1. FOREST DISEASES AND FOREST HEALTH ESRM 101 Spring 2007 Bob Edmonds 264 Bloedel bobe@u.washington.edu

3. Alex Shigo

5. TOPICS 1. Natural disturbances in ecosystems 2. The concept of forest health 3. Causes of disease 4. Types of diseases 5. Impacts of tree diseases 6. Impacts of management on diseases 7. Management of diseases Great websites http://willow.ncfes.umn.edu/fhwebsites.htm http://www.pfc.cfs.nrcan.gc.ca/health/td_web/index.html

6. 1. Natural disturbances in ecosystems - caused by disease, fire, insects, wind, flooding, volcanic eruptions

7. Crown fire in interior west forests

8. Natural recovery of lodgepole pine forests 5 years after the Yellowstone wildfire. Note carpet of young seedlings.

9. Unhealthy forests in eastern Oregon and British Columbia - high mortality due to bark beetles and root diseases

10. 2. CONCEPT OF FOREST HEALTH Healthy people and individual trees do not have diseases, but healthy ecosystems can have dead and dying trees (important habitats for organisms

11. A healthy old-growth forest ecosystem in Mt. Rainier National Park Note dead trees (snags)

12. - a healthy ecosystem should be free from “distress syndrome,” where the syndrome is characterized by reduced primary productivity, loss of nutrient capital, loss of biodiversity, increased fluctuations in key populations, retrogressions in biotic structure, and widespread incidence and severity of diseases, insects and fires.

13. Dry Interior west Fire suppression high tree density drought stress root diseases bark beetles defoliators Unhealthy forest

14. 3. CAUSES OF DISEASE - non-biological (abiotic)- air pollution (0zone, acid precipitation), environmental conditions (too hot, too cold, too wet, too dry), nutrition - biological (caused by viruses, phytoplasmas, bacteria, fungi, parasitic plants (mistletoes), nematodes, amoeba) Fungi and dwarf mistletoes are most important in Pacific Northwest forests

15. ABIOTIC DISEASES

16. Dead trees at Clingman’s dome, Great Smoky Mountains National Park (left)and Mt. Mitchell, NC (below). Initially attributed to acid rain, but mostly due to the Balsam woolly adelgid Definitely unhealthy

17. Smog in southern California forests - mostly ozone produced by photochemical oxidation of NOx in auto exhausts

18. Ozone damage to ponderosa pine in California

19. Cold temperature injury

20. BIOLOGICAL DISEASES

21. Tobacco Mosaic virus

22. Camellia virus Camelia virus

23. Rod shaped bacteria

25. Mold fungus – Penicillium spores

26. Basidiomycete fungus – conk or fruiting body

27. True mistletoe on oak in California

28. Lodgepole pine dwarf mistletoe

29. Brooms on Douglas-fir caused by Douglas-fir dwarf mistletoe in eastern WA near Leavenworth

30. Root nematode Pine wilt nematode symptoms Pine wilt nematode

31. 3. TYPES OF DISEASES Foliage diseases Decay of stems and branches Rusts Cankers Wilts Dwarf mistletoes Root rots Wood stains

33. Defoliation from Swiss needle cast on Douglas-fir SWISS NEEDLE CAST - NATIVE DISEASE

34. Fomes fomentarius – white spongy trunk rot Hardwoods –birch, alder, poplar

35. Mortality in white bark pine caused by the introduced white pine blister rust.

36. Dutch elm disease Wilt disease Chestnut blight Canker disease BOTH ARE INTRODUCED DISEASES CAUSING LARGE-SCALE MORTALITY

37. Dwarf mistletoe male plants

38. Laminated Root Rot of Douglas-fir

39. Blue stain in pine

40. 5. IMPACTS OF DISEASES a. Mortality b. Reduced growth c. Destruction of merchantable wood (decay) d. Reduction in pulp yield e. Reduced wood quality - stain f. Delayed regeneration g. Inadequate stocking (trees/acre) h. Site deterioration - build up of pathogens i. Changes in species succession j. Creation of biodiversity

41. 6. IMPACTS OF FOREST MANAGEMENT ON DISEASES - Forest management has usually made diseases worse. e.g., thinning and clearcutting have generally increased root diseases, However, clearcutting and thinning decreased dwarf mistletoes Fire suppression has increased dwarf mistletoes and root diseases

42. 7. MANAGEMENT OF DISEASES 1.SILVICULTURAL - thinning, fertilization, stump removal for root diseases 2. CHEMICAL - foliage fungicide spraying 3. GENETIC - BREEDING FOR RESISTANCE/ BIOTECHNOLOGY - rust resistance 4. BIOLOGICAL CONTROL -stump treatment to prevent root disease 5. QUARANTINE - great concern about introduced diseases 6. DOING NOTHING

43. Stump removal for root rot management