Chapter 18

Land Resources

Land Resources and Conservation

Importance of natural areas• Areas of low human density known as non-urban

or rural lands.

• Ecosystem services from these areas allow urban concentrations to exist. (environmental services such as clean air, clean water, fertile soil).

Land Use in these Natural Areas

• Provide habitat, flood & erosion control, & groundwater recharge.

• Natural areas also break down pollutants and recycle wastes.

• Provide recreation (camping, hiking, fishing)

Wilderness•Wilderness: Unspoiled regions where people visit but do not inhabit.

•Wilderness Act of 1964 established federally owned lands to retain “primeval” quality (no permanent improvements or houses).

•These lands remain unchanged for the benefit of future generations.

Wilderness•Wilderness areas range from very small (The Big Gum Swamp in Florida @ 13,660 acres) to huge (Selway-Bitterroot Wilderness Area in Idaho @ 1.3 million acres).

Wilderness•Wilderness areas are monitored by the NPS, USFS, FWS, and BLM.

•630 wilderness areas @ 102 million acres in the U.S., including mountains, tundra, deserts, & wetlands

•42% of wilderness areas are in national parks.

National Parks

• Yellowstone National park was the 1st (1872)

• The National Park System (NPS) parks was established in 1916 and operates historic sites, battlefields, buildings, and towns in addition to natural areas.

Problems with Wilderness Areas•Dilemma: preservation or human use and enjoyment?

•Millions of visitors erode hiking trails, soil, water, waste, air pollution , litter, trash, traffic congestion.

•# of visitors is now limited in some parks.

Problems with Wilderness Areas•Exotic species can invade wilderness and upset the ecological balance.

•Example: Pine blister Rust (fungus) is wiping out the White Pine (Pinus strobus) population.

Result...Pine seeds Grizzly...Decline

•Organization may have to plant disease resistant white pine trees. Is this still wilderness?

Problems with Wilderness Areas

Wild and Scenic Rivers

• Wild & Scenic Rivers Act was passed in 1968 to protect rivers of aesthetic, historic, & ecological value.

• Not wilderness but little or no development.

Wild and Scenic Rivers

NPS maintains the National River Inventory with 170 river segments @ 11,300 miles.

• Recreation = yes • Mining = yes • Development = no

Wildlife Refuges

National Wildlife Refuge system was established by Theodore “Teddy” Roosevelt in 1903.

535 refuges with at least one in each of the 50 states with 38.4 million hectares (95 million acres).

These represent all the major ecosystems in the U.S. and are home to most of the endangered species

(Whooping Cranes).

Fish & Wildlife Service operates these lands for observation, fishing, hunting, photography, and

education.

Whooping Cranes

Forests• Forests occupy less than 1/3 of the Earth’s total land

area.

• Forests have economic as well as ecological value.

• Forests provide timber for fuel, paper, and construction.

• Nuts, fungi, fruits, & medicines. Employment for millions, recreation and “escape” from urban areas.

Forests• Forests provide ecosystem services;• They control the local climate via transpiration

(natural cooling).• Control global biogeochemical cycles (nitrogen and

carbon cycles) • Forests are carbon sinks & absorb copious amounts

of CO2 from the atmosphere.• Roots anchor soil, protect watersheds, & provide

habitat for varieties of organisms.

•

Forest Management Practices

• Tree “farms” or plantations are often monocultures with one variety of tree. Low diversity provides little habitat/Disease prone.

• Herbicides & fungicides are used on tree farms because monocultures are more prone to disease & pests.

• These farms limit the use of existing forests for timber and timber products.

Forests

• Natural Regulation: involves letting nature take its course most of the time, with corrective actions being taken as needed.

“New” Forest Management Practices

• Ecologically Sustainable Forest Management involves mixing trees of different ages and species to increase diversity and available habitat for organisms as well as conserve forests for harvesting.

Management Practices• Loggers, environmentalists, farmers, indigenous

peoples, and government agencies need to cooperate for this type of management to be successful.

• Wildlife Corridors are uncut to set aside zones that are connected to nearby un-logged areas.

Wildlife Corridors

Deforestation• Increased loss of soil due to erosion and loss

of habitat.• The World Commission of Forests was

established at the 1992 Earth Summit.• 1999 report that the Earth’s forests are

decreasing by 15 million hectares (37 million acres) annually.

• Major causes of deforestation; fires, drought, clearcutting, agriculture, construction, tree harvesting, pests, and disease.

•

Deforestation

Deforestation

Deforestation leads to...

• Decreased soil fertility

• More runoff and sediment in waterways

• Loss of species

• Alteration of global climate???

• Increase in global temperature???

U.S. Forests• Vermont’s forests are increasing,.• The Rockies, New England, & the Great

Lakes regions have been constant.

• Conservation easements can protect forests by owners selling the right to develop the land to the U.S. government. The government then protects the land for a certain # of years.

Do Now- Harvesting Practices• Compare the 4 Types of tree harvesting in

terms of methods, cost, and economic gain.

• Selective Cutting

• Shelterwood Cutting

• Seed tree Cutting

• Clearcutting(even-ages cutting)

Harvesting PracticesSelective Cutting: fells single trees or small

groups of trees.

Shelterwood Cutting: fells all the mature trees in an area over time.

• Seed tree Cutting: fells almost all of the trees in an area except a few trees that are left to re-seed the area.

• Clearcutting (even-age harvesting): fells all the trees from an area. (Cheapest type $$)

Harvesting Practices

Clearcuttin’ Phil says “Clearcutting is the cheapest method!”

Tropical Forests

• Tropical RainForests: have 200 or more cm of rain annually (>79 in).

• These are found in Central & S. America, S.E. Asia, and Africa. Brazil, Congo, & Indonesia have the majority of this type of forest.

Tropical Forests• Tropical Dry Forests: have less than 200

cm of rain annually (<79 in). During the dry season these forests shed their leaves & become dormant similar to deciduous tree in temperate climates.

• These are disappearing rapidly in S. Asia, Indonesia, C. America, and the Phillipines.

Tropical Forests• These forests both (rain and dry) are

disappearing at a rate of 12.6 hectares (31.1 million acres) annually.

• All will be gone at current rate by the first half of the 22nd century (2150) but probably sooner .

Why are forests disappearing?

• Population growth seems to be the major cause.• Causes differ based upon economic, cultural, &

social issues.• Govt. policies sometimes favor deforestation ex:

Brazil selling forest to fast food companies (McDonald’s) for grazing land.

• 1999 Brazil set aside 10% of rainforest for conservation.

• Sponsored by the World Bank & the WWF (World Wildlife Fund).

Why are forests disappearing?• Subsistence agriculture causes

deforestation. Families produce enough to survive & that’s it. They don’t own the land they use. Farmers typically follow logging roads, and slash & burn the forest to raise crops there. 1st batch of crops use nutrients from the burn but then soil quality declines fast. So the family then moves to the next patch of forest to start the process again. Ranchers use the land soon after.

Why are forests disappearing?• Compared to 50 years ago, only ½ of the

world’s tropical forests remain.

• Commercial logging contributes to 20% of tropical forest depletion.

• Cattle Ranching: contributes to 12% of tropical forest depletion.

• 20 years after ranching the land is left as scrub savanna.

Why are forests disappearing?• Plantation style agriculture grows citrus

fruits (pineapple) and bananas for export.

• DDT and fertilizers are then introduced to the area.

• Dry Tropical forests also provide biomass energy for families. (heat, light, cooking)

Boreal Forests

• Occur in Taiga and comprise the world’s largest Biome (11% of Earth’s land area).

• Most wood & wood fiber comes from this area via clearcutting. (almost twice the area as Amazonia).

Tongass National Forest• Temperate rainforest similar to the Olympia

National Forest in Washington State.• Contains old growth forest (primary

succession) with 700 year old trees. • Grizzly Ursus arctos horribilis) & • Bald Eagles (Haliaetus leuoccephalus)

• Clearcutting in the Tongass was slowed due to the Tongass Management Plan (Modified 1997 Forest Plan).

Rangelands• These important grasslands are comprised of

grasses, forbs (small herbaceous plants), and shrubs with extensive fibrous root systems.

• Cattle, sheep, goats, and other domestic animals graze these lands.

• Rangelands are renewable within a specific carrying capacity.

Rangeland Management issues

• Overgrazing can result in barren, exposed soil that is prone to erosion. (remember the dust bowl)

• Degradation of soil affects future productivity.

• Continual degradation leads to desertification, the development of unproductive desert like conditions in once fertile areas.

Rangelands• Roughly 2/3 of U.S. rangelands are

privately owned, the feds own much of the rest.

• There are more than 89 million hectares of federally owned rangeland in the U.S.

• The BLM manages most of the rangelands with the remainder overseen by the USFS.

Rangelands• The federal government issues permits that

allow private livestock operators to use public rangelands for grazing.

• Others feel that public rangelands should be used for habitat, recreation, and aestethic value.

Rangeland Management issues

• 44,000 Wild horses and burros are not indigenous and need to be managed.

• Adopt-a-horse program sold to slaughterhouses.

• Contraceptives are now used for females.

Do Now-Wetlands

• Definition?

• Ownership?

• Ecosystem services and economic value?

• Threats?

• Protection?

Wetlands• Transitional areas-Wet part or all of year

• Partially protected by Clean Water Act of 1972.

• Gov’t owns 25%/ Rest is privately held

• Filter groundwater, breeding grounds, flood control, home to many species, commercial use.

• Are being drained for development, mosquito control, mining, solid waste disposal.

Coastlines

• Are being overdeveloped, highly polluted, and overfished.

• Estuaries are “nurseries for the sea”

Seawalls and Beach erosion

Suburban Sprawl

Suburban sprawl results in...

• Loss of agricultural land

• Urbanization...More pollution

• Depletion of resources...Ex. “water”