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Land and Water Use Part 2. Forestry Ecological Services 1. Providing wildlife habitat 2. Carbon sinks 3. Affecting local climate patterns 4. Purifying.

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Presentation on theme: "Land and Water Use Part 2. Forestry Ecological Services 1. Providing wildlife habitat 2. Carbon sinks 3. Affecting local climate patterns 4. Purifying."— Presentation transcript:

1 Land and Water Use Part 2

2 Forestry

3 Ecological Services 1. Providing wildlife habitat 2. Carbon sinks 3. Affecting local climate patterns 4. Purifying air and water 5. Reducing soil erosion 6. Providing energy and nutrient cycling

4 Tree Plantations  Large, managed commercial farm with uniformly aged trees of one species

5 Tree Plantations  Primary uses  Trees harvested by clearcutting

6 Tree Plantations  Species choice

7 Tree Plantations Pros Cons  Easy to harvest  Economical  More wood production  Little biodiversity  Damage to wetlands  Much smaller food webs  Little decaying wood

8 Old-Growth Forests  Have not been seriously impacted by humans  Much biodiversity

9 Old-Growth Forests  Depletion increases risk of climate change  High economic value, but mature slowly  Mahogany, oak

10 Old-Growth Forests

11 Forest Fires  Each forest is unique  Number of fires  Frequency of fires

12 Changes in Forest Fires  Wild fire frequency has increased (4X average )  Area burned has increased (7X previous)  Wild fire season lengthened by 78 days

13 Reasons for Changes  Appears to be linked to spring and summer temperatures  Fire management has changed

14 Crown Fires  Occurs where no fires have occurred in long time  Extremely hot  Burn entire tree  Hop from tree to tree  Kills wildlife, increases soil erosion, destroys structures

15 Yellowstone 1988

16 Ground Fires  Occur underground and burn partially decayed leaves  Common in peat bogs  Difficult to detect and extinguish  Summer Pocosin Lakes National Wildlife Refuge

17 Surface Fires  Burns undergrowth and leaf litter.  Kills seedlings and small trees  Releases minerals back into soil  Stimulates germination  Control pathogens and insects

18 Controlling Fires  Prevention  Prescribed burning

19 Deforestation  Conversion of forested areas to non-forested areas

20 Deforestation  Natural causes  Human reasons

21 Results of Deforestation

22 Methods to Manage and Harvest  Selective cutting  Strip cutting  Clear-cutting

23 Clear Cutting Pros Cons  Practical method for trees that require full or moderate sunlight  Genetically improved – resist disease, grow faster  Increased economic returns  Produces high yield of timber  Provides jobs  Reduces recreational value of the land  Causes soil erosion, water pollution, flooding on steeply sloped surfaces  Reduces biodiversity  Decaying wood is absent

24 Effect on Hydrologic Cycle  Decreased evapotranspiration  Lessens downwind precipitation  Increased runoff to rivers/ocean

25 Causes of Deforestation 1.Growing number of poor 2.“Open-access property rights” 3.Entrepreneurs

26 Forest Management  Forests cover 1/3 world land surface  Most forests in N. America, S. America, Russia  Forests cover 1/3 of US  2/3 nonfederal

27 Forest Management  Forest Service  1905  Agency of USDA  Manages public land in national forests and grasslands (193 million acres)  Logging, farming, recreation, hunting, fishing, mining, oil/gas extraction, livestock grazing


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