Chapter 17 Land Resources

1. Chapter 17 Land Resources

2. Maximum Sustainable Yield • The maximum amount of a renewable resource that can be harvested without compromising the future availability of that resource.

3. Types of US Public Lands • Multiple-use lands: • National Forests – 156 forests and 22 grasslands managed by U.S. Forest Service. Used for commercial resource extraction, recreation, hunting and fishing. Limited use of Off-road vehicles. • National Resource Lands managed by Bureau of Land Management (BLM) – provides secure supply of energy and strategic minerals. – preserves rangeland which is dry, open grassland used for livestock grazing. • Moderately-restricted use lands: • National Wildlife Refuges – 524 refuges managed by USFWS. Protects habitats and breeding areas. Permits hunting, fishing, farming and resource development as long as its compatible. • Restricted-use lands: • National Park System – 398 parks managed by Dof Interior. Only camping, hiking, sports fishing & boating allowed. Off-road vehicles prohibited. • National Wilderness Preservation System – protects federally managed wilderness areas designated for preservation in their natural condition. Managed jointly by NPS (40%), Forest Service (33%), USFWS (19%) and BLM (8%).

4. Types of Forests • Old-growth (frontier) forests – have been undisturbed by humans or natural disasters for several hundred years. • Second-growth forests – stands of trees resulting from secondary ecological succession. • Tree farms/plantation – managed tracts with trees of one species and uniform age. They are harvested as soon as they become commercially valuable.

5. Ecological & Economic Services Provided by Forests Forests Figure 23-7 Page 600 Ecological Services Economic Services • Fuel wood (50% of Global use • Industrial Commercial Timber & Lumber • Pulp to make paper • Medicines • Mineral Extraction (Mining) • Livestock grazing • Recreation • Jobs • Support energy flow, food web and chemical cycling • Reduce soil erosion • Absorb and release water • Purify water • Purify air • Influence local and regional climate • Store atmospheric carbon • Provide numerous wildlife habitats U.S. forests: Cover about 30% of land area Provide habitats for more than 80% of the country’s wildlife species Supply about 2/3 of the nations runoff

6. Forest Structure, Ecological Niche • Biodiversity supported in ecological niches of old-growth forests

7. Forest Management • Rotation cycle – growth period required to derive desired value • Even-aged management – Method of forest management in which trees, sometimes of a single species in a given stand, are maintained at about the same age and size and are harvested all at once. • Uneven-aged management – Method of forest management in which trees of different species in a given stand are maintained at many ages and sizes to permit continuous natural regeneration. • Improved diversity • Sustainable production • Multiple-use

8. Management Strategies <= Rotation Cycle of a mono-culture tree plantation Harvest Cycle Time => A – Short rotation cycle for pulpwood or fuel B – Max wood yield / time C – High quality wood

9. Logging Roads • Increased erosion and runoff • Habitat fragmentation • Pathways for exotic & non native species • Accessibility to humans for other activities

10. Harvesting Trees • Selective cutting – 1) reduces crowding, 2) promotes younger growth, 3) maintains uneven age – diverse stand, 4) allows natural regeneration, 5) minimizes erosion, 6) removes diseased trees, and 7) enables multi-use • High-grading – largest, most desirable trees • Shelterwood cutting – only mature trees • Seed-tree cutting – leaves only few trees • Clearcutting – takes all trees • Strip cutting – alternating narrow strips over time

11. Timber Harvest Practices • Clear-cutting- removing all, or almost all the trees in an area. • Selective cutting- removing single trees or relatively small numbers of trees from a forest.

12. Sustainable Forestry • Longer rotations • Selective or strip cutting • Minimize fragmentation • Improved road building techniques • Certify sustainably grown

13. Sustainable Forestry • The stewardship and use of forests and forest lands in a way, and at a rate, that maintains their biodiversity, productivity, regeneration capacity, vitality and their potential to fulfill, now and in the future, relevant ecological, economic and social functions, at local, national, and global levels, and that does not cause damage to other ecosystems.

14. Fire Management • prescribed burns- a fire is deliberately set under controlled conditions.

15. Forest Fires Surface Fires Crown Fires

16. Forest Fire Management Occasional surface fires are beneficial because they: • Burn away flammable ground material preventing more destructive crown fires • Release valuable mineral nutrients in decomposing litter • Increase of underground nitrogen fixing bacteria • Stimulate the germination of certain tree seeds • Helps control pathogens and insects Four approaches used to protect forests from fire are: • Prevention • Prescribed burning (setting controlled ground fires) • Presuppression (early detection and control of fires) • Suppression (fighting fires once they are started) U.S. Park Services and the Forest Service set controlled prescribed fires in order to reduce the risk of more dangerous crown fires.

17. Forests • Forests – Areas dominated by trees and other woody vegetation • National Parks- established to preserve scenic views and unusual landforms. • National wildlife refuges- managed for the purpose of protecting wildlife • National wilderness areas- set aside to preserve large tracts of intact ecosystems or landscapes.