Forest Ecosystem and Management

Forest Make-up Forests cover about 30% of the Earth’s land surface (natural and planted) Old-growth or primary forest (36%) Uncut, or not disturbed for several hundred years Reservoirs of biodiversity E.g. Redwood Forest Second-growth forest (60%) Secondary ecological succession Tree plantation, (tree farm, commercial forest) (4%) May supply most industrial wood in the future

Tress Plantation Usually monoculture in species e.g. Apple orchard, Jack Pine Reforestation in Mio, MI

Rotation of Cutting and Regrowth of a monoculture tree plantation Weak trees removed 25 yrs Clear cut 30 yrs 15 yrs Years of growth Seedlings planted 5 yrs 10 yrs

Ecological and Economic Services Support energy flow and chemical cycling Habitats Wood for fuel Reduce soil erosion Lumber Absorb and release water Pulp to make paper Purify water and air Mining Influence local and regional climate Livestock grazing Recreation Store atmospheric carbon Employment

Ecological Services The ecological services that the world’s forests provides is worth at least $4.7 trillion per year. This is hundreds of times more worth than their economic value.

Economic Value of Ecological Services

Unsustainable Logging Threats Increase erosion Sediment runoff into waterways Habitat fragmentation Loss of biodiversity Invasion by: Nonnative pests Disease Wildlife species

Building Roads into Forests New highway Old growth

Building Roads into Forests Highway Cleared plots for grazing Cleared plots for agriculture

Building Roads into Forests

Major Harvesting Methods Selective Cutting Clear-cutting Strip- cutting

Selective Cutting Clear stream

Clear Cutting Muddy stream

Strip Cutting Uncut Cut 1 year ago Dirt road Cut 3–10 years ago Uncut Clear stream

Clear-Cutting Trade-offs Advantages Disadvantages High timber yields Reduces biodiversity Maximum profits in short time Destroys and fragments wildlife habitats Can reforest with fast growing trees Increases water pollution, flooding, and erosion on steep slopes Good for tree species that need full or moderate sunlight Eliminates most recreation value

Threats to 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 Kill wildlife Increase soil erosion

Surface and Crown Fires

Threats to Forest Ecosystems Introduction of foreign diseases and insects Accidental Deliberate Global warming Rising temperatures Trees more susceptible to diseases and pests Drier forests: more fires More greenhouse gases

Nonnative Species and Disease Organisms in the U.S. Forests

Deforestation Deforestation Tropical forests Especially in Latin America, Indonesia, and Africa Boreal forests Especially in Alaska, Canada, Scandinavia, and Russia Net total forest cover has stayed the same or increased in U.S. and a few other countries between 2000 and 2007

United States Forest have Grown Back Forests of the eastern United States decimated between 1620 and 1920 Grown back naturally through secondary ecological succession in the eastern states Biologically simplified tree plantations reduce biodiversity and deplete nutrients from soil