Forestry

MANAGING AND SUSTAINING FORESTS  Forests provide a number of ecological and economic services that researchers have attempted to estimate their total monetary value. Figure 10-4

Global Outlook: Extent of Deforestation  Human activities have reduced the earth’s forest cover by as much as half.  Losses are concentrated in developing countries. Figure 10-7

Case Study: Deforestation and the Fuelwood Crisis  Almost half the people in the developing world face a shortage of fuelwood and charcoal. In Haiti, 98% of country is deforested. MIT scientist has found a way to make charcoal from spent sugarcane.

Harvesting Trees  Building roads into previously inaccessible forests paves the way for fragmentation, destruction, and degradation. Figure 10-8

Harvesting Trees  Trees can be harvested individually from diverse forests (selective cutting), an entire forest can be cut down (clear cutting), or portions of the forest is harvested (e.g. strip cutting). Figure 10-9

Harvesting Trees Effects of clear-cutting in the state of Washington, U.S. Figures and 10-11

Solutions  We can use forests more sustainably by emphasizing: Economic value of ecological services. Harvesting trees no faster than they are replenished. Protecting old-growth and vulnerable areas. Figure 10-12

CASE STUDY: FOREST RESOURCES AND MANAGEMENT IN THE U.S.  U.S. forests cover more area than in  Since the 1960’s, an increasing area of old growth and diverse second-growth forests have been clear-cut. Often replace with tree farms. Decreases biodiversity. Disrupts ecosystem processes.

Types and Effects of Forest Fires  Depending on their intensity, fires can benefit or harm forests. Burn away flammable ground material. Release valuable mineral nutrients. Figure 10-13

Types of Fires Surface fires – burn only undergrowth and leaf litter – Reduces chances of more destructive fires – Help recycle minerals – Release seeds for germination

Types of Fires Crown fires – start on the ground but eventually burn whole trees – Rapidly burning fires – Occur when there is a large build up of litter – Destroy vegetation – Kill wildlife – Increase soil erosion – Stop when they run out of fuel

Types of fires Ground fires – surface fires that go underground and burn decaying leaves and peat – May smolder for days or weeks – Difficult to detect and extinguish – consumes all or most of the organic cover, and exposes mineral soil or underlying rock – Usually occur during drought

Prescribed Burns intentional ignition of grass, shrub, or forest fuels for specific purposes according to predetermined conditions. – Expose mineral soil for seedbeds for regeneration of wind-disseminated species – Control of insects, diseases, and competing vegetation – Fuel reduction

Solutions: Controversy Over Fire Management  In 2003, U.S. Congress passed the Healthy Forest Restoration Act: The primary goal of this Act is to reduce fire danger. Allows timber companies to cut medium and large trees in 71% of the national forests. In return, must clear away smaller, more fire-prone trees and underbrush. Some forest scientists believe this could increase severe fires by removing fire resistant trees and leaving highly flammable slash.

Solutions: Reducing Demand for Harvest Trees  Tree harvesting can be reduced by wasting less wood and making paper and charcoal fuel from fibers that do not come from trees. Ex )Kenaf - paper production.

CASE STUDY: TROPICAL DEFORESTATION  Large areas of ecologically and economically important tropical forests are being cleared and degraded at a fast rate. Figure 10-16

CASE STUDY: TROPICAL DEFORESTATION  At least half of the world’s terrestrial plant and animal species live in tropical rain forests.  Large areas of tropical forest are burned to make way for cattle ranches and crops. Figure 10-17

Why Should We Care about the Loss of Tropical Forests?  About 2,100 of the 3,000 plants identified by the National Cancer Institute as sources of cancer- fighting chemicals come from tropical forests. Figure 10-18

Kenya’s Green Belt Movement: Individuals Matter  Wangari Maathai founded the Green Belt Movement.  The main goal is to organize poor women to plant (for fuelwood) and protect millions of trees.  In 2004, awarded Nobel peace prize. Figure 10-10A

NATIONAL PARKS  Countries have established more than 1,100 national parks, but most are threatened by human activities. Local people invade park for wood, cropland, and other natural resources. Loggers, miners, and wildlife poachers also deplete natural resources. Many are too small to sustain large-animal species. Many suffer from invasive species.

Case Study: Stresses on U.S. National Parks  Overused due to popularity.  Inholdings (private ownership) within parks threaten natural resources.  Air pollution. Figure 10-23

Wilderness Act of 1964 Provides for permanent protection of undeveloped and unexploited areas so that natural ecological processes can operate freely. 5% of land area in U.S. Preservation, not conservation. Limits recreational and commercial use

Forests and Rangeland Renewable Resources Research Act, 1978 Also known as the National Forest Management Act Authorizes the Secretary of Agriculture to conduct renewable resources research activities on national forest and rangelands, including research relating to fish and wildlife and their habitats. Encourages multiple-use and sustained yield management of our national forests and rangeland.

Lands managed by the U.S. federal government. U.S. citizens jointly own these and other public lands. Figure 25-9

NATURE RESERVES  Ecologists call for protecting more land to help sustain biodiversity, but powerful economic and political interests oppose doing this. Currently 12% of earth’s land area is protected. Only 5% is strictly protected from harmful human activities. Conservation biologists call for full protection of at least 20% of earth’s land area representing multiple examples of all biomes.

NATURE RESERVES  Large and medium-sized reserves with buffer zones help protect biodiversity and can be connected by corridors.  Costa Rica has consolidated its parks and reserves into 8 megareserves designed to sustain 80% if its biodiversity. Figure 10-10B

NATURE RESERVES  We can prevent or slow down losses of biodiversity by concentrating efforts on protecting global hot spots where significant biodiversity is under immediate threat.  Conservation biologists are helping people in communities find ways to sustain local biodiversity while providing local economic income.

 34 hotspots identified by ecologists as important and endangered centers of biodiversity. Figure 10-26

NATURE RESERVES  Wilderness is land legally set aside in a large enough area to prevent or minimize harm from human activities.  Only a small percentage of the land area of the United States has been protected as wilderness.

ECOLOGICAL RESTORATION  Restoration: trying to return to a condition as similar as possible to original state.  Rehabilitation: attempting to turn a degraded ecosystem back to being functional.  Replacement: replacing a degraded ecosystem with another type of ecosystem.  Creating artificial ecosystems: such as artificial wetlands for flood reduction and sewage treatment.

ECOLOGICAL RESTORATION  Five basic science-based principles for ecological restoration: Identify cause. Stop abuse by eliminating or sharply reducing factors. Reintroduce species if necessary. Protect area form further degradation. Use adaptive management to monitor efforts, assess successes, and modify strategies.