Presentation is loading. Please wait.

Presentation is loading. Please wait.

Chapter 14: Land Use, Forests and Rangelands

Similar presentations


Presentation on theme: "Chapter 14: Land Use, Forests and Rangelands"— Presentation transcript:

1 Chapter 14: Land Use, Forests and Rangelands
In this chapter the following topics will be covered: Major world land uses World forest types and products derived from them Tropical forests: how they are being disrupted and to better use them Temperate forests Rangelands: their location and state of grazing Land ownership and land reform

2 World Land Uses About 4% of the world's total land surface is formally protected in parks, refuges, and preserves. Approximately 11% of the earth's landmass is used for crops. Rapidly increasing human populations and expanding forestry and agriculture have brought about extensive land-use changes throughout the world. Humans have affected every part of the globe and dominate most areas with temperate climate and good soils.

3

4 World Forests Forests play key roles in many natural processes and have scenic, cultural, and historic value. Forest Distribution About four fifths of the world's forest is classified as closed-canopy (that is tree crowns spread over 20% or more of the ground). The rest is open canopy or woodland in which tree crowns cover less than 20% of the ground. Old growth forests are those that cover a large enough area and have been undisturbed by humans long enough so that trees can carry out natural life cycles in a relatively normal ecological fashion. Only about 39% of forests worldwide are old growth.

5

6

7 Forest Products Wood plays a part in more activities of the modern economy than does any other commodity. Total world wood consumption is about 3.7 billion metric tons annually. Industrial Timber and roundwood (unprocessed logs) account for slightly less than one half of worldwide wood consumption. The United States, the former Soviet Union, and Canada are the largest producers of both industrial wood and paper pulp. Japan is the world's largest net importer of wood. More than half the people in the world depend on firewood or charcoal as their principal source of heating and cooking fuel. Consequently, fuel wood accounts for slightly more than half of all wood harvested worldwide. Burgeoning populations and dwindling forests have caused fuel wood shortages in many developing countries.

8 Forest Management Forest management involves planning for sustainable harvests, with particular attention paid to forest regeneration. Approximately 25% of the world's forests are managed scientifically for wood production. Most countries replant far less forest than is harvested or converted to other use. Monoculture forestry involves large plantations of single-species, single-use, intensive cropping. While monoculture forestry saves money and labor and produces high profits, it encourages pest and disease problems and soil erosion. Groups such as The New Forest Fund and Oxfam encourage planting of mixed species of fast-growing, multipurpose trees.

9 Tropical Forests Tropical forests are the richest, most diverse ecosystems on earth although they occupy less than 10% of its land surface. Diminishing Forests It is estimated that about 0.8% of the remaining tropical forest in the world is cleared away each year. There are a great number of conflicting opinions on exactly how fast the world is being deforested and what that deforestation means. Brazil is reported to have the highest rate deforestation in the world, but it also has by far the largest tropical forests. Cattle ranching, fruit plantations, mining, and illegal logging all contribute to the problem of deforestation.

10

11

12 Swidden Agriculture Swidden agriculture (sometimes called slash and burn agriculture) is an ancient farming technique that can be an ecologically sound way of obtaining a sustained yield from fragile soils if done carefully and in moderation. When done properly, swidden agriculture prevents erosion, eruptive insect infestations, and produces a sustainable yield of crops. After a year or two, the forest begins to take back over the plot and a new section of forest is cleared.

13 Logging and Land Invasions
Logging operations are another major source of forest destruction. Loggers are often only interested in harvesting the most valuable hardwoods and so may only take one or two trees per hectare. This often results in widespread destruction. Because of the interlocking nature of the canopy, bringing down one tree will often bring down dozens of others. Logging roads then open up the interior of the forest to settlement by people who attempt to turn forest into ranches and farms with disastrous ecological results.

14 Forest Protection Many nations, including Zaire, Brazil, and Costa Rica, have set aside large tracts of forest as national preserves. Grassroots reforestation projects are also working to protect and restore forests. Debt-for-Nature Swaps Debt for nature swaps refers to programs where conservancy organizations buy developing countries' debt obligations from banks and agree to cancel the debt if that country will agree to protect or restore an area of biological importance.

15 Temperate Forests Tropical forests are not the only endangered forest in the world. Temperate forests, especially those in the former Soviet Union, are also in danger of being destroyed. Ancient Forests of the Pacific Northwest Temperate rainforests are second only to tropical rainforests in their amount of biodiversity. Many species of animals (spotted owl, Vaux's swift, marbled murrelet) are so highly specialized that they live nowhere other than old growth, temperate forests. About 10% of the original old-growth forest still remains in the United States and approximately 80% of that is scheduled to be cut down in the near future.

16 Wilderness and Wildlife Protection
Many environmentalists would like to save all virgin forest remaining in the United States. Economic pressures are considerable, however. The forest products industry employs about 150,000 people in the Pacific Northwest and adds $7 billion annually to the economy. In 1989, environmentalists sued the U.S. Forest Service over plans to clear-cut most of the remaining old growth forest, arguing that spotted owls are endangered and must be protected. Federal courts agreed and set aside 1 million acres of ancient forest. This spurred a great deal of protesting and outrage from the logging community. Currently, a compromised forest management plan will allow some continued cutting but will also protect a high percentage of ancient old-growth forest.

17 Harvest Methods Clear cutting is a harvesting method in which every tree in a given area is cut regardless of its size. Coppicing is used to encourage stump sprouts from species such as aspen, oak, beech, or pine. In seed tree harvesting, some mature trees are left in an area to serve as a seed source for the clear cut patch. Strip cutting entails harvesting all the trees in a narrow corridor. Selective cutting involves taking only a few mature trees in an area. This is the least ecologically disruptive method of harvest. Logging roads also damage natural areas by tearing up soils and leaving long lasting scars.

18 Below-Cost and Salvage Sales
In 1995, Congress passed a budget bill allowing timber salvage sales that bypass ordinary environmental constraints or management quotas in areas where fire or disease have killed large numbers of trees. Fire Management For more than 70 years, firefighting has been a high priority for forest managers. Our vision of what forest fires do is misleading. Fire is a necessary and integral part of some forest ecosystems. Attempts to put out fires sometimes do more ecological damage than the fires themselves. The U.S. Park Service has begun a system of allowing some natural fires to burn.

19 Rangelands Pasture and open range occupy about 26% of the world's land
surface. More than half of all land is used at least occasionally as grazing land. More threatened American plant species occur in rangelands than any other major biome.

20

21 Range Management Careful monitoring of the numbers of animals and the conditions of the range, ranchers can keep livestock healthy and avoid overusing a section of land. Overgrazing and Land Degradation About one third of the world's range is threatened by overgrazing. Desertification is the process of denuding and degrading once fertile land into a desert cycle.

22

23

24

25 Forage Conversion by Domestic Animals
85% of the forage for ruminants worldwide comes from native rangelands and pasture. Harvesting Wild Animals Few people worldwide still depend on wildlife as a primary source of meat. Some research is beginning to show that, in Africa, harvesting wild game holds much more promise than cattle farming. Rangelands in the United States The health of most public grazing lands in the United States is not good. Political and economic pressures have led to a lack of enforcement of regulations and overgrazing. Fees charged for grazing on public lands are far below market value and represent an enormous hidden subsidy to western ranchers.

26 Land ownership and Land Reform
Many problems discussed in this chapter have their roots in land ownership and public policies concerning land use. Who Owns How Much? In most countries, it is a very small percent of the population that owns a very large percentage of the land.

27 Land Reform Land reform movements seek a redistribution of the land. Land reform is often a key component of agricultural modernization. Indigenous Lands Indigenous peoples make up about 10% of the world's population and occupy about 25% of its land. Many of these people possess deep ecological understandings of their environment and work to safeguard and protect it. Most countries have a sad history of denying land rights to the indigenous peoples.

28

29 Summary Most of the earth's land is inappropriate for agriculture and is ruined by attempts to cultivate it. While northern forests are growing faster than they are being harvested, tropical forests are in a great deal of danger. About one-third of the earth's rangelands are threatened by overgrazing. Land reform is an essential part of sound land-use management.


Download ppt "Chapter 14: Land Use, Forests and Rangelands"

Similar presentations


Ads by Google