1. Chapt 8 Environmental Science
“The size of the parcel of land matters less than the relationship of the people to it.”
Frances Moore Lappe and Joseph Collins
American Authors
Human Impact Notes
Chapt 8 Environmental Science

2. Chapt 8.2 How We Use Land
As populations grow, more land and resources are needed to support it; come from rural lands
Non-urban lands are being harvested: forests (for paper, furniture and home construction); grasslands (supporting livestock); mineral resources
These areas are becoming stressed by overuse

3. Harvesting Trees
Harvested trees are used for making paper, furniture, home building; we use an enormous amount of wood
Worldwide: 1800 cu. Cm of wood per person each day; In US, we use 3.5 times this amount (equal to one 30 m tree/year)
1.5 billion people in developing countries depend on firewood for fuel
Forest land is very valuable; In developing countries, many are being removed for farming or ranching; thought to improve quality of life

4. Deforestation
Forests are being cleared at an alarming rate and has become an environmental issue
Defined as the removal of tress without replacing them; most prevalent in tropical rain forests (developing countries)
Rain forests have poor soil; cannot support crops for only a short time; therefore, farmers need to continuously clear more forest areas
Two types of clearing the land: Clear-cutting (removing all the trees from the land – damages animal habitats, increases soil erosion) & Selective cutting (removing only the middle aged or mature trees, the rest are left alone and are replaced by the seedlings – less damaging to the environment.

5. Reforestation
The process of replacing trees that have died or been cut down; happens naturally from seeds that fall from nearby trees or humans replant seeds or seedlings
When large numbers of trees are removed this cannot occur naturally because of the soil erosion and lack of shade for the delicate seedlings
If successful, it can take 20 – 50 years or more to re-grow a forest
Some governments require reforestation; 90% of all timber comes from forests not managed by governments; many are private owners
Many states now require private landowners to reforest after timber is harvested

6. Protecting Forests
Many governments are currently working to improve reforestation efforts and promote less destructive harvesting methods
Private organizations have also established effective tree-planting programs; help to guarantee survival of forests
Important to have these programs to help protect our forests and their resources

7. Ranching
Rangelands support grasses and shrubs that are used by ranchers for grazing animals such as cattle, sheep and goats
Essential for maintaining the world’s food supply
Current population growth indicates a 40% increase in food production from rangeland between 1977 and 2030

8. Problems on the Range
Grasses on the rangelands are highly adaptable and live through droughts, freezes, fires and animal grazing; the growing point of the grasses is at the base of every leaf; if the upper portion of the leaf is damaged, it will grow back; the root system consists of fibrous, dense mats; they hold the soil together to prevent erosion
Overgrazing in an area will destroy the grasses beyond recovery; ranching in some parts of the world has contributed to the destruction of tropical forests

9. Maintaining the Range
Public Rangelands Improvement Act (1978) has helped to improve the management of public ranges; includes two main components – grazing management and range improvement
Grazing management – limiting animal herds to sizes the land can support; moving animals around to protect the plants
Range improvement – eliminating sagebrush and other weedy plants that invade overgrazed land; replanting vegetation; digging water holes to keep livestock from overgrazing

10. Mining
A surprising amount of land is used for mining minerals; used in cars, stereos, refrigerators, buildings, concrete, glass, brick and many other products we used everyday
Minerals – solid substances found in nature and consist of a single element or compound (salt, gold, silver, iron, copper, aluminum)
Two methods for extracting minerals: open-pit mining - machines dig large holes and remove ore; and strip-mining - huge bull-dozers and other machines are used to clear away large strips of the Earth’s surface

11. The Effects of Mining
Causes environmental damage; disruption of the land and ugly piles of waste materials left behind; habitats are lost; natural ecosystems are disrupted
Large scale removal of vegetation can cause land erosion and landslides; toxic materials left behind can pollute both air and water; lots of energy is used extract and process the material
US mines produce more waste than all the cities and towns combined; copper mines produce 1200 metric tons of waste per metric ton of copper metal produced

12. Responsible Mining
One way to reduce the damage from mining is to restore the land to the condition it was before the mining began (reclamation)
Environmental laws in the US now require companies to reclaim the mining sites on private land; some states have laws requiring reclamation on private land
Another way to reduce the destructive effects of mining is to reduce the need for more minerals – by recycling

13. 8.3 Public Land in the United States
In the early 1870’s, explorers expressed concern about the vast beauty of the west and asked the government to set aside that land for public use; birth of our national parks
The US government established 55 national parks and other protected lands to be used as public lands
US has encouraged other nations to do the same

14. This Land Belongs to You and Me
40% of all the land in the US is publicly owned
Managed by federal, state and local governments
Most of this government owned land is out west and Alaska; if you are a US citizen, you are a partial owner of these lands

15. Managing Our Public Land
Because land resources are so valuable, this land can be used in several ways (multiple-use management); proving the greatest value for the greatest number of people
Ex: National forest (recreation, logging, mining); private individuals and corporations can often harvest or extract natural resources
Problem: different people have different ideas of how this land should be used; you will see battles between developers and conservationists

16. Wilderness
Wilderness Act of 1964 defines wilderness as an area in which the land and the ecosystem it supports are protected from all development
657 regions covering 104 million acres have been designated as wilderness (open to hiking, fishing, boating – without a motor, camping); cannot build roads or use motorized equipment
Provides habitats for wild animals and plants

17. Troubled Lands
As populations grow, people are using those wilderness areas and destroying them by trampling plants, eroding soil from trails and campsites, bathing, washing dishes (polluting rivers and streams), and leaving behind trash
Originally, mining and ranching were allowed in wilderness areas (until 1983); filed petitions to remain in operation even to this day; nearby effects of grazing, logging, factories (air pollution) still affect these regions today

18. “People Control” in Wilderness Areas
Limits have been established in some areas (how many people who can hike and camp); must apply for permits
Some areas are off limits to camping and are patrolled
Volunteers help to pick up trash and build trails; education programs are being implemented to help people better understand and reduce the impact on the natural world