• The stock is the present accumulated quantity of natural capital. It is a supply accumulated for future use; a store.

• The natural income is any sustainable yield or rate of harvest from the stocks.

• Natural capital is the term used for ‘natural resources’ which can be exploited to produce natural income of goods and services.

• e.g. trees as timber that can be harvested and sold for money.

NATURAL CAPITAL and INCOME

3 categories of Natural Capital

Renewable - living species and ecosystems which can be replaced by natural productivity (photosynthesis!) as fast as they are used (e.g. food crops, timber).

Replenishable - non-living resources which are can be continuously restored by natural processes as fast as they are used (e.g stratospheric ozone layer, groundwater).

Non-renewable - Resources which cannot be replenished at the same rate at which they were used.

Any use of these resources implies depletion of the stock.

e.g. fossil fuels, minerals. If these resources are being

depleted we must: 1) improve efficiency of use

2) develop substitutes 3) recycle/reuse

Values of Natural Capital:

• Economic value: can be determined from the market price of the goods and services it produces.

• Ecological value: have no formal market price. Photosynthesis, nitrogen-fixation, soil erosion control are essential for human existence, but are taken for granted.

ECONOMIC vs ECOLOGICAL VALUE OF FORESTS

ECONOMIC VALUE 1. Fuel Wood2. Lumber3. Mining4. Livestock Grazing5. Recreation6. Jobs

ECOLOGICAL VALUE1. Energy and Chemical

Cycling2. Reduce Soil Erosion3. Purify Water4. Influence Climate5. Store Atmospheric

Carbon6. Wildlife

Habitat/Diversity

Advantages and Disadvantages of Clear Cutting

ADVANTAGES1. Higher Timber Yields

2. Max. profits in least amount of time

3. Can reforest with tree of choice

4. Good for species that need more light

DISADVANTAGES

1. Reduces biodiversity

2. Destroys/ Fragments habitat

3. Increases erosion/flooding

4. Eliminates Recreational value

Sustainable Forestry1. Identify and protect areas of high biodiversity

(Hot Spots)2. Rely more on selective cutting3. Don’t clear cut on steep slopes4. Don’t log old growth forests5. Reduce road building in uncut forests areas6. Leave dead and fallen trees for wildlife7. Plant tree plantations on already deforested

areas.8. Certify timber grown by sustainable methods9. Take Ecological value into account when

making forestry decisions.

Land Management

Public Land

- Owned by the Government

- 338 million Hectares = 835 mil. Acres

Private Land

- All land owned by individuals and companies.

National Park Service

Fish and Wildlife ServiceNational Wildlife Refuges

Bureau of Land ManagementNational Resource Land

U.S. Forest ServiceNational Forest