1. Chapter 6 Lecture Outline
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2. Learning Outcomes After studying this chapter, you should be able to answer the following questions:
• What portion of the world’s original forests remain? • What activities threaten global forests? What steps can be taken to preserve them? • Why is road construction a challenge to forest conservation? • Where are the world’s most extensive grasslands? • How are the world’s grasslands distributed, and what activities degrade grasslands? • What are the original purposes of parks and nature preserves in North America? • What is a wilderness? Why are wilderness areas both important and controversial? • What are some steps to help restore natural areas?

3. What a country chooses to save is what a country chooses to say about itself. –Mollie Beatty, former director, U.S. Fish and Wildlife Service

4. 6.1 World Forests
Forests and grasslands together occupy almost 60 percent of global land cover (fig. 6.2). These ecosystems provide many of our essential resources, such as lumber, paper pulp, and grazing lands for livestock. They also provide essential ecological services, including regulating climate, controlling water runoff, providing wildlife habitat, purifying air and water, and supporting rainfall. Forests and grasslands also have scenic, cultural, and historic values that deserve protection. Forests and grasslands are also among the most heavily disturbed ecosystems (chapter 5).
Forests and grasslands together occupy almost 60 percent of global land cover.
These ecosystems provide many of our essential resources.
They also provide essential ecological services.

5. Boreal and tropical forests are most abundant
Old-growth forests are those that cover a large enough area and have been undisturbed by human activities long enough that trees can live out a natural life cycle.
Some of the world’s most biologically diverse regions are undergoing rapid deforestation, including Southeast Asia and Central America.
Forests are a huge carbon sink, storing some 422 billion metric tons of carbon in standing biomass.
Clearing and burning of forests releases much of this carbon into the atmosphere (chapter 9) and may contribute substantially to global climate change. Moisture released from forests also contributes to rainfall. For example, recent climate studies suggest that deforestation of the Amazon could reduce precipitation in the American Midwest.
Among the forests of greatest ecological importance are the remnants of primeval forests that are home to much of the world’s biodiversity, endangered species, and indigenous human cultures.
Sometimes called frontier forests, old-growth forests are those that cover a large enough area and have been undisturbed by human activities long enough that trees can live out a natural life cycle and ecological processes can occur in relatively normal fashion. That doesn’t mean that all trees need be enormous or thousands of years old. In some old-growth forests, most trees live less than a century before being killed by disease or some natural disturbance, such as a fire. Nor does it mean that humans have never been present.

6. Forests provide many valuable products
Wood plays a part in more activities of the modern economy than does any other commodity.
Wood plays a part in more activities of the modern economy than does any other commodity. There is hardly any industry that does not use wood or wood products somewhere in its manufacturing and marketing processes. Think about the amount of junk mail, newspapers, photocopies, and other paper products that each of us in developed countries handles, stores, and disposes of in a single day. Total annual world wood consumption is about 4 billion
m3. This is more than steel and plastic consumption combined.
International trade in wood and wood products amounts to more than $100 billion each year. Developed countries produce less than half of all industrial wood but account for about 80 percent of its consumption. Less-developed countries, mainly in the tropics, produce more than half of all industrial wood but use only 20 percent.
Paper pulp, the fastest growing type of forest product, accounts for nearly a fifth of all wood consumption. Most of the world’s paper is used in the wealthier countries of North America, Europe, and Asia. Global demand for paper is increasing rapidly.

7. Tropical forests are being cleared rapidly Causes of deforestation
Tropical forests are among the richest and most diverse terrestrial systems. Although they now occupy less than 10 percent of the earth’s land surface, these forests are thought to contain more than two-thirds of all higher plant biomass and at least half of all the plant, animal, and microbial species in the world. A century ago, an estimated 12.5 million km2 of tropical lands were covered with closed-canopy forest. This was an area larger than the entire United States. The FAO estimates that about 9.2 million ha, or about 0.6 percent, of the remaining tropical forest
is cleared each year (fig. 6.6).

8. Forest protection
About 12 percent of all world forests are in some form of protected status, but the effectiveness of that protection varies greatly.
Costa Rica has one of the best plans for forest guardianship in the world.
Attempts are being made there not only to rehabilitate the land (make an area useful to humans) but also to restore the ecosystems to naturally occurring associations.

9. Debt-for-nature swaps
Banks, governments, and lending institutions now hold nearly $1 trillion in loans to developing countries.
There is little prospect of ever collecting much of this debt, and banks are often willing to sell bonds at a steep discount—perhaps as little as 10 cents on the dollar.
Conservation organizations buy debt obligations on the secondary market at a discount and then offer to cancel the debt if the debtor country agrees to protect or restore an area of biological importance.
There have been many such swaps. Conservation International, for instance, bought $650,000 of Bolivia’s debt for $100,000—an 85 percent discount. In exchange for canceling this debt, Bolivia agreed to protect nearly 1 million ha (2.47 million acres) around the Beni Biosphere Reserve in the Andean foothills. Ecuador and Costa Rica have had a different kind of debt-for-nature swap. They have exchanged debt for local currency bonds that fund activities
of local private conservation organizations in the country. This has the dual advantage of building and supporting indigenous environmental groups while protecting the land.
Critics, however, charge that these swaps compromise national sovereignty and do little to reduce the developing world’s debt or to change the situations that led to environmental destruction in the first place.

10. Temperate forests also are at risk
Many endemic species, such as the northern spotted, are so highly adapted to the unique conditions of these ancient forests that they live nowhere else.
Less than 10 percent of old-growth forest in the United States remains intact.
Old-growth forests The most contentious forestry issues in the United States and Canada in recent years have centered on logging in old-growth forests in the Pacific Northwest. As you’ve learned in the opening case study
for this chapter, these forests have incredibly high levels of biodiversity, and they accumulate more total biomass in standing vegetation per unit area than any other ecosystem on earth (fig. 6.9).
Many endemic species, such as the northern spotted owl (fig. 6.10), Vaux’s swift, and the marbled murrelet, are so highly adapted to the unique conditions of these ancient forests that they live nowhere else.
Less than 10 percent of old-growth forest in the United States remains intact, and 80 percent of what remains is scheduled to be cut in the near future.

11. Harvest methods
Some alternatives to clear-cutting include shelterwood harvesting, in which mature trees are removed in a series of two or more cuts, and strip-cutting, in which all the trees in a narrow corridor are harvested. For many forest types, the least disruptive harvest method is selective cutting, in which only a small percentage of the mature trees are taken in each 10- or 20-year rotation. Ponderosa pine, for example, are usually selectively cut to thin
stands and improve growth of the remaining trees. A forest managed by selective cutting can retain many of the characteristics of age distribution and groundcover of a mature old-growth forest.
Most lumber and pulpwood in the United States and Canada currently are harvested by clear-cutting, in which every tree in a given area is cut, regardless of size.

12. Should we subsidize logging on public lands?
People in the U.S. are calling for an end to all logging on federal lands because ecological services, from maintaining river levels for fish and irrigation to recreation, generate more revenue at lower costs.
Many communities depend on logging jobs, but these jobs depend on subsidies.
The federal government builds roads, manages forests, fights fires, and sells timber for less than the administrative costs of the sales.
Some argue that logging should be restricted to privately owned lands. Just 4 percent of the nation’s timber comes from national forests, and this harvest adds about $4 billion to the American economy per year. In contrast, recreation, fish and wildlife, clean water, and other ecological services provided by the forest, by their calculations, are worth at least $224 billion each year. Timber industry officials, on the other hand, dispute these claims,
arguing that logging not only provides jobs and supports rural communities but also keeps forests healthy. What do you think? Could we make up for decreased timber production from public lands by more intensive management of private holdings and by substitution or recycling of wood products? Are there alternative ways you could suggest to support communities now dependent on timber harvesting?

13. Fire management
Following a series of disastrous fire years in the 1930s, in which hundreds of millions of hectares of forest were destroyed, whole towns burned to the ground, and hundreds of people died, the U.S. Forest Service adopted a policy of aggressive fire control in which every blaze on public land was to be out before 10 a.m. Smokey Bear was adopted as the forest mascot and warned us that “only you can prevent forest fires.” Recent studies, however, of fire’s ecological role suggest that our attempts to suppress all fires may have been misguided. Many biological communities are fire-adapted and require periodic burning for regeneration. Furthermore, eliminating
fire from these forests has allowed woody debris to accumulate, greatly increasing the chances of a very big fire.

14. Ecosystem management
In the 1990s the U.S. Forest Service began to shift its policies from a timber production focus to ecosystem management, which attempts to integrate sustainable ecological, economic, and social goals in a unified, systems approach. Some of the principles of this new philosophy include:
• Managing across whole landscapes, watersheds, or regions over ecological time scales.
• Considering human needs and promoting sustainable economic development and communities.
• Maintaining biological diversity and essential ecosystem processes.
• Utilizing cooperative institutional arrangements.
• Generating meaningful stakeholder and public involvement and facilitating collective decision making.
• Adapting management over time, based on conscious experimentation and routine monitoring.
Some critics argue that we don’t understand ecosystems well enough to make practical decisions in forest management on this basis. They argue we should simply set aside large blocks of untrammeled nature to allow for chaotic, catastrophic, and unpredictable events. Others see this new approach as a threat to industry and customary ways of doing things.
Ecosystem management is an U.S. Forest Service policy that attempts to integrate sustainable ecological, economic, and social goals in a unified, systems approach.

15. 6.2 Grasslands
Grasslands, chaparral, and open woodlands are attractive for human occupation, so they frequently are converted to cropland, urban areas, or other human-dominated landscapes.
Worldwide the rate of grassland disturbance each year is three times that of tropical forest.
Desertification is the process of conversion of once fertile land to desert.
When grazing lands are abused by overgrazing—especially in arid areas—rain runs off quickly before it can soak into the soil to nourish plants or replenish groundwater. Springs and wells dry up. Seeds can’t germinate in the dry, overheated soil. The barren ground reflects more of the sun’s heat, changing wind patterns, driving away moisture-laden clouds, and leading to further desiccation. This process of conversion of once fertile land to desert is
called desertification.

16. Overgrazing threatens many rangelands
As is the case in many countries, the health of most public grazing lands in the United States is not good. Political and economic pressures encourage managers to increase grazing allotments beyond the carrying capacity of the range. Lack of enforcement of existing regulations and limited funds for range improvement have resulted in overgrazing, damage to vegetation and soil including loss of native forage species and erosion. The Natural
Resources Defense Council claims that only 30 percent of public range-lands are in fair condition, and 55 percent are poor or very poor (fig. 6.15).
On the other hand, ranchers defend their way of life as an important part of western culture and history. Although few cattle go directly to market from their ranches, they produce almost all the beef calves subsequently shipped to feedlots. And without a viable ranch economy, they claim, even more of the western landscape would be subdivided into small ranchettes to the detriment of both wildlife and environmental quality. What do you think? How much should we subsidize extractive industries to preserve rural communities and traditional occupations?
Ranchers are experimenting with new methods: Where a small number of livestock are free to roam a large area, they generally eat the tender, best-tasting grasses and forbs first, leaving the tough, unpalatable species to flourish and gradually dominate the vegetation. In some places, farmers and ranchers find that short-term, intensive grazing helps maintain forage quality.

17. Some biomes are relatively unprotected.
Figure 6.20 shows a comparison between the percent of each major biome in protected status. Not surprisingly, there’s an inverse relationship between the percentage converted to human use (and where people live) and the percentage protected. Temperate grasslands and savannas (such as the American Midwest) and Mediterranean woodlands and scrub (such as the French Riviera or the coast of southern California) are highly domesticated, and,
therefore, expensive to set aside in large areas. Temperate conifer forests (think of Siberia, or Canada’s vast expanse of boreal forest) are relatively uninhabited, and therefore easy to put into some protected category.

18. 6.3 Parks and Preserves
The idea of providing natural space for recreation, and to preserve natural environments, has really developed in the past 50 years (fig. 6.18). While the first parks were intended mainly for the recreation of growing
urban populations, parks have taken on many additional purposes. Today we see our national parks as playgrounds for rest and recreation, as havens for wildlife, as places to experiment with ecological management, and as opportunities to restore ecosystems.
Not all preserves are preserved: Even parks and preserves designated with a high level of protection
aren’t always safe from exploitation or changes in political priorities. Serious problems threaten natural resources and environmental quality in many countries. In Greece, the Pindus National Park is threatened by plans to build a hydroelectric dam in the center of the park. Furthermore, excessive stock grazing and forestry exploitation in the peripheral zone are causing erosion and loss of wildlife habitat.

19. Marine ecosystems need greater protection
As ocean fish stocks become increasingly depleted globally, biologists are calling for protected areas where marine organisms are sheltered from destructive harvest methods. As the opening case study for chapter 1 describes, limiting the amount and kind of fishing in marine reserves can quickly replenish fish stocks in surrounding
areas. In a study of 100 marine refuges around the world, researchers found that, on average, the number of organisms inside no-take preserves was twice as high as surrounding areas where fishing was allowed. In addition, the biomass of organisms was three times as great and individuals animals were, on average, 30 percent larger inside the refuge compared to outside. Recent research has shown that closing reserves to fishing even for a few months can have beneficial results in restoring marine populations.
Coral reefs are among the most threatened marine ecosystems in the world. Remote sensing surveys show that worldwide living coral covers only about 285,000 km 2 (110,000 mi 2 ), or an area about the size of Nevada. This is less than half of previous estimates, and 90 percent of all reefs face threats from rising sea temperatures, destructive fishing methods, coral mining, sediment runoff, and other human disturbance.

20. Conservation and economic development can work together
Ecotourism is tourism that is ecologically and socially sustainable.
Many of the most biologically rich communities in the world are in developing countries, especially in the tropics.
People in some developing countries are beginning to realize that their biological resources may be their most valuable assets, and that their preservation is vital for sustainable development.
Ecotourism (tourism that is ecologically and socially sustainable) can be more beneficial in many places over the long term than extractive industries, such as logging and mining. The What Can You Do? box (p. 145) suggests
some ways to ensure that your vacations are ecologically responsible.

21. Species survival can depend on preserve size and shape
For years, conservation biologists have disputed whether it is better to have a single large or several small reserves (the SLOSS debate). Ideally, a reserve should be large enough to support viable populations of endangered species, keep ecosystems intact, and isolate critical core areas from damaging external forces. For some species with small territories, several small, isolated refuges can support viables populations, and having several small reserves provides insurance against a disease, habitat destruction, or other calamities that might wipe out a single population. But small preserves can’t support species such as elephants or tigers, which need large amounts of space.
One proposed solution has been to create corridors of natural habitat that can connect to smaller habitat areas (fig. 6.27). Corridors could effectively create a large preserve from several small ones. Corridors could also allow populations to maintain genetic diversity or expand into new breeding territory. The effectiveness of corridors probably depends on how long and wide they are, and on how readily a species will use them.

22. Landscape Ecology
A science that examines the relationship between spatial patterns and ecological processes
One of the reasons large preserves are considered better than small preserves is that they have more core habitat, areas deep in the interior of a habitat area, and that core habitat has better conditions for specialized species than do edges. Edge effects is a term generally used to describe habitat edges: for example, a forest edge is usually more open, bright, and windy than a forest interior, and temperatures and humidity are more varied. For a
grassland, on the other hand, edges may be wooded, with more shade, and perhaps more predators, than in the core of the grassland area. As human disturbance fragments an ecosystem, habitat is broken into increasingly isolated islands, with less core and more edge. Small, isolated fragments of habitat often support fewer species, especially fewer rare species, than do extensive, uninterrupted ecosystems. The size and isolation of a wildlife
preserve, then, may be critical to the survival of rare species.
Landscape ecology is a science that examines the relationship between these spatial patterns and ecological processes, such as species movement or survival.

23. Practice Quiz
1. What do we mean by closed-canopy forest and old-growth forest? 2. What land use is responsible for most forest losses in Africa? In Latin America? In Asia? (fig. 6.7). 3. What is a debt-for-nature swap? 4. Why is fire suppression a controversial strategy? Why are forest thinning and salvage logging controversial? 5. What portion of the United States’ public rangelands are in poor or very poor condition due to overgrazing? Why do some groups say grazing fees amount to a “hidden subsidy”?

24. Practice Quiz continued…
6. What is rotational grazing, and how does it mimic natural processes? 7. How do the size and design of nature preserves influence their effectiveness? What do landscape ecologists mean by interior habitat and edge effects? 8. What percentage of the earth’s land area has some sort of protected status? How has the amount of protected areas changed globally (fig. 6.18)? 9. What is ecotourism, and why is it important? 10. What is a biosphere reserve, and how does it differ from a wilderness area or wildlife preserve?