1. Forests: Resources and degradation

2. Interesting……… Number of trees growing in N. American is the same as 100 years ago, but only 5% original forests left……. Deforestation Removal of trees for lumber or agricultural purposes Deforestation is more common in developing countries, yet they have a lower demand for wood. Why? Mostly due to developing nations need space to grow food!

3. N. America deforestation Occurs to create space for homes/agricultural plots

4. Deforestation Clearing of trees without replacing them Driving forces– increased populations of given area 1. Demand for new farmland 2. Demand for wood- products (lumber for homes, paper, furniture) 3. Make space for roads, factories, offices, homes

5. Plants are gone? What’s the big deal? WHAT (specifically) environmental impacts can arise if natural flora of a region are gone? Loss of biodiversity (plat and animal)– due to habitat destruction Increased soil surface temperature– kills seedlings/sprouting plants Without new plants growing/dying– leaf litter decreases, blocking the natural flow of organic matter entering the soil Dehydration of soil due to sunlight exposure Soil become compacted- does not allow air/water to absorb into roots and soil Soil run-off– soil not anchored by plants can be carried quickly to lowland areas causing flooding/clogging natural streams

6. Rain forest deforestation Soil in rainforest is very poor, but still being cut down 1.5 acres/second! Cleared for agricultural land, but doesn’t last long b/c of is poor quality. More must be cut

7. Tropical Rainforest Deforestation Amazon Rainforest 1.7 billion acres Largest and most species rich rainforest in the world.

8. Red/pale areas– deforested Since 1970– 91% of all deforested areas used for one thing– guess?? Livestock pasture

10. Which land clearing technique is being used? Clear cutting Benefits?

11. Clear cutting Advantages/disadvantages Advantages Quick economic/monetary value High timber yields Disadvantages Destroys wildlife/biodiveristy Increases erosion/flooding Any other listed on previous slide

12. Slash and burn– cut it all down, burn Increases CO2/ greenhouse gas levels

13. Amazon Farmers must move from one plot of land to another quickly--why? Brazil (60% of entire forest)—2 nd largest soybean producers in the world Soil in rainforest is not fertile– all nutrients of forest is located in the trees/plants themselves

14. Types of forests Old-growth– uncut forest or regenerated that has not been disturbed by humans/natural disasters for 200 years or more Secondary-growth– resulting from secondary succession Caused by: Humans cutting down trees Natural disasters—fire, hurricanes, volcanoes Tree farm– farm with one or two genetically identical trees cut down as soon as they are economically valuable BUT- trees farms less biodiverse and cycle of cutting/replanting can eventually deplete soil of nutrients over time

15. Benefits from trees Tree farming properly is important b/c as human pop increases—more paper, lumber for homes, wood for furniture needed Trees sequester CO2 from atmosphere

16. Silviculture– management of forest plantations for timber Goal: to harvest trees sustainably—cut down only what you can plant

17. Harvesting Techniques Clear-cutting– cutting down all trees in a given area Cheaper, quicker– much more environmentally devastating Better alternatives Selective-cutting– removing only mature/middle aged trees Leaves major habitat in place and eco-impact Keeps biodiversity Practice known as uneven-aged management Strip cutting-clear cutting in strips along contour of land Allows natural regeneration to occur Then loggers cut another strip

18. Old-growth forest

19. Tree Farm

20. Clear cutting

21. Selective cutting

22. Strip cutting

23. Forest Fires Fires can also affect forest ecosystems: Surface fire– only undergrowth burns Forest floor, leaf litter Kills seedlings, but spares mature trees and most animals Crown fire– extremely hot fire Start on ground burns from treetop to treetop or “crown” of trees Usually occur in forests going years w/o surface fires HUGE THREAT to homes,people, wildlife Ground fire– burn underground Usually in swamps/bogs—can burn for several weeks

24. Surface fire

25. Ground fire

26. Crown fires

27. Fires are important Some tree species (pine trees in NJ) rely on fire as their natural life cycle Fires burn every few years and keep fuel levels on ground low (leaf litter, dead trees) If no fires, fuel levels build HUGE fire can result—very hard to control, can be very destructive Many parks implement “controlled burns” to prevent this

28. Smokey the bear

29. Protection/management of forests Gov. own nearly 35% of all land in US National park system Created to manage/preserve forests and grasslands Many national parks being threatened by degradation of offroad vehicles, pollution, invasives, poaching i.e. Gray Wolf– Yellowstone National Park Wilderness Preservation Areas —open only for recreational activities—no logging allowed. National Forest System, Natural Resource Lands, National Wildlife Refuges all control areas—cannot log w/o permit

30. Laws Wilderness Act (1963) reviews of road free areas larger than 5000 acres within National Wildlife Refuges and National Park System—helps preserve these areas Wild and Scenic Rivers Act—protects rivers for importance of scenic, recreational, fish and wildlife values.

31. Goals of National Park System Setup to sustain and manage: Scientific/educational purposes Serve as a reservoir for natural gene pools of different plants and animals Ties in with biodiversity Recreation use (fishing, hunting, bird watching) Aesthetic use (sightseeing)

32. Yellowstone National Park First national park found in 1872 Ironically– park was initially founded for preserve: timber resources Mineral resources Not until 1960– national parks were created for ecosystem and biodiversity preservation

33. Yellowstone National Park 3,468 sq. miles New Jersey 8,721 sq. miles USA (continental USA) 3,119,884.69 square miles

34. Yellowstone National Park Has a range of ecosystems– mountains, grasslands, canyons, rivers, lakes Yellowstone Lake Old Faithful

36. Yellowstone super volcano http://www.youtube.com/watch?v=1Vn6kxfD3Ek

37. Greenbelts Areas of land built on the outer edge of a city/development Used for recreation, sustainable forestry, site seeing (anything else non-destructive) These help limit the boundaries of urban sprawl/development

38. England greenbelt

39. NYC Central Park

40. Grassland sustainability Grasslands have significant biological importance: Soil formation Erosion control CO2 sequestering Nutrient cycling FUN FACT: Why does grass continue to grow after you cut it, but a tree does not? Ans: b/c grass grows from the base, not the tip!

41. Livestock grazing Rangeland– unfenced grasslands used for livestock grazing Pasture—enclosed meadows planted with planted grasses Grazing is a sustainable practice if managed correctly Overgrazing– more grass consumed by animals faster than it can re-grow Leads to erosion, soil compaction ANIMAL WASTE—leeches into water ways causes massive amounts of pollution Rangeland animals for slaughter consume 70% of US total grain crop

43. Overgrazing In some cases, rangeland is overgrazed Too many animals are grazing in area that range cannot support This tends to affect plant communites/ecology Too many plants are eaten, land becomes degraded A less-desirable plant species may replace a more desirable species Most extreme cases– all plants are eaten What are some possible environmental impacts of all plant species being eaten?

44. Plants are vital to keeping natural, healthy ecosystems within the rangeland Once all plants are eaten, rangeland becomes vast/barren Solutions—rotate animals from site-to-site, control numbers of animals in herd

45. Manage and sustain grasslands Rotational grazing

46. Some USDA info Horse must eat 1.5% of its body weight in dry forage 1,000lb. Horse needs 2,700 lbs of forage in 6month grazing season 3-5 acres for one horse BUT using rotational grazing…… On moderately productive soils, can use 2 acres for 7-8 months