• Transform an area from forested to non- forested – Logging – Land clearing • Urban • Agricultural •Mining
Old growth forests • Multi-aged forest with large, very old trees (100+ years), younger trees (although generally not very young), fallen timber, and underbrush. • Forest regenerated after disturbance (fire, logging) is generally called second-growth until it has again acquired old-growth characteristics • Old growth forests are desirable to loggers because of the size of logs and tree species – Logging old growth forests very contentious – Old growth forests home to rare, threatened and endangered species: Northern Spotted Owl
1 Disruptions in a biome/ecosystem • Corridors and patches: a break or cut in an area, does not contain the normal type of vegetation • Species may need a continuous cover of fauna to live
Deforestation • Tree removal reduces the production of oxygen released into the atmosphere • Also releases carbon into the atmosphere (as carbon dioxide or methane) • Logging or land clearing often involves burning an area – also release CO2 • Disturbs the habitat and ecosystem
Logging • In US, old growth forests logged in 1800s and early 1900s • Trees cut and land left to recover on its own – "cut-out and get-out" philosophy • Traditional logging very invasive and destructive on the land – Access roads compact soil – Refuse piles – Soil erosion
2 Logging
Clear cutting
• All trees removed in an area • Creates a patchwork effect • Meant to save some areas for animal habitat while harvesting the wood
3 Clear cutting
• May be good for some tree species that need sunlight to grow • All new trees in area now same age and same species – Increased susceptibility to disease, fire and insects • Increased erosion and flooding • Loss of nutrients
Low-impact logging
• Also called “reduced-impact”, “sustainable” or “gentle logging” • Take some of the trees – leaves some trees • Methods differ but usually seek to: – Minimize damage to the residual stand – Minimize impact to land – Minimize erosion
4 Low-impact logging
• Selective cutting of trees – age and location – Maintains diverse forest for resident flora and fauna – Resists disease and fire – Reduces erosion • Smaller scale equipment
US Logging
• Private and public (USFS) lands – Private lands – may have old-growth forests or tree farms • Harvesting methods differ • After harvested, area replanted – Public lands – a lot more old-growth forests • Very cheap for forest companies to log on public lands • Government sells logging rights very cheaply • Land then replanted – typically clear cut
Post-logging: tree farms • Privately owned managed forest used for timber production • Actively started in 1940’s – Fears of a “timber famine” – Trees were being cut at an unsustainable rate • Movement away from the "cut-out and get-out" philosophy
5 Post-logging: tree farms
• First official tree farm in Washington state • Today – very productive – California has 600+ tree farms – Can have tree farms for specific species – Not just for Christmas trees • Idea is to have several stands of different ages so harvesting is staggered – Can, in some instances, just plant and walk away for several years
Tree farm drawbacks
• Not natural – Usually only 1 species – limits fauna – Susceptible to disease and fire • Better than harvesting old-growth forests
6 Deforestation in other parts of developed world • Most of Europe no longer has any old- growth forest • Tree farming extensive and well-managed • Japan – wood shortage • Canada – extensive logging of old-growth forests
Tropical rainforest clearing
• Approximately 1% of tropical rainforest lost each year – Logging • Some regeneration now –Agricultural • Crops: coffee, bananas, rubber trees • Pasture: cattle • Central America – ½ rainforest remains
Rainforest clearing
• Soil quality quickly diminishes • Road construction to access logging sites opens area up to occupation • Loss of species tremendous
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