Forest Resources

1
Forest Resources

• Types of timber harvesting sustainable
  management

2
What types of forests are there?

• Old-growth forest Original forests that have not
  been disturbed for logging, road building, or
  development
• Sometimes called primary, ancient, virgin, or
  primeval forests
• 36 of worlds forest
• High biodiversity

3
Forests Vary in Their Make-up, Age, and Origins

• Second-growth forest
• Area which has re-grown after a major disturbance
  such as fire, insect, or timber harvest
• 60 of worlds forest
• Happens by natural succession -small shrubs and
  trees followed by the larger trees

4
Forests Vary in Their Make-up, Age, and Origins

• Tree plantation (tree farm)
• Planted stands of a particular tree species that
  are maintained, harvested, and replanted
• Typically used for paper or particle board

5
What are forests good for?
Estimated annual value Economic
services 1.8 trillion Ecological services 4.7
trillion
6
How are trees cut?

• Three major tree harvesting methods
• Selective cutting
• Clear-cutting
• Strip cutting
• Seed tree/shelterwood

7
Selective cutting

• Selective Cutting
• Mature trees are harvested individually from
  diverse forests
• Younger trees left to harvest later
• Reduces crowding
• Removes diseased trees
• Encourages growth of younger trees

8
Clear-cutting

• Clear-cutting
• Removing all trees in a single pass.

9
Clear-cutting
Clear-cutting
10
Strip-cutting

• Strip-cutting
• A type of clear cutting that involves clear
  trees along the contours of the land.
• Less erosion

11
Other ways forests can be destroyed

• Forest fire
• Insect damage (mountain pine beetle in BC)
• Disease (Dutch elm disease in Ottawa)

12
Fire Can Threaten Forest Ecosystems

• Forest fires can either benefit or harm forests
• Burn away flammable ground material
• Prevent larger, more destructive fires
• Release valuable mineral nutrients
• Stimulate new forest growth

13
Forest fires continued

• Surface fires
• Usually burn leaf litter and undergrowth
• May provide food in the form of vegetation that
  sprouts after fire
• Crown fires
• Extremely hot, burns whole trees, jump from
  treetop to treetop
• Fierce and hard to control

14
Insect damage
15
Issues in forestry

• Human activities have reduced the earths forest
  cover by as much as half.
• Deforestation temporary or permanent removal of
  large areas of forests
• Results from unsustainable cutting of trees
• Where is deforestation an issue?
• Developing countries used for fuel, wood in
  tropical forests used by international logging
  companies
• Developed countries boreal forests used for
  timber and paper

16
Unsustainable Logging is a Major Threat to
Forest Ecosystems

• Building roads into previously inaccessible
  forests paves the way for increased erosion,
  habitat fragmentation, loss of biodiversity, and
  invasion by non-native species.
• For this reason, many federal wilderness areas do
  not allow the construction of roads.

17
We Have Cut Down Almost Half of the Worlds
Forests
18
Tropical Forests Are Disappearing Rapidly

• Poor soil in tropical forests
• Run-off
• Not much can grow after gain

19
Are there solutions?

• We can use forests more sustainably by
  emphasizing
• Economic value of ecological services
• Harvesting trees no faster than they are
  replenished
• Protecting old-growth and vulnerable areas