Forest Dynamics : Growth, Loss, Regeneration

1. Forest Dynamics:Growth, Loss, Regeneration November 2004

2. Overview • Is deforestation real? • Why care about forests? • Forest functions and processes • Current research • Management strategies • Consumption practices

3. Stout Grove in Headwaters Forest

4. Is Deforestation Real?Headwaters Forest

5. Headwaters Forest

6. Headwaters Forest

7. Headwaters Forest

8. Humboldt State Park

9. Is Deforestation Real? • Who has the right answer? • Environmental Advocacy groups • Forest industry • Government Agencies • Scientists • With what time in the past do we compare the present?

10. Is Deforestation Real? Forest cover globally has declined from an estimated 62,203,000 sq km to 33,363,000 sq km (54% loss) in the past 8000 years. 4,500,000 sq km or 7% of the original cover lost between 1960 and 1990 Forest cover in Indochina is estimated to have declined from 70% in 1945 to 25% in 1995 Redwoods cover about 2 million acres in a coastal strip 5 to 35 miles wide from extreme southwest OR to around Big Sur. Cover has remained the same or perhaps even slightly increased but only about 74,000 acres of this is old growth-a 95% loss in old growth Many forest or old growth dependent species endangered or extinct: Coho Salmon, Marbled Murrlet, Spotted Owl

14. Remaining “Original” Forest (WRI)

15. World Forest Loss (WRI)

16. Human Footprint(Sanderson, Jaiteh, Levy, Redford, Wannebo, & Woolmer; BioScience 2002)

17. Forest Loss 1990-2000 (FAO)

21. Sources: Snyder 1992, Barbour et al. 1993, 2000 estimate by Willett

22. But there’s more trees now than ever! • Important forest characteristics include: • Density = number of trees per area • Frequency = how common • Dominance = how big • Diversity = how many kinds of trees • Structure = fallen logs, snags, understory • There may be more trees but that’s not all that’s important

23. Why care about forests? • Forests prominent in myth and religion as places of fear, enlightenment, and mystery • Hansel and Gretel experienced the forest as frightening • St. Hubert the Jagermeister received vision in forest • Odin crucified on the Tree of Life, Yggdrasil, an ash tree • Lord of the Rings • Buddha attains enlightenment under a tree • Generally, humans see forests as wild, magical places that must be tamed for civilization to progress

24. Buddhist Monks at Bodhi Tree(The site of Buddha's enlightenment)

25. Why care about forests? • Forests are beautiful • Over 3.5 million people per year from around the world visit Yosemite • Proximity to forest increases value of houses • Trees planted in urban settings such as streets and parking lots for aesthetic value but also reduce carbon monoxide pollution and temperature

26. Why care about forests? • Food • Nuts, fruits, roots, mushrooms, game, grubs • Medicine • Aspirin from willows • Taxol (anti-cancer drug) from Pacific Yew once removed from managed forests as a “junk” tree • Lady’s Slipper orchid, sedative, now endangered from habitat loss and over harvesting • Carbon fixation and reduction of earth’s albedo (reflectivity) influences global warming • Locally increases precipitation • Stabilizes soil with root structure • Habitat for game and non-game species

27. Why care about forests? • Wood • Fuel; wood is the primary heating and cooking fuel for most humans for most of our history including the present time • Fiber = rayon, paper (could use other plants) • Timber for homes, decks, fences, paneling, chopsticks, and toothpicks • Chemicals including turpentine and vanillin

28. Why care about forests? • Since ancient times, humans have protected certain forests or trees as sacred sites and for game and timber • Sacred groves of the Druids • King’s woods poached by Robin Hood • Select trees in the American colonies protected for use as masts in English naval vessels

29. Causes of Deforestation • Commercial logging • Clearing for agriculture such as coffee, bananas, pastureland for livestock • Mining • Oil and Gas Development • Hydroelectric dams • Housing development (often preceded by agriculture) • Cutting for fuel wood • Mechanization of logging • Increasing population and per capita resource use • Diseases and pests ie. Phytophtora ramora • www.suddenoakdeath.org • “Myth of Superabundance” -Udall, former Secretary of the Interior

30. Community Formation • Community = a group of associated organisms living in proximity at the same time • Succession = a change in species composition over ecological time, not speciation • Secondary Succession = succession that occurs after a catastrophe destroys a community but leaves soils intact ie. fire, flood • Primary Succession = succession that occurs after a catastrophe destroys a community and wipes out soils ie. glacier, volcanoes (Mt. St. Helens) • Seral stage = phase of succession such as early, mid, climax

31. Balsam fir, paper birch, and white spruce climax community Jack pine, black spruce, and aspen Heath mat Small herbs and shrubs Lichens and mosses Exposed rocks Time

32. Mature oak-hickory forest Young pine forest Shrubs Perennial weeds and grasses Annual weeds Time

33. Secondary Succession Grass  Shrub  Tree

34. Secondary Succession

35. Disturbance • Gradual • Minor fire • Tree falls • Herbivory • Disease • Catastrophic • Major fire • Flood • Glacier • Volcano • Huge comet smashing into the earth

36. Disturbance and Management • Patch Dynamics = Disturbances can create gaps in dominant trees that allow other species a chance to grow resulting in a greater variety of species • Many trees depend on fire to reproduce • Giant Sequoia (Sequoiadendron giganteum) • Knobcone Pine (Pinus attenuata) • These factors lead managers to allow or create disturbances such as “controlled” burns

37. Fire Management and Politics • Los Alamos, NM Park Service 2000 burn went awry • Wildfires of 2001-2002 and 2003 blamed on environmentalists accelerating “Healthy Forest Initiative” • "Past fire suppression is not to blame for causing large shrubland wildfires…Under Santa Ana conditions, fires carry through all chaparral regardless of age class. Therefore, prescribed burning programs … are futile at stopping these wildfires." -Dr. Jon Keeley, USGS fire researcher

38. Vertical Structure Canopy/Overstory Understory Shrub Herb Litter Root

41. Spatial Diversity

45. Temperate v. Tropical

46. Old Growth, Second Growth, Tree Farms • Old growth = mature forest not greatly disturbed by humans with native species composition and complete structural components; exact definition is controversial • Second Growth = regenerated forest following anthropogenic (human caused) catastrophe • Tree Farms = managed for timber, regularly disturbed

47. Clear Cut v. Select Cut • Clear cut = cutting all trees in an area and removing all cover • favors sun tolerant species • exposes soil to erosion • reforestation can fail • Select cut = cutting a selected portion of trees leaving much to little cover • Better preserves soil and genetic integrity • permanent roads • more frequent disturbances

48. Forest Symbioses Symbios = two organisms of different species where at least one affects the other’s resource acquisition or reproduction • Mutualism=both benefit (+ +) • Parasitism=one benefits, one suffers (+ -) • Commensalism=one benefits, other unaffected (+ 0) • Competition = both suffer (- -) • Amensalism=one suffers, other unaffected (- 0) • Neutralism=both unaffected (0 0)

49. Forest Symbioses • Most plants form mutualistic mycorrhizal (myc = fungus, rhiz = root) associations which aid growth and can even result in nutrient transfers between two different plant species connect to a common fungal associate

50. Forest Symbioses Examples • Trees, mushrooms, rodents, and bugs