AP ENVIRONMENTAL SCIENCE Unit 4: Forests, Parks, and Landscapes (Ch. 13)

Landscape Concept Landscape Perspective The concept that effective management and conservation recognizes that ecosystems, populations and species are interconnected across large geographic areas Within geographic areas there are also microclimates that vary greatly to support the large biodiversity of species and their niches

Modern Conflicts over Forest Land and Resources Silviculture: the professional growing of trees Forests benefit people through public service functions: functions performed by ecosystems for the betterment of life and human existence (Ex: cleansing of air by trees)

Modern Conflicts over Forest Land and Resources Debated questions: Are they used only as a resource? Are they used to conserve natural ecosystems and preserve biodiversity? Can a forest do both at the same time and place? Can a forest be managed sustainably for these uses? How? What other purposes can forests fill for people? (recreation, etc.) What role do forest play in our global environment?

Life of a Tree How a Tree Grows Photosynthesis, Transportation Systems, Evapotranspiration Growth occurs in two ways: Apical: increase in the length of the plant through vertical growth Trees exhibit apical dominance where one meristem (area of cell growth) dominates over others making one central trunk that increases the height of the plant The crown of a tree is where the apical growth takes place Lateral: increase in the width of the plant through the lateral expansion Results in branching or the development of tree rings

Life of a Tree Transportation of materials: Xylem: transportation of water upward to the leaves through capillary action (inside) Water is removed by evapotranspiration from the leaves in the crown allowing more water to be drawn up from the lower sections of the tree Phloem: transportation of organic food materials from the leaves to the roots (outside)

What is in a forest? Emergent: birds, invertebrates, bats Canopy: birds, reptiles, amphibians, lichens, mosses Understory: shade-tolerant plants, birds, squirrels, lizards, chipmunks Floor: rotting debris, worms, insects, bacteria Subsoil: nematodes, microorganisms

Tree Niches Determined by Water content in the soil Forest tolerance of shade There is no single best set of conditions for a forest

Forester’s View of a Forest Stand: group of trees Commercial stands are divided into even-aged and uneven- aged stands based on the diversity of development within the group Old-Growth Forest: a forest that has never been cut Frontier forests that have been uncut or not seriously disturbed for hundreds of years Second-Growth Forest: has been cut and re-grown Results of secondary succession

Forester’s View of a Forest Foresters group trees into: Dominants (tallest, most common, most vigorous) Codominants (fairly common species sharing the top of the canopy) Intermediate (layer of growth beneath dominants) Suppressed (growing in the understory) Sites are classified by site quality: the maximum timber crop the site can produce in a given time

Forest Management Clear Cutting: the cutting of all trees in a stand at the same time 4 Alternative Strategies: 1. Shelterwood-Cutting (cutting out dead and less desirable) 2. Seed-Tree Cutting (leaving mature, desirable seed trees) 3. Selective Cutting (thinning) 4. Strip-Cutting (leaving wooded “corridors”)

Experimental Tests of Clear-cutting Trees left standing provide shaded ground that slows decay and allows for absorption of nutrients from the soil Trees removed speed decay and erosion meaning run-off increases

Plantation Forestry Plantation: a stand of single species planted in straight rows Much like modern agriculture Properly managed plantations can relieve pressure on forests A small percentage of forest land could provide the world’s timber if managed properly

Sustainable Forestry 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. “certification of sustainable forestry” involves Determining which methods appear most consistent with sustainability Comparing the management of a specific forest with those standards This is hard to prove because tree growth is typically slow

Global Perspective on Forests How vegetation affects the atmosphere 1. Changing color of the 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 Earth’s surface into the atmosphere 4. Changing the “surface roughness,” which affects wind speed at the surface

Global Perspective on Forests In 2000 the world contained: 14.7 million square miles of forests (26.6% of the surface) Historical forest land by the numbers 1950 – 25% of the land surface million square miles million square miles From the agriculture revolution to 1950 there has been a decrease in almost half of the worlds forests. This prompted closer looks at forest conservation methods.

Global Perspective on Forests Forests with 50% tree cover occupy the largest area of forest land Tropical 47% Boreal 33% Temperate 11% Subtropical 9%

Global Perspective on Forests Since 1950 demand for wood products has doubled in size. Developed countries account for 70% of the worlds production and consumption of industrial wood (U.S. is the biggest importer) Developing countries use 90% of wood produced for firewood Construction, pulp and paper makes up 90% of the world’s timber trade which equals approximately 1.5 billion m 3 per year

Global Perspective on Forests In the United States: 75% of the commercial timber land is on the East coast 70% is privately owned 15% is U.S. Forest Service Land 15% is Federal Land

Global Perspective on Forests The world trade on timber has stabilized in recent years Fundamental Questions: How can the Earth’s forests continue to produce at this rate? Can production increase as population growth leads to higher demands? Can forest ecosystems remain sustainable?

Deforestation Cutting forests has more than just local effects on ecosystems Increased soil erosion is responsible for the loss of soil worldwide Increased soil erosion has led to increased deposition in stream channels that then makes flooding more likely There are discrepancies about whether or not the number of trees has actually decreased despite the negative effects of deforestation

History of Deforestation History of deforestation goes back to early civilization and the Roman Empire Cutting of forests followed the path of population spread into Northern Europe and then into North America with colonization Today deforestation occurs mainly in developing areas like the tropics, mountainous regions or high latitudes that could not be cleared before modern equipment was developed

World Firewood Shortage 63% of the wood produced in the world is used as an energy source in firewood Firewood accounts for 2% of the total commercial energy in developed countries but 15% in developing regions Firewood stands in developing countries lack proper management to continue to meet demands in the future

Indirect Deforestation Some loss of forests comes from indirect causes not associated with cutting Causes of indirect deforestation include: Pollution (including acid rain) Climate change Pathogens and Insects

Indirect Deforestation Pathogen and insect infestations in tree stands Bark BeetleSpruce Budworm Gypsy Moth Larvae Hemlock Woolly Adelgid Dutch Elm Feed and breed within living and dead phloem tissue. Feeds on spruce and fir needles and buds. Feeds on the leaves of deciduous trees Aphid-like insect that feeds on stored starches in the young twigs of hemlock trees Fungal disease affecting elm trees spread by the bark beetle.

Land Uses World land use

Land Use United States land use

Land Uses United States Land Ownership Federal lands 20% oil reserves 30% natural gas reserves 40% commercial forests Other mineral reserves

Multiple Use Lands National Forest System Managed by the U.S. Forest Service 156 forests, 22 grasslands Uses include logging, mining, grazing, farming, oil & gas, hunting, etc.

National Resource Lands Managed by the Bureau of Land Management (BLM) Emphasize secure supply of domestic energy, strategic minerals and preserving grazing under a permit system

Moderately Restricted Use Lands 525 National wildlife refuges Managed by the U.S. Fish and Wildlife Services Protects habitats and breeding grounds for waterfowl and big game so hunters have a harvestable supply Allows some hunting, trapping, oil & gas, mining, logging, farming as long as the Department of the Interior finds uses compatible for the land

Restricted Use Lands 385 units of the National Parks System 55 major parks that only allow camping, hiking, and sport fishing Vehicles are only allowed on park roads National Wilderness Preservation System Designated areas within parks that are roadless 42% of the National Park System, 33% Forest Service, 20% Fish and Wildlife Services

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 Must be careful not to create biogeographical islands

What is the goal of forest conservation? Preserve biological hotspots that support rich biodiversity 35 identified regions covering 2.3% of the Earth’s surface Contain a diversity of plants and animals not found anywhere else Threatened to the point that they contain 30% or less of their natural vegetation Largely forests

What is the goal of forest conservation? Preserve the 5 remaining frontier forests Rainforests in the Amazon, Central Africa and New Guinea Temperate Coniferous forests of North America, Russia and Scandinavia

What is the goal of forest conservation? Cease all logging in old-growth forests Restore lakes and rivers Make conservation profitable (Natural Capitalism) Promotes methods like agroforestry that incorporate trees into profitable agriculture