing the forests for hydroelectric projects to provide electricity to an increasing number of people.

• Large scale cattle ranches and urbanization have also contributed to deforestation.

• The cost of “modernization”!!!!

Deforestation - Latin America

Deforestation - Africa • forests are being cleared to make room for subsistence

farming to support the growing & hungry population.

Deforestation – Asia• A growing population means that more forest is cleared for

housing and for agricultural land to feed the people.

Sustainable Forestry

• Sustainable means to manage or maintain something so that it remains and provides benefits over the LONG term.

• Sustainable forestry… is a method of harvesting or using the forests so that the resource is not depleted or permanently damaged.

FACT• If we cut trees faster than they

grow back, we will run out of trees.

• However, as the world's population increases, the demand for forestry products increases and the demand for forestry land to be converted to housing, mining, and hydro-electricity projects.

• We must manage the forest, taking into consideration biodiversity, hunting, hiking, camping, habitat protection and many other things.

Sustainable ForestryFrom a “Systems Model” perspective:

1. Improve what we input into forestry (replanting & seeds)

2. Improve processes like: o road construction o harvesting techniques o environmental protection actions o reducing losses (use all of the tree)

3. Reduce the need of output product o Recycle o Use of alternate building materials

Clear Cutting Controversy

(handout)

Forests and ClimateSeasons

• The type of trees and forest present in a region is determined by the climate. 

• Trees have adapted to climate just as animals have.

• Temperate regions of the world often have broad-leaf, deciduous trees to help them deal with the lack of water availability in winter. (ex: lose leaves so moisture does not freeze). 

• Some regions have dry seasons and they have deciduous trees even though it does not get "cold."

Seasons• The needle leaf trees of the coniferous

forests are adapted to deal with winter and the lack of available water. (ex: tall and narrow, grow close together, waxy coating on needles)

• Both the tropical regions of the world and the sub arctic regions of the world have evergreen trees.

Forests and Climate

Precipitation

• Forests require a large amount of water. Therefore, the amount of precipitation in a region will determine whether a forest will grow.

• Tropical areas with high rainfall have tropical rain forests (meaning lots of trees/vegetation). Tropical areas that have alternating rainfall amounts have Savannas because there is not enough water to support trees and a forest. 

Forests and Climate

Diversity

• Colder regions tend to have less biodiversity while tropical regions tend to have greater biodiversity. 

• The same is true of trees. Tropical forests tend to be a blend of many different species, while coniferous forests tend to be "pure stands" of one type of tree.

Case Study• “Tree Harvesting in Various

Ecosystems”• Pg. 166• Question #9