land
DESCRIPTION
Land. What’s on it? How can we use the resources?. Land use, million acres. ?????. ???. Public lands controversies. More common in the west that’s where the public land is!. What should be done with/on public lands?. Nothing: enjoy the wilderness Preserve specific species - PowerPoint PPT PresentationTRANSCRIPT
![Page 1: Land](https://reader036.vdocument.in/reader036/viewer/2022070418/56815915550346895dc63faf/html5/thumbnails/1.jpg)
Land
What’s on it?
How can we use the resources?
![Page 2: Land](https://reader036.vdocument.in/reader036/viewer/2022070418/56815915550346895dc63faf/html5/thumbnails/2.jpg)
Land use, million acres
Land Use in the U.S.
587
651
44260
228
297
Cropland
Grassland
Forest
Special
Miscellaneous
Urban
![Page 3: Land](https://reader036.vdocument.in/reader036/viewer/2022070418/56815915550346895dc63faf/html5/thumbnails/3.jpg)
Figure 12.6
![Page 4: Land](https://reader036.vdocument.in/reader036/viewer/2022070418/56815915550346895dc63faf/html5/thumbnails/4.jpg)
?????Figure 12.14
![Page 5: Land](https://reader036.vdocument.in/reader036/viewer/2022070418/56815915550346895dc63faf/html5/thumbnails/5.jpg)
???Figure 12.15
![Page 6: Land](https://reader036.vdocument.in/reader036/viewer/2022070418/56815915550346895dc63faf/html5/thumbnails/6.jpg)
•
![Page 7: Land](https://reader036.vdocument.in/reader036/viewer/2022070418/56815915550346895dc63faf/html5/thumbnails/7.jpg)
Public lands controversies
• More common in the westthat’s where the public land is!
![Page 8: Land](https://reader036.vdocument.in/reader036/viewer/2022070418/56815915550346895dc63faf/html5/thumbnails/8.jpg)
What should be done with/on public lands?
• Nothing: enjoy the wilderness• Preserve specific species• Preserve biodiversity generally• Extract resources: timber, minerals, fossil
fuels, wildlife (hunting), forage (grazing)• Recreation• Manage for ecosystem services: flood
control, carbon storage, etc.
![Page 9: Land](https://reader036.vdocument.in/reader036/viewer/2022070418/56815915550346895dc63faf/html5/thumbnails/9.jpg)
![Page 10: Land](https://reader036.vdocument.in/reader036/viewer/2022070418/56815915550346895dc63faf/html5/thumbnails/10.jpg)
Natural resources
• Timber
• Minerals – key to modern technological society– Where come from?
• Mining
• Recycling
What is a key difference between timber and minerals?
![Page 11: Land](https://reader036.vdocument.in/reader036/viewer/2022070418/56815915550346895dc63faf/html5/thumbnails/11.jpg)
Natural resources
• Soils
• Wildlife
• Rangeland
• Water
• Fossil fuels
![Page 12: Land](https://reader036.vdocument.in/reader036/viewer/2022070418/56815915550346895dc63faf/html5/thumbnails/12.jpg)
FORESTS
• Can they be managed sustainably?– What does this mean?
• Harvesting a renewable resource in such a way that harvesting can continue indefinitely.
Think of this as having a bank account and only using (harvesting) the interest or growth each year.
![Page 13: Land](https://reader036.vdocument.in/reader036/viewer/2022070418/56815915550346895dc63faf/html5/thumbnails/13.jpg)
Maximum sustained yield
• A tool for managing timber and other resources
• Achieve maximum resource extraction without depleting resource from one harvest to another
![Page 14: Land](https://reader036.vdocument.in/reader036/viewer/2022070418/56815915550346895dc63faf/html5/thumbnails/14.jpg)
Figure 12.2
• Managers trying for MSY prefer to keep the population at intermediate sizes, because that is where growth rate is fastest.
![Page 15: Land](https://reader036.vdocument.in/reader036/viewer/2022070418/56815915550346895dc63faf/html5/thumbnails/15.jpg)
Problems with MSY• Natural populations rarely follow logistic curve.• Requires harvesting at about half the carrying
capacity, BUT how know what the carrying capacity is? Is carrying capacity a fixed size?
• May yield the best harvest, but may reduce the resource below a level that is good for the ecosystem
• With trees, cutting them when they are growing fast = young trees. What about species that like mature trees for habitat?
• Is the environment constant?
![Page 16: Land](https://reader036.vdocument.in/reader036/viewer/2022070418/56815915550346895dc63faf/html5/thumbnails/16.jpg)
Figure 12.6
![Page 17: Land](https://reader036.vdocument.in/reader036/viewer/2022070418/56815915550346895dc63faf/html5/thumbnails/17.jpg)
What kind of forests are there?
• Virgin timber: never been logged
• Old growth: another name for virgin forest, but less precise. Generally: big, old trees– Near limit of life-span and size
• Second-growth: a forest that has been cut and regrown
![Page 18: Land](https://reader036.vdocument.in/reader036/viewer/2022070418/56815915550346895dc63faf/html5/thumbnails/18.jpg)
Old-growth
•
![Page 19: Land](https://reader036.vdocument.in/reader036/viewer/2022070418/56815915550346895dc63faf/html5/thumbnails/19.jpg)
Loblolly pine: which is old-growth, which second-growth?
•
![Page 20: Land](https://reader036.vdocument.in/reader036/viewer/2022070418/56815915550346895dc63faf/html5/thumbnails/20.jpg)
Pine plantation
•
![Page 21: Land](https://reader036.vdocument.in/reader036/viewer/2022070418/56815915550346895dc63faf/html5/thumbnails/21.jpg)
How are wild stands logged?
• Clear cuttingBritish Columbia
Everything cut.
Replanted area ends up even-aged.
![Page 22: Land](https://reader036.vdocument.in/reader036/viewer/2022070418/56815915550346895dc63faf/html5/thumbnails/22.jpg)
How are wild stands logged
• Shelterwood• Stand cleared of most
trees, leaving a few young, healthy trees.
• For pines to the right, the understory is burned, killing competition and prepping soil for seeds.
• No seedlings need be purchased or planted.
• Similar to seed-tree cutting.
![Page 23: Land](https://reader036.vdocument.in/reader036/viewer/2022070418/56815915550346895dc63faf/html5/thumbnails/23.jpg)
How are wild stands logged?
• Selective cuttingA few high-value trees are
taken at one time, with most trees left standing.
In British Columbia and elsewhere, logging impact reduced by using helicopters.
![Page 24: Land](https://reader036.vdocument.in/reader036/viewer/2022070418/56815915550346895dc63faf/html5/thumbnails/24.jpg)
Logging along roads, Amazon
•
![Page 25: Land](https://reader036.vdocument.in/reader036/viewer/2022070418/56815915550346895dc63faf/html5/thumbnails/25.jpg)
Logging along roads, Amazon
• False color• Red – old growth• Orange - second
growth• Blue/white -
deforested
![Page 26: Land](https://reader036.vdocument.in/reader036/viewer/2022070418/56815915550346895dc63faf/html5/thumbnails/26.jpg)
What covers the earth?
• Forests: about 30% of Earth’s land surface– 56% tropical or subtropical– 44% temperate or boreal
![Page 27: Land](https://reader036.vdocument.in/reader036/viewer/2022070418/56815915550346895dc63faf/html5/thumbnails/27.jpg)
•
![Page 28: Land](https://reader036.vdocument.in/reader036/viewer/2022070418/56815915550346895dc63faf/html5/thumbnails/28.jpg)
![Page 29: Land](https://reader036.vdocument.in/reader036/viewer/2022070418/56815915550346895dc63faf/html5/thumbnails/29.jpg)
What covers the earth?
• Agriculture: about 38% of Earth’s land surface– 26% pasture for domestic animals– 12% crops or arable land
![Page 30: Land](https://reader036.vdocument.in/reader036/viewer/2022070418/56815915550346895dc63faf/html5/thumbnails/30.jpg)
Is grazing sustainable?
• Overgrazing
• Leads to erosion
![Page 31: Land](https://reader036.vdocument.in/reader036/viewer/2022070418/56815915550346895dc63faf/html5/thumbnails/31.jpg)
Wetlands drained for agricultureFigure 12.15
![Page 32: Land](https://reader036.vdocument.in/reader036/viewer/2022070418/56815915550346895dc63faf/html5/thumbnails/32.jpg)
Wetland draining
• Bad government policy (early 20th c.)
• View at the time: draining wetlands to make farmland worthless swamp to valuable ecosystem
• Today: Conservation Reserve Program pays farmers to take erodable land out of production
![Page 33: Land](https://reader036.vdocument.in/reader036/viewer/2022070418/56815915550346895dc63faf/html5/thumbnails/33.jpg)
Farm subsidies
• EWG || Farm Subsidy Database
• This data base lists payments to farmers for a variety of reasons:– To conserve their land– To NOT grow a crop
![Page 34: Land](https://reader036.vdocument.in/reader036/viewer/2022070418/56815915550346895dc63faf/html5/thumbnails/34.jpg)
Federal lands
• National Parks
• National Forests
• Wilderness Areas
• National Wildlife Refuge
![Page 35: Land](https://reader036.vdocument.in/reader036/viewer/2022070418/56815915550346895dc63faf/html5/thumbnails/35.jpg)
Parks and reserves
• National Parks – public lands protected from resource extraction - 79 million acres
• National Wildlife Refuges – managed for various uses from preservation of biodiversity to hunting – 91 million acres
• Wilderness areas – off limits to development, open to recreation
![Page 36: Land](https://reader036.vdocument.in/reader036/viewer/2022070418/56815915550346895dc63faf/html5/thumbnails/36.jpg)
National Parks
• Strict preservation • Pristine areas • Protect both natural and historic features• Allow light recreation—e.g. hiking,
camping– No hunting, no pets on trails,
• Managed by National Park Service, Department of Interior
![Page 37: Land](https://reader036.vdocument.in/reader036/viewer/2022070418/56815915550346895dc63faf/html5/thumbnails/37.jpg)
National Forests
• Emphasize multiple use– Resource preservation, but also:– Lumber– Cattle grazing – Minerals– Motorized recreation– Hunting– Dogs allowed on trails
• Managed by US Forest Service, Department of Agriculture
![Page 38: Land](https://reader036.vdocument.in/reader036/viewer/2022070418/56815915550346895dc63faf/html5/thumbnails/38.jpg)
Wilderness areas
• Can be part of a National Park or Forest
• Must remain free of roads and structures
• Motorized transport not allowed, including all-terrain vehicles or motorboats.
• Hunting IS allowed, unless the wilderness area is in a National Park
![Page 39: Land](https://reader036.vdocument.in/reader036/viewer/2022070418/56815915550346895dc63faf/html5/thumbnails/39.jpg)
National Wildlife Refuges
• First in US: 1903.– TR designated Pelican Island in Florida
• Habitat for species– Including migratory
• Hunting and fishing usually allowed
• Managed by the Fish and Wildlife Service, department of the Interior
![Page 40: Land](https://reader036.vdocument.in/reader036/viewer/2022070418/56815915550346895dc63faf/html5/thumbnails/40.jpg)
Opponents of land restrictions
• Wise-use movement
![Page 41: Land](https://reader036.vdocument.in/reader036/viewer/2022070418/56815915550346895dc63faf/html5/thumbnails/41.jpg)
Design of parks for wildlife
• How best preservee endangered or threatened species?
• Key debate: SLOSS» Single Large Or Several Small
![Page 42: Land](https://reader036.vdocument.in/reader036/viewer/2022070418/56815915550346895dc63faf/html5/thumbnails/42.jpg)
Fragmentation of habitatFigure 12.20c
• Fragmented habitat is a HUGE factor in the decline of biodiversity
• Even when total amount of habitat doesn’t change much, many species require big areas.
![Page 43: Land](https://reader036.vdocument.in/reader036/viewer/2022070418/56815915550346895dc63faf/html5/thumbnails/43.jpg)
Corridors
• Roadless areas in Montana in green, National Parks in purple
• Yellowstone
lower right • Corridors help
connect small ``islands’’ of habitat, making one larger effective habitat.
![Page 44: Land](https://reader036.vdocument.in/reader036/viewer/2022070418/56815915550346895dc63faf/html5/thumbnails/44.jpg)
Why corridors?
• Allow animals, plants to disperse
• Enable gene flow– A population of 20 individuals may suffer
inbreeding depression. If five populations of 20 individuals are connected, dispersal may allow it to function like one population of 100.
• Protection against natural disasters that may wipe out one population
![Page 45: Land](https://reader036.vdocument.in/reader036/viewer/2022070418/56815915550346895dc63faf/html5/thumbnails/45.jpg)
Urbanization: what is it?
• Shift of human population to cities– 1930: ~30% world pop in cities– 2007: ~50%
• Conversion of green space (forests, farms, wetlands) to black space (highways, parking lots, asphalt
![Page 46: Land](https://reader036.vdocument.in/reader036/viewer/2022070418/56815915550346895dc63faf/html5/thumbnails/46.jpg)
Effects of urbanization(conversion of green space to asphalt, concrete)
• Heat island
• Increased amount of impervious surface, leading to – A) flow of pollutants to streams– B) rapid rise in stream levels
![Page 47: Land](https://reader036.vdocument.in/reader036/viewer/2022070418/56815915550346895dc63faf/html5/thumbnails/47.jpg)
• Heat island
• NYC temp. map
• Can you locate 3 places with the MOST vegetation on this map?
![Page 48: Land](https://reader036.vdocument.in/reader036/viewer/2022070418/56815915550346895dc63faf/html5/thumbnails/48.jpg)
VEGETATION
* Central Park *Central Staten
Island* Central to NE
Queens
![Page 49: Land](https://reader036.vdocument.in/reader036/viewer/2022070418/56815915550346895dc63faf/html5/thumbnails/49.jpg)
Sprawl
• The spread of low-density urban or suburban development outward from an urban center
![Page 50: Land](https://reader036.vdocument.in/reader036/viewer/2022070418/56815915550346895dc63faf/html5/thumbnails/50.jpg)
• Warren County, NJ: this shows pattern of sprawl development fragmenting farmland typical of rural NJ last 50 years
![Page 51: Land](https://reader036.vdocument.in/reader036/viewer/2022070418/56815915550346895dc63faf/html5/thumbnails/51.jpg)
Why does sprawl happen?
• Automobile and cheap fossil fuels
• Desire of urban dwellers for more space
• Changing nature of work; telecommuting
• Once suburbs established:– Good schools– Road networks
![Page 52: Land](https://reader036.vdocument.in/reader036/viewer/2022070418/56815915550346895dc63faf/html5/thumbnails/52.jpg)
DAILY QUESTION
• Describe some of the effects of sprawl.
![Page 53: Land](https://reader036.vdocument.in/reader036/viewer/2022070418/56815915550346895dc63faf/html5/thumbnails/53.jpg)
Figure 12.20c