Unit 4: Landscapes: Forests, Parks, and Wilderness Don’t miss the forest for the trees. There’s nothing wrong with having a tree as a friend. – Bob Ross Copyright © 2014 by John Wiley & Sons, Inc.
Copyright © 2014 by John Wiley & Sons, Inc. Forestry Silviculture—the professional growing of trees Developed into a science-based activity and into what we today consider a profession in the late 19th and early 20th centuries 1st modern U.S. professional forestry school was established at Yale University around the turn of the 20th century New slide Copyright © 2014 by John Wiley & Sons, Inc.
How Forests Affect the Earth Vegetation of any kind can affect the atmosphere in four ways By changing the color of the surface and thus the amount of sunlight reflected and absorbed By increasing the amount of water transpired and evaporated from the surface to the atmosphere Copyright © 2014 by John Wiley & Sons, Inc.
How Forests Affect the Earth Vegetation of any kind can affect the atmosphere in four ways (cont’d.) By changing the rate at which greenhouse gases are released from Earth’s surface into the atmosphere By changing “surface roughness,” which affects wind speed at the surface Copyright © 2014 by John Wiley & Sons, Inc.
Copyright © 2014 by John Wiley & Sons, Inc.
Copyright © 2014 by John Wiley & Sons, Inc. Ecology of Forests Each species of tree has its own niche It is adapted to specific environmental conditions Soil moisture level Tolerance of shade Stages of succession Copyright © 2014 by John Wiley & Sons, Inc.
Anatomy of Forests
Copyright © 2014 by John Wiley & Sons, Inc. The Life of a Tree How does a tree grow? Leaves take up carbon dioxide and absorb sunlight Water transported up from roots Leaves carry out photosynthesis Products = simple sugar and oxygen Roots have symbiotic fungi that help extract minerals from the soil Copyright © 2014 by John Wiley & Sons, Inc.
Copyright © 2014 by John Wiley & Sons, Inc. How a Tree Grows Leaves and roots connected by two transport systems Phloem Inside of the living side of bark Transports sugars and other organic compounds down to stems and roots Copyright © 2014 by John Wiley & Sons, Inc.
Copyright © 2014 by John Wiley & Sons, Inc. How a Tree Grows Leaves and roots connected by two transport systems Xylem Located farther inside bark Transports water and inorganic molecules upward to the leaves Sun-powered pump Copyright © 2014 by John Wiley & Sons, Inc.
Copyright © 2014 by John Wiley & Sons, Inc.
Anatomy of Leaf
Chlorophyll and Chloroplasts Photosynthesis takes place inside organelles called chloroplasts. Chloroplasts contain saclike photosynthetic membranes called thylakoids, which are interconnected and arranged in stacks known as grana.
Chloroplasts Pigments, such as chlorophyll, are located in the thylakoid membranes. The fluid portion of the chloroplast, outside of the thylakoids, is known as the stroma.
An Overview of Photosynthesis Photosynthesis uses the energy of sunlight to convert water and carbon dioxide (reactants) into high-energy sugars and oxygen (products). Plants use the sugars generated by photosynthesis to produce complex carbohydrates such as starches, and to provide energy for the synthesis of other compounds, including proteins and lipids.
An Overview of Photosynthesis Because photosynthesis usually produces 6-carbon sugars (like glucose) as the final product, the overall reaction for photosynthesis can be shown as follows: Although the equation looks simple, there are many steps to get from the reactants to the final products.
How People View Forests Traditionally appreciated for building material and fuel Today we appreciate them for public-service functions Erosion reduction Water supply improvement Endangered species and wildlife habitat Recreation, including hiking, hunting, and bird and wildlife viewing Climate stabilization Copyright © 2014 by John Wiley & Sons, Inc.
Copyright © 2014 by John Wiley & Sons, Inc. World Forest Area, Global Production and Consumption of Forest Resources At beginning of 21st century, 26% of Earth was forested 15 million square miles Approximately 1 acre per person Countries differ greatly in their forest resources Potential of their land and climate for tree growth History of land use and deforestation Copyright © 2014 by John Wiley & Sons, Inc.
Copyright © 2014 by John Wiley & Sons, Inc.
Copyright © 2014 by John Wiley & Sons, Inc.
Copyright © 2014 by John Wiley & Sons, Inc. World Forest Area, Global Production and Consumption of Forest Resources Developed countries 70% of production and consumption of industrial wood products Timber trade 90% for construction, pulp and paper 10% hardwoods for furniture Developing countries 90% of production and consumption of wood is for firewood Copyright © 2014 by John Wiley & Sons, Inc.
Copyright © 2014 by John Wiley & Sons, Inc. World Forest Area, Global Production and Consumption of Forest Resources Recent world trade in timber has not grown substantially Fundamental questions Can forests continue to produce the current amount of timber for an infinite period? Can forests produce even more as the population grows? Copyright © 2014 by John Wiley & Sons, Inc.
Modern Conflicts over Forestland and Forest Resources Who should own forests and their resources? The people? The government? Private organizations/companies? Should forests be used only for their material resources, or to conserve natural resources and biodiversity? Can forests be managed sustainably? What role do forests play in global environment? Copyright © 2014 by John Wiley & Sons, Inc.
Copyright © 2014 by John Wiley & Sons, Inc. U.S. Forest Ownership in 2008 Approximately 304 million hectares (751 million acres) of forests 86 million hectares (212 million acres) are considered commercial grade forest Commercial timberland occurs in many parts of the United States Nearly 75% is in the eastern half of the country About 25% in Alaska and the West (Oregon, Washington, California, Montana, Idaho, Colorado, and other Rocky Mountain states) New slide. Copyright © 2014 by John Wiley & Sons, Inc.
Copyright © 2014 by John Wiley & Sons, Inc. https://www.youtube.com/watch?v=rlleeID68Kc Copyright © 2014 by John Wiley & Sons, Inc.
Copyright © 2014 by John Wiley & Sons, Inc. Forest Management Forests managed in stands Usually comprised of trees of the same species and successional age Stands classified based on tree composition Even-aged stands Uneven-aged stands Copyright © 2014 by John Wiley & Sons, Inc.
Copyright © 2014 by John Wiley & Sons, Inc. Forest Management Forest that has never been cut is called: Virgin forest Old-growth forest Forest that has regrown after a cut is called: Second-growth forest Copyright © 2014 by John Wiley & Sons, Inc.
Copyright © 2014 by John Wiley & Sons, Inc. Forest Management Rotation time—the time between cuts of a stand Site quality—maximum timber crop the site can produce in a given time Copyright © 2014 by John Wiley & Sons, Inc.
Copyright © 2014 by John Wiley & Sons, Inc. Forest Management Foresters and forest ecologists group the trees in a forest into: Dominants Codominants Intermediate Suppressed Copyright © 2014 by John Wiley & Sons, Inc.
Copyright © 2014 by John Wiley & Sons, Inc. Harvesting Trees Managing forests that will be harvested may involve: Removing poorly formed and unproductive trees to permit larger trees to grow Planting genetically controlled seedlings Controlling pests and diseases Fertilizing the soil Copyright © 2014 by John Wiley & Sons, Inc.
Copyright © 2014 by John Wiley & Sons, Inc. Harvesting Trees Harvesting trees is done in many ways Clear-cutting—the cutting of all trees in a stand at the same time (pictured to the right) Selective cutting—individual trees are marked and cut (thinning) Copyright © 2014 by John Wiley & Sons, Inc.
Copyright © 2014 by John Wiley & Sons, Inc. Harvesting Trees Harvesting methods (continued) Strip-cutting—narrow rows of forest are cut, leaving wooded corridors whose trees provide seeds Shelterwood cutting—practice of cutting dead and less desirable trees first and later cutting mature trees Seed-tree cutting—removes all but a few seed trees to promote regeneration of the forest Copyright © 2014 by John Wiley & Sons, Inc.
The NFS promotes Forest Ecosystem Management (FEM), which includes less-disruptive harvesting techniques, as well as forest restoration and research.
When trees are harvested properly, they can provide immediate and long-term economic benefits without serious environmental damage.
Experimental Test of Clear-Cutting Scientist have tested the effects of clear- cutting in many locations Generally negative results arise Hubbard Brook experimental forest in NH Pattern of water runoff changed substantially Exposed soil decayed and eroded more rapidly Stream water exceeded public health standards for nitrates Copyright © 2014 by John Wiley & Sons, Inc.
Experimental Test of Clear-Cutting H.J. Andrews experimental forest in OR Increase in the frequency of landslides after clear-cutting Clear-cutting changes chemical cycling in forests and causes the soil to lose chemical elements necessary for life Copyright © 2014 by John Wiley & Sons, Inc.
Old-Growth Forest—Never Clear-Cut Copyright © 2014 by John Wiley & Sons, Inc.
Copyright © 2014 by John Wiley & Sons, Inc. Clear-Cut Forest Insert: Figure 12.9 Effects of clear-cutting on forest chemical cycling. Chemical cycling (b) after clear-cutting. Copyright © 2014 by John Wiley & Sons, Inc.
Stream Nitrate Levels Pre and Post Logging Copyright © 2014 by John Wiley & Sons, Inc.
Experimental Test of Clear-Cutting Experiments demonstrate Clear-cutting can be a poor practice on steep slopes in areas of moderate to heavy rainfall Clear-cutting on an appropriate spatial scale may be useful to regenerate desirable species On level ground With moderate rainfall When desirable species require open area to grow Copyright © 2014 by John Wiley & Sons, Inc.
Copyright © 2014 by John Wiley & Sons, Inc. Plantation Forestry Plantation—a stand of a single species typically planted in straight rows Much like agriculture Fertilizers added, mechanized harvesting Offer a solution to the pressure on natural forests High-yield forests could provide all the world’s timber Copyright © 2014 by John Wiley & Sons, Inc.
Copyright © 2014 by John Wiley & Sons, Inc.
Can We Achieve Sustainable Forestry? Two basic kinds of ecological sustainability Sustainability of the harvest of a specific resource within an ecosystem (harvest of timber) Sustainability of the entire ecosystem (forest as an ecosystem) Lack scientific data to demonstrate that either type has been achieved in forests Copyright © 2014 by John Wiley & Sons, Inc.
Certification of Forest Practices Compare the actual practices of a specific corporation or government agency with practices that are believed to be consistent with sustainability Inadequate knowledge if beliefs are correct or practices really sustainable Movement to call them “well-managed forests” or “improved management” rather than “sustainable” Copyright © 2014 by John Wiley & Sons, Inc.
Copyright © 2014 by John Wiley & Sons, Inc. Deforestation Deforestation is estimated to have increased erosion and caused the loss of 562 million hectares of soil Deforestation affects regions, not single countries Deforestation in one country can affect countries downstream E.g., Nepal and India Copyright © 2014 by John Wiley & Sons, Inc.
Copyright © 2014 by John Wiley & Sons, Inc.
Copyright © 2014 by John Wiley & Sons, Inc. Deforestation Some good news Rate of deforestation has slowed over the last 10 years, according to the United Nations Environment Program Every year only an area about as big as Costa Rica is deforested Copyright © 2014 by John Wiley & Sons, Inc.
Deforestation
Copyright © 2014 by John Wiley & Sons, Inc.
History of Deforestation Has occurred in all societies Early Greece and Roman Empire Prehistoric farmers in Denmark Medieval Great Britain Colonization of the New World The greatest losses in the present century have taken place in South America 4.3 million acres/year lost since 2000 Copyright © 2014 by John Wiley & Sons, Inc.
Causes of Deforestation Two most common reasons Clear land for agriculture and settlement Cut trees for use as timber for lumber, paper products, or fuel Copyright © 2014 by John Wiley & Sons, Inc.
Indirect Deforestation The death of trees from pollution and/or disease Acid rain Ozone Other air pollutants All can increase susceptibility to disease Global climate change may lead to Major die-off and shift in areas of potential growth Copyright © 2014 by John Wiley & Sons, Inc.
Copyright © 2014 by John Wiley & Sons, Inc.
Dealing with Forest Fires Fire is a repeated occurrence in most forests of the world Many tree species adapted to fire and many require fires for regeneration Fire suppression was the rule during 19th and much of 20th centuries Naturalness of forest fires studied by ecologists during late 20th century Copyright © 2014 by John Wiley & Sons, Inc.
Dealing with Forest Fires Many in government and the public sphere saw fires as only damaging, thus the then familiar poster of Smokey Bear and his slogan, “Only you can prevent forest fires” Notable forest fires Yellowstone Park, 1988 “Painted Cave Fire” of So. CA in 1990 Near Los Angeles, CA in 1993 Others even more recently in Colorado, New Mexico, Arizona, and Idaho Copyright © 2014 by John Wiley & Sons, Inc.
Dealing with Forest Fires It is well acknowledged that many kinds of forests require fire and that comparatively frequent light fires are characteristic and least damaging to forests Difficult to manage forests in the modern world due to so much human development—houses, towns, cities, farms, and industrial complexes Fire control project in Ponderosa pine forests near Flagstaff, Arizona Copyright © 2014 by John Wiley & Sons, Inc.
Copyright © 2014 by John Wiley & Sons, Inc.
Current Wild fires in California http://www.fire.ca.gov/current_incidents
Parks, Nature Preserves, and Wilderness Landscapes may be protected in different ways Government Parks Nature preserves Wilderness areas Private organizations Buy land and maintain it as nature preserves Copyright © 2014 by John Wiley & Sons, Inc.
Copyright © 2014 by John Wiley & Sons, Inc.
Copyright © 2014 by John Wiley & Sons, Inc. Parks and Preserves Park Area set aside for use by people Nature preserve May be used by people but primary purpose is the conservation of some resource Both create ecological islands Island biogeography used in design and management Copyright © 2014 by John Wiley & Sons, Inc.
Parks and Preserves as Islands The size of the park and the diversity of habitats determine the # of species that can be maintained The more isolated the park is from other parks or sources of species, the fewer species are found Copyright © 2014 by John Wiley & Sons, Inc.
Parks and Preserves as Islands Most park boundaries have been arbitrarily set and are not based on ecology For example, Lake Manyara National Park in Tanzania Original boundaries did not include entire elephants range Elephants and farmer came into direct conflict Boundaries were shifted to solve conflict Copyright © 2014 by John Wiley & Sons, Inc.
Conflicts Relating to Parks Major conflicts generally have to do with Size What kinds of activities and levels of access will be available Copyright © 2014 by John Wiley & Sons, Inc.
Conflicts Relating to Parks Major conflicts generally have to do with What intensity of activities, including Recreation Conservation of scenery Conservation of biological diversity Scientific research Conservation of specific endangered species or species of special interest Sites with kinds of DNA not found elsewhere that can be of considerable economic value Mining for oil and natural gas Use of water aquifers Copyright © 2014 by John Wiley & Sons, Inc.
How Much Land Should be in Parks? What percentage of the landscape should be in parks or nature preserves? Conservationists typically want to make parks bigger Commercial interests typically want to keep parks smaller If parks are to function as biological preserves, they must be adequate in size and habitat diversity Copyright © 2014 by John Wiley & Sons, Inc.
Conserving Wilderness As a modern legal concept, wilderness is an area undisturbed by people New idea introduced in the second half of the 20th century U.S. Wilderness Act of 1964 First time wilderness recognized by national law “Land retaining its primeval character and influence” Copyright © 2014 by John Wiley & Sons, Inc.
Conserving Wilderness Wilderness are lands in which: Imprint of human work is unnoticeable There are opportunities for solitude and primitive and unconfined recreation There are at least 5,000 acres The law also recognizes that these areas are valuable for ecological processes, geology, education, scenery, and history “Wilderness” versus “wildness” Copyright © 2014 by John Wiley & Sons, Inc.
Copyright © 2014 by John Wiley & Sons, Inc.
Conflicts in Managing Wilderness Legal definition given rise to several controversies Desire to include more land as wilderness Desire to develop this land and its natural resources Can view goal of managing wilderness in two ways To preserve nature undisturbed by people To provide people with a wilderness experience Copyright © 2014 by John Wiley & Sons, Inc.