1. Ap Environmental Science
Unit 4: Forests, Parks, and Landscapes (Ch. 13)

2. 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

3. 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)

5. 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?

6. 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

7. 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)

9. 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

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

11. 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

12. 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

13. Forest Management Clear Cutting: the cutting
of all trees in a stand at the
same time
4 Alternative Strategies:
Shelterwood-Cutting (cutting out some mature trees but leaving others as shelter for saplings or to minimize erosion)
Seed-Tree Cutting (leaving mature, desirable seed trees)
Selective Cutting or Single tree harvesting (thinning)
Strip-Cutting or Group Selection (leaving wooded “corridors”)

14. 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

15. 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

16. Global Perspective on Forests
How vegetation affects the atmosphere
Changing color of the surface and the amount of sunlight reflected and absorbed
Increasing the amount of water transpired and evaporated from the surface to the atmosphere
Changing the rate at which greenhouse gases are released from the Earth’s surface into the atmosphere
Changing the “surface roughness,” which affects wind speed at the surface

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

20. 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 m3 per year

21. 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?

22. 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

24. 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

25. 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

26. 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

27. 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

28. Indirect Deforestation
Pathogen and insect infestations in tree stands
Bark Beetle
Spruce 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.

29. Land Uses
World land use

30. Land Use
United States land use

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

32. 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.

33. 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

34. 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

35. 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

36. 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

37. 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

38. 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

39. 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