Forestry

1. Forestry

2. Forests • Cover 1/3 of all land surface on earth • 80% = closed canopy • 20% = open canopy • 70% are in North America, Russian Federation, and South America • In USA • Largest land use category (1/3) • 747 million acres (500 million non federal) • Timbering in Pacific Northwest employees 150,000 people; $7 billion per year industry

3. Forestry • Management of forests • Involves • Planting new trees • Fires

4. Ecological Services of Forests • Providing wildlife habitat • Carbon sinks • Affecting local climate patterns • Purifying air and water • Reducing soil erosion • Forests serves as a watershed, absorbing and releasing controlled amounts of water. • Providing energy and nutrient cycling

5. Old – Growth Forests • Forests that have not been seriously impacted by human activities • Rich in biodiversity • Depletion of old-growth forests increases the risk of climate change • Many have trees that have high economic value but take a long time to mature • Mahogany, oak, etc.

6. Characteristics of Old-Growth Forests • Older and mixed-age trees • Minimal signs of human activity • Multilayered canopy due to tree falls • Pit-and-mound topography due to trees falling and creating new microenvironments by recycling organic material into the local environment and providing habitat • Decaying wood and ground layer that provides a rich carbon sink

7. Characteristics of Old-Growth Forests cont. • Healthy soil profiles • Indicator species – species that can tell about the overall health of an ecosystem • Little vegetation on the forest floor due to light being a limiting factor

8. Old Growth Forest22% of world’s forests

9. Secondary-Growth Forest63% of worlds forests

10. Tree Plantations • Large, managed farms with uniformly aged trees of one species • Trees may or may not be native to the environment • Trees are used for pulp or lumber • Pine, spruce, eucalyptus • Harvested by clear cutting

11. Tree Plantations cont. • Short rotation cycles • 25 - 30 years temperate zones • 6 – 10 years tropics • 5% of worlds forests but give 20% of current world wood production • Leading to conversion of forests to tree plantations • May result in draining of wetlands and replacing of traditional hardwoods

12. Tree plantation characteristics • Do not support food webs • Contain little biodiversity • Decaying wood is absent • Use of fertilizers and pesticides can harm the environment

13. Tree plantation – new stuff • New techniques leave some natural forest with in the plantation to provide a wildlife corridor • The Kyoto Protocol encourages use of tree farms as a carbon sink • Carbon may be released after harvesting

14. Examples of Tree Farms

15. Pros Practical method for trees that requires full or moderate sunlight to grow Efficient and economical method Genetically improved species of trees resist disease and grow faster Increases economic returns on investments Produces a high yield of timber at the lowest cost, provides jobs Cons Reduces the recreational value of the land Can cause soil erosion (on steep slopes), water pollution, flooding Causes habitat fragmentation Reduces biodiversity Promotes monoculture Tree plantations are prone to disease and infestation because of a lack of diversity Tree plantations

16. Forest Fires • Important ecological features • Clear out old and dead trees making room for new growth • Some trees need fires to germinate – conifers • Wildfire frequency is increasing • 4 times the average of 1970 – 1986 • Total area burned is 7 times the previous levels • Forest Service lengthened the fire season by 78 days

17. Fire basics Heat + Oxygen + Fuel source = Fire

18. Causes of Wildfire frequency changes • Climate change • changes in annual spring and summer temperatures • Longer, warmer summers • Early snow melt  earlier longer dry season • Changes in fire management philosophy • Old way: if there is a fire put it out NOW! • Lead to build up of flammable materials in the forest • New way: if fire is NOT threatening resources, let it burn

19. Types of Fires • Crown Fire: • Occur in forests that have not had a burn for a long time • Extremely Hot • Burn Entire Trees – leap from tree top to tree top • Kills wildlife • Increase soil erosion • Destroys structures

20. Types of Fires • Ground Fire: • Occur underground • Burn partially decayed leaves • Common in peat bogs • Difficult to detect and extinguish

21. Types of Fires • Surface Fire: • Burns undergrowth and leaf litter • Kills seedlings and small trees • Spares older trees – most animals escape • Advantages: • Burns away ground material, reducing larger fires • Release minerals back into soil • Stimulates germination of some seeds • Helps keep pathogens and insects in check • Allows vegetation clearing for animals

22. Methods of fire control • Prevention: • Burning permits • Closing parts of forest during drought and high traffic • Educating the public • Prescribed burning: Purposely setting controlled surface fires to thin out underbrush • Burn out: letting large fires burn themselves out

23. Question: Who should pay to protect these homes?

24. Deforestation • Conversion of forests into non forested areas • Natural: caused by tsunamis, forest fires, volcanic eruptions, glaciations, desertification • Human caused: land converted to • Livestock grazing • Grain fields • Mining • Petroleum extractions • Fuel wood cutting • Commercial logging • Tree plantations • Urban sprawl

26. Deforestation Results • Degraded environment • Reduced biodiversity • Reduced ecological services • Threatens loss of species with specialized niches • Decreases soil fertility • Reduces homes for migratory birds • Allows run-off into aquatic habitats • Changes in local climate patterns • Increases CO2 in the environment • Edge effects • Habitat fragmentation

27. Deforestation Results cont. • Alters hydrological cycle • Decreased amount of ground water • Increased flash flooding • Decreased evapotranspiration  less atmospheric moisture from rain • Loss of a carbon sink • Loss of tourist revenue

28. Causes of deforestation – schools of thought • Impoverished – believes that the major causes of deforestation is the growing number of poor people • Neoclassical – believes major cause is “open access property rights” • Political-ecological – believes major cause is entrepreneurs

29. Case Study: Hubbard Brook Experimental Forest • Centered on how deforestation affects nutrient cycles • Land: Forest with several watersheds each drained by a single creek, impervious bed rock close to the surface preventing seepage

30. Case Study: Hubbard Brook Experimental Forest

31. Case Study: Hubbard Brook Experimental Forest • Conclusions: • An undisturbed mature forest is a dynamic ecosystem • Inflow and outflow are balanced by nutrients entering and leaving the ecosystem • Deforestation lead to an increased water run-off • Nutrient loss could be limited by clearing forests in horizontal strips

32. Methods to manage and harvest trees • Even-age management: tree plantations • Uneven-age management: maintain a stand of trees from seedlings to mature trees • Selective cutting: specific trees are chosen and cut • High grading: cutting and removing only the largest and best trees • Shelterwood cutting: removes all mature trees in an area in a limited time

33. Methods to manage and harvest trees cont. • Seed Tree cutting: majority of trees removed except for scattered, seed producing trees used to regenerate a new strand • Clear-cutting: all of the trees in an area are cut at the same time. Sometimes used to cultivate shade-intolerant tree species • Strip cutting: clear-cutting a strip of trees that follows the land contour. The corridor is then allowed to regenerate

34. Forest Service • Established in 1905 as agency of US Department of Agriculture • 155 national forests, 22 grasslands • Manages 193 million acres (about the size of Texas) • Used for: logging, farming, recreation, hunting, fishing, oil and gas extraction, watersheds, mining, livestock grazing, farming, and conservation

35. Forest Service • Protects and manages natural resources • Provides community assistance • Cooperates with state and local governments, forest industries, and private land owners to mange resources • Provides international assistance in formulating policy and coordinating U.S. support for protection and management of world’s resources

36. Relevant Laws • Wilderness Act (1964): Created the legal definition of wilderness in the US. Currently 4 agencies (National Park Service, US Forest Service, US Fish and Wildlife service, and the Bureau of Land Management) are in charge of 106 million+ acres of federal wilderness • Wild and Scenic Rivers Act (1968): Preserves and protects certain rivers with outstanding natural, cultural, and recreational values in a free-flowing condition for the enjoyment of present and future generations. Classified rivers as wild, scenic, or recreational.

37. Assignment: • For each of the three schools of thought briefly design a management program to deal with deforestation based on the cause of deforestation for each school of thought. • Write these in your notes.