Ecosystem Approach: Variation of Forests 
Chapter 9: Ecosystem Approach
Variation of Forests in Their Age, Makeup, and Origins
A. 2 Major Types of Natural Forests
1. Old-growth/ Primary
-uncut/ regenerated forest that has not been seriously disturbed by human activities/ natural disasters for 200 years or more
- reservoirs of biodiversity (provide ecological niches for a variety of wildlife species)
2. Second- growth
- stand of trees resulting from secondary ecological succession
B. Tree Plantation/ Tree Farm/ Commercial Forest
-managed forest containing one or two species of trees that are all of the same age
-could supply most of wood
-less biologically diverse ( one or two only)
- less sustainable
Economic and Ecological Services of Forest
-Remove Carbon dioxide through photosynthesis
- Provide habitats of 2/3 of Earth’s terrestrial species
- Shelter for humans
Threats to Forest Ecosystems
I. Unsustainable Logging
A. 3 Ways of Harvesting Trees
1. Selective Cutting
- intermediate- aged or mature trees in forests are cut singly or in small groups
2.Clear Cutting
- most efficient
- cuts all trees
3. Strip Cutting
- involves clear- cutting a strip of trees along the contour of the land within a corridor narrow enough to allow natural forest regeneration within a few years
II. Forest Fires
A. 2 Types of Fires
1. Surface fires
-usually burn only undergrowth and leaf litter on the forest floor
2. Crown fire
- extremely hot fire that leaps from treetop to treetop, burning whole trees.
- usually occur in forests that have not experienced surface fires for several decades, a situation that allows dead wood, leaves and other flammable ground litter to accumulate
III. Deforestation * Is the temporary or permanent removal of large expanses of forests for agriculture, settlements, or other uses.
Rapid Disappearance of Tropical Forests
Tropical Forests * Cover about 6% of Earth’s land area * Being cut rapidly in parts of Africa, Southeast Asia,
Variation of Forests in Their Age, Makeup, and Origins
A. 2 Major Types of Natural Forests
1. Old-growth/ Primary
-uncut/ regenerated forest that has not been seriously disturbed by human activities/ natural disasters for 200 years or more
- reservoirs of biodiversity (provide ecological niches for a variety of wildlife species)
2. Second- growth
- stand of trees resulting from secondary ecological succession
B. Tree Plantation/ Tree Farm/ Commercial Forest
-managed forest containing one or two species of trees that are all of the same age
-could supply most of wood
-less biologically diverse ( one or two only)
- less sustainable
Economic and Ecological Services of Forest
-Remove Carbon dioxide through photosynthesis
- Provide habitats of 2/3 of Earth’s terrestrial species
- Shelter for humans
Threats to Forest Ecosystems
I. Unsustainable Logging
A. 3 Ways of Harvesting Trees
1. Selective Cutting
- intermediate- aged or mature trees in forests are cut singly or in small groups
2.Clear Cutting
- most efficient
- cuts all trees
3. Strip Cutting
- involves clear- cutting a strip of trees along the contour of the land within a corridor narrow enough to allow natural forest regeneration within a few years
II. Forest Fires
A. 2 Types of Fires
1. Surface fires
-usually burn only undergrowth and leaf litter on the forest floor
2. Crown fire
- extremely hot fire that leaps from treetop to treetop, burning whole trees.
- usually occur in forests that have not experienced surface fires for several decades, a situation that allows dead wood, leaves and other flammable ground litter to accumulate
III. Deforestation * Is the temporary or permanent removal of large expanses of forests for agriculture, settlements, or other uses.
Rapid Disappearance of Tropical Forests
Tropical Forests * Cover about 6% of Earth’s land area * Being cut rapidly in parts of Africa, Southeast Asia,