Chapter 13 Forests, Parks and Landscapes Modern Conflicts over Forest Land and Forest Resources Do we use the trees as resources or conserve them? Can forests be managed sustainably for both? What role do forests play in the global environment? Use as a personal resource Earliest humans used wood for building and fuel Today the people in the world depend on wood for cooking In developing countries wood is the primary heating fuel. The effects of a forest Tree Niches Tree Niches Each sp. Of tree has its own niche Determined by Water content in the soil Tolerance of shade There is no single best set of conditions for a forest Also Some sp. Of trees may have specific germination requirements. Ie: fire or flood How a tree grows Forestry terminology Stand: group of trees of the same sp. Often in the same successional stage 2 Kinds: Even aged stands- all live trees began growth from seed & roots germinating in the same year Uneven aged stands- have at least 3 distinctive age classes of tree. A Foresters View of a Forest Old-Growth Forest: a forest that has never been cut Second-Growth Forest: has been cut and re- grown (rotation time: time between cuts of a stand) Foresters group trees into: - Dominants, Codominants, Intermediate and Suppressed Sites are classified by site quality: the maximum timber crop the site can produce in a given time Dominants- tallest, most common, share the canopy Codominants- fairly common, sharing the canopy Intermediate forms layer of growth below dominants Suppressed growing in the understory Parts of a forest Forest productivity Relies on: Soil fertility Water supply Local climate Managing Forests for Resource Removal of poorly formed or unproductive trees Planting of genetically controlled seedlings Fertilize soil Control diseases (fungus) Insects spread fungal diseases from tree to tree. Insect outbreaks are rare when they occur can devastate a forest. Insects defoliate trees, eat fruits and serve as carriers of disease. Define the following types of Clear-Cutting The cutting of all trees in a stand at the same time 4 types: 1. Shelterwood-Cutting 2. Seed-Tree Cutting 3. Selective Cutting 4. Strip-Cutting( Shelterwood cutting Cutting dead and less desirable trees first and later cutting mature trees Seed-tree Cutting Remove all but a few seed trees (mature trees with good genetic characteristics and high seed production. Promotes regeneration of forest Selective cutting Individual trees are marked and cut. Sometimes smaller, poorly formed trees are selectively removed called thinning Trees of specific sp. Or size are removed Effects of clear-cutting (before) Increased nitrogen levels in streams following logging Plantation Forestry Plantation : a stand of single species planted in straight rows Properly managed plantations can relieve pressure on forests Sustainable Forest Efforts to manage a forest so that a resource in it can be harvested at a rate that does not decrease the ability of the forest ecosystem to continue to provide that same rate of harvest indefinitely. 2 kinds of ecological sustainability: Sustainability of the harvest of a specific resource that grows with in an ecosystem Sustainability of the ENTIRE ecosystem In forestry, neither of these has been achieved 4 Ways Vegetation Can Effect the Atmosphere: 1. Changing color of the Earths surface and the amount of sunlight reflected and absorbed 2. Increasing the amount of water transpired and evaporated from the surface to the atmosphere 3. Changing the rate at which greenhouse gases are released from the Earths surface into the atmosphere 4. Changing the surface roughness, which affects wind speed at the surface Global Facts bill hectares forest covered 26.6% of the Earths surface. = 1 acre/person Down from 4.0 bill hectares in 1980 10 nations have 2/3 of the worlds forests Russia, Brazil, Canada, US, China, Australia, Congo, Indonesia, Angola, Peru Developed nations 70% of world production and consumption of industrial wood products. N.Amer. Dominant supplier. Deforestation History Causes World Firewood Shortage Indirect Deforestation History Before modern era forests where cut in Near East, Greece, and Roman Empire This continued northward into Europe as civilization advanced With the colonization of the New World, much of the N.Amer. Forests were cleared. Greatest loses are in S.Amer with 4.3 mill Acres lost per year since 2000 Why ??? Clear land for agriculture and settlement Use or sell timber for lumber, paper products or fuel Firewood Shortage 63% of wood produced in the world is used for firewood. Wood provides 5% of the worlds energy (2% in developed, 15% in developing countries, major source of energy in Sub- Saharan Africe, C.Amer, Southeast Asia ) As human pop. Increase, need for firewood increases. Indirect Deforestation Forests are lost, indirectly, from pollution and disease Acid rain, ozone, and other air pollutants can kill or weaken trees and make them susceptible to disease. Parks, Nature and Wilderness Wilderness: an area undisturbed by people Managing parks for biological conservation is a relatively new idea. Parks that are too small or in the wrong shape may not be able to sustain their species Parks and wilderness Copy Table 13.2 from textbook (pg 253) A Closer Look 13.2 A Brief History of Parks (pg 255) Critical Thinking Issue Can Tropical Forests Survive in Bits and Pieces? (pg 258)