Forests & Grasslands Management
Chapter 10 Forests & Grasslands Management MANAGING AND SUSTAINING FORESTS
Instrumental Values of Forests: Fuelwood: 50% Timber/lumber:30% Pulp/paper:20% Figure 10-4 Types of Forests Old-growth forest: uncut or regenerated forest that has not been seriously disturbed for several hundred years. 22% of worlds forests. Hosts many species with specialized niches. Figure 10-5 Types of Forests Second-growth forest: a stand of trees resulting from natural secondary succession. Tree plantation: planted stands of a particular tree species. Figure 10-6 Rotation Cycles Short (fuel, paper) vs. long (hardwoods)
Even-aged management trees are same size, age (tree farms) Uneven-aged management different ages, sizes use selective cutting Figure 10-7 Harvesting Trees Building roads creates: 1) fragmentation,
2) habitat destruction 3) exotic species introduction 4) degradation. Figure 10-8 Methods of Harvesting Trees
1) Selective Cutting take intermediate to mature trees gaps are no larger than the height of the trees 2) Clear cutting take them all 3) Strip cutting cut strips along the contour of the land Figure 10-9 4) High grading take out largest/best specimens (also take out other trees actually removes 50% - cut the best, leave the rest) 5) Shelterwood takes out mature trees in 2-3 cuttings over 10 years prevents crowding 6) Seed-tree leave only a few to reproduce the forest Harvesting Trees Effects of clear-cutting in the state of Washington, U.S. Figures and 10-11 Forest Pathogens Fungal Chestnut blight, Dutch Elm disease
Insects Bark beetles (pines), Hemlock wooly adelgid Goals of Sustainable Forestry
1) Establish economic value of ecological services 2) Establish longer rotations in tree cutting 3) Protect old-growth and vulnerable areas 4) Certify sustainably grown trees 5) Minimize fragmentation of forests 6) Improve road building through forests 7) Leave snags for habitat Figure 10-12 CASE STUDY: FOREST RESOURCES AND MANAGEMENT IN THE U.S.
U.S. forests cover more area than in 1920. Since the 1960s, an increasing area of old growth and diverse second-growth forests have been clear-cut. Often replaced with tree farms. Decreases biodiversity. Disrupts ecosystem processes. Effects of Forest Fires & Types
Advantages - Burn away flammable ground material & release valuable mineral nutrients. Types:Surface only burns undergrowth, leaf litter Crown leaps from treetop to treetop Figure 10-13 Controversy Over Fire Management
Approaches to Fire Control: 1)Prescribed burns. 2) Allow fires to burn on public lands if they dont threaten life and property. 3) Clear small areas around property subject to fire. 4) Total supression. Controversy Over Fire Management
In 2003, U.S. Congress passed the Healthy Forest Restoration Act: 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. Reducing Demand for Harvest Trees
Use alternatives to wood for paper/pulp/ fuelwood (Kenaf (jute), bamboo, hemp) Figure 10-15 Forests in a Globalized Economy
Timber from tree plantations in temperate and tropical countries is decreasing the need for timber production in the U.S. Hot Spots areas with high biodiversity but have imminent danger of losing it (25 worldwide) Conservation Easement organizations compensate poor areas for protecting selected areas (debt-for-nature swaps) Buffer zone creation large area around a core of protected area MANAGING AND SUSTAINING GRASSLANDS
of worlds livestock graze on natural grasslands (rangelands) & managed grasslands (pastures) Figure 10-21 MANAGING AND SUSTAINING GRASSLANDS
Example of restored area along the San Pedro River in Arizona after 10 years of banning grazing and off-road vehicles. Figure 10-22 Case Study: Grazing and Urban Development in the American West
Ranchers, ecologists, and environmentalists are joining together to preserve the grasslands on cattle ranches by: 1)Paying ranchers conservation easements (barring future owners from development). 2)Pressuring government to zone the land to prevent development of ecologically sensitive areas. Types of US Public Lands
Multiple-use Lands:National Forests, National Resource Lands used for logging, mining, grazing, farming, oil, recreation provide a secure domestic supply of energy & strategic minerals Moderately-restricted use lands:National Wildlife Refuges can hunt, fish, mine, log, military Restricted-use lands:National Parks, Wilderness only for camping, hiking, fishing, boating no roads, logging, vehicles, grazing unless it predates designation Stresses on U.S. National Parks
1) Overused 2) Inholdings (private ownership) within parks threaten natural resources. 3) Air pollution 4) Exotic species 5) Too small to maintain biodiversity 6) Poaching Figure 10-23