Forest Resources Types of timber harvesting & sustainable management

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 world’s forest High biodiversity

Second-growth forest:  Area which has re-grown after a major disturbance such as fire, insect, or timber harvest  60% of world’s forest  Happens by natural “succession” -s mall shrubs and trees followed by the larger trees 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 Forests Vary in Their Make-up, Age, and Origins

What are forests good for? Estimated annual value: Economic services $1.8 trillion Ecological services $4.7 trillion

 Three major tree harvesting methods: Selective cutting Clear-cutting Strip cutting Seed tree/shelterwood How are trees cut?

 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 Selective cutting

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

Clear-cutting Clear-cutting

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

Other ways forests can be destroyed  Forest fire  Insect damage (mountain pine beetle in BC)  Disease (Dutch elm disease in Ottawa)

 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 Fire Can Threaten Forest Ecosystems

 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 Forest fires continued

Insect damage

Issues in forestry  Human activities have reduced the earth’s 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

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.

We Have Cut Down Almost Half of the World’s Forests

 Poor soil in tropical forests  Run-off  Not much can grow after gain Tropical Forests Are Disappearing Rapidly

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