AP Environmental Science Ch. 10, part 1 Miller LITE
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Forests
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AP Environmental Science Ch. 10, part 1 Miller LITE
- 1. Sustaining Terrestrial Biodiversity: The Ecosystem Approach Ch. 10, part 1: Forests
- 2. An outline for this lecture I. Forests I. Types II. Locations III. Services IV. Logging I. solutions V. Fire I. solutions VI. Invasive species/disease I. solutions VII. Climate change VIII. Deforestation IX. Tropical forest issues Quick thinkQuick think Quick thinkQuick think Quick thinkQuick think Quick thinkQuick think
- 3. The Big Idea • There is no solution, I assure you, to save Earth’s biodiversity other than preservation of natural environments in reserves large enough to maintain wild populations sustainably. - E. O. Wilson
- 4. Types of Forests • Forests take up about 30% of the Earth’s surface
- 5. 2 major types of forests 1. Old Growth Forests: o aka primary forests o ~36% of all forests o Uncut o not seriously disturbed by people for at least 200 years o Reservoirs of biodiversity
- 6. 2 major types of forests 2. Second growth forests • a result of secondary succession • ~60 % of all forests
- 7. Also…tree plantations • Aka tree farm or commercial forest • ~4 % of all forests • Managed area • Usually only 1 or 2 species or tree • Grow trees, harvest by clear cut, grow again, etc • Can produce a lot of wood quickly • Used mostly for paper
- 8. But… • Tree farms deplete the soil of nutrients • Much less biodiversity • Often genetically modified trees are grown --> controversial
- 9. Where are the old growth forests? • Russia • Canada • Brazil • Indonesia • Papua New Guinea Have 75% of the remaining old growth forests
- 10. Where are the tree farms? • China (almost no original forests) • India • USA • Russia • Canada • Sweden Have 60% of the tree farms
- 11. Where are the old growth forests?
- 12. Ecosystem Services The processes by which the environment produces resources used by humans such as clean air, water, food and materials
- 13. Forest Services • Energy flow • Recycle nutrients • Important in water cycle • Purify water and air • Influence local climate • Remove CO2 from air • Diverse habitats for wildlife (2/3 of all land species!) • Wood for fuel • Lumber • Paper • Mining • Livestock grazing • Recreation • Jobs (25% of jobs) • Medicines (tropical plants = new drugs)
- 14. Quick Think 1 What major ecologicalecological and economiceconomic benefits do forests provide? How do these benefits vary between oldold growthgrowth, 22ndnd growthgrowth, and tree farm foreststree farm forests?
- 15. Logging• Step 1 - build roads to get to the trees – Soil erodes off roads and ends up in waterways – Roads fragment habitat – Increases risk of invasion by nonnative species, diseases – Makes once inaccessible areas open to hunters, miners, ranchers
- 16. Logging • Step 2 - cut the trees – Selective cutting - middle aged or old trees selectively cut • Slower, more costly – Clear cut - all trees in an area cut • Faster, more efficient, more wood • Increase erosion & runoff • Depletes nutrients from soil • Benefits tree species that need more light to grow • Eliminates recreational value for most
- 17. Logging in developing nations • Often done illegally • 70 countries - mostly in Africa and Southeast Asia • In Kenya, 37 out of 41 national parks destroyed • In Indonesia, ~75% of all logging illegal • Why? DEMAND Illegal logging camp in Kenya
- 18. What to do 1. Manage the forest more sustainably with selective cutting (but expect to pay more) 2. Certify wood as sustainably grown…take advantage of the green movement Strip cuttingStrip cutting
- 19. We can reduce demand for wood • Excess packaging & junk mail
- 20. We can use other sources for paper • China uses rice straw • Most of tree-free paper in USA comes from kenaf
- 21. Quick Think 2 Distinguish among selective cutting, clear cutting, and strip cutting in the harvesting of trees. AND What are the advantages and disadvantages of clear-cutting forests? As a consumer – how would more selective cutting affect prices of domestic goods?
- 22. Fire! • Surface fire – Burns undergrowth and leaf litter – Small trees die, mature trees and most animals survive – Can be beneficial • Prevents major fires • Help some plant species seeds germinate • Deer, moose, quail need fires to maintain their habitat Lodgepole pine
- 23. Fire! • Crown fire – Very hot – Burns whole trees – In forests that haven’t had fires in a long time – Very damaging, kills wildlife, erodes soil, destroys most plants
- 24. We can control fire • Prescribed fires • Goats to clear undergrowth (in CA) • Let ‘em burn…(as long as now structures or people are in danger)
- 25. Invasive Species & Disease • Accidental (or deliberate) introduction - a major threat to forests everywhere
- 26. Others White pine blister rust Beech bark disease Pine shoot beetle HemlockHemlock woolly adelgidwoolly adelgid
- 27. How to help • Ban imported timber • Remove infested trees • Use genetic engineering to develop resistant trees • Control pests with pesticides • Biological control + pesticides (but less)
- 28. Quick Think 3 What are some ecological benefits to the occasional surface fire? AND Of all the ways to reduce the impact of disease/invasive species, which one is likely best for the forest and why?
- 30. Climate change • Many trees are sensitive to heat – Sugar maple • No maple syrup! – Insects/disease like heat – Dry forests = fire = even more CO2
- 31. Deforestation • Decreased soil fertility • Runoff pollutes water • Extinction of species with specialized niches • Loss of habitat for natives and migratory birds and butterflies • Local climate change • Extra CO2 in atmosphere • More flooding
- 32. The Deal with Tropical Forests • Most loss has occurred after 1950. • Mostly illegal logging – 75% of the logging industry in Indonesia from illegal operations – Already 72% of forests gone, by 2022 98% of what is left will be gone – Logging for timber, cattle ranching, soybean crops Indonesia highest in biodiversity
- 34. How trees are cut in the rainforest 1. Clear a road in 2. Set up camp 3. Selectively remove best trees 1. Smaller trees fall with them due to vines and shallow roots
- 35. Big Companies • Foreign companies hold most of the contracts with the gov’t for the timber • Once the forests are depleted, the company moves to another country, leaving the mess behind – E.g Phillipines – most hardwood forests gone, now they must import most of their wood
- 36. Quick Think 4 1. Identify the major threats to forests (there are 5) 2. Identify at least 1 thing that can be done to mitigate the threat 3. Identify at least 1 thing you can personally do 4. Identify at least 1 thing that would require government or business control
- 37. • http://www.pbs.org/frontlineworld/rough/2008/0 What are carbon offsets and how are they being used in this case?