A Health Management Plan for Sitka Spruce

1. A Health Management Plan for Sitka Spruce By: Jeremy Greenwood April 27, 2007

2. Management Objective • Focus will be on southeast, Alaska • Management objective will be timber production but on a multiple-use forest (Tongass National Forest) 2 1

3. Introduction to the Species • Sitka spruce (Picea sitchensis) • Prominent along northwest coasts of N. America • Stands have some of the highest growth rates in NA • Commercially valuable species for lumber, pulp, & specialty uses • World’s largest spruce • Large individuals yield 6-8MBF. • Typical heights are 180’-200’ and DBH of 4’ to 5’ (max. is 315’; 19’) 3 Photo: J. Greenwood

4. 5 4 8 7 How to identify • Needles • 5/8”-1” long, flattened, yellow-green above, blueish white below, sharp pointed, R. angles from all sides of twig • Cones • 2” to 3.5”, fall in late autumn/early winter, thin & papery scales • Twigs • Orange-brown, with ovoid buds • Bark • Thin, silvery gray to purplish gray elliptical scales • Form • Long, cylindrical boles with short, open crowns. Branches are pendulous Source: Hardin, J.W., D.J. Leopold & F.M. White. 2001. Harlow & Harrar's Textbook of Dendrology-9th Ed. McGraw-Hill. 534 p. 6

5. Tree Species Adaptations • Climate • Coastal Species that is tolerant of ocean spray • Wide range of precipitation rates • 25” to 221” of precipitation • 0.5” to 134” of snow • Moisture is year round & abundant • Mild winters & cool summers • Frost free days range from 295 days in OR to 111 days in Cordova, AK

6. Tree Species Adaptations • Soils • Competes best on alluvial soils, sandy/coarse-textured soils or soils with lots of organic matter • Soils with large amounts of calcium, magnesium & phosphorus • pH ranging from 4 to 5.7 (acidic)

7. Tree Species Adaptations • Competition • Tolerant to intolerant • Develops best in gaps • Long-lived (up to 800 yrs) • Competitors include: • Western hemlock • Mountain hemlock • Western redcedar • Alaska cedar • Also several HW species (red alder, Sitka alder, & black cottonwood)

8. Wind: An Abiotic Stress 9

9. Wind: An Abiotic Stress • The most dominant disturbance agent in southeast Alaska • 27% of annual timber loss on the Tongass NF is due to wind • Little is known of the disturbance regime of Alaska in comparison to other regions where Sitka spruce is found (OR, WA, etc.) • Large storm systems in the fall • Development • Return interval (8 years) • Wind direction

10. Wind • Environment • Found throughout the range of Sitka spruce but ranges from single trees to large-scale blowdown • Highest intensity on hill tops/ridges • Lowest intensity on stands on north or northwest facing slopes

11. H:D Ratios • Useful measure of tree stability • Measure each dimension in same units (feet) • The higher the ratio the more unstable the tree becomes Wind • Predisposing Factors • Tree Adaptations • Height:Diameter ratios • Vigor • Quantity of crown

12. 12 Phellinus pini Wind: Predisposing Factors • Heart Rot Fungi • -Primary factors leading to stem snap • -Transport mechanism 11 10

13. 13 Wind • Degree of Stress • Time of year • Quantity of soil • Water holding capacity of soil • Sitka spruce rooting habits 14

14. Wind • Inciting Factors • Strong wind events such as gales • Wind speed (up to 100 mph) • Storm characteristics • Counterclockwise spin (cyclone) • Wave development in Gulf of Alaska • 24 to 30 hour notice prior to storms reaching landfall

15. 16 18 17 Wind Effects • Tree response • Wind snap • Wind throw • No Effect

16. Wind • Contributing Factors • Bark beetles • Fire 19 22 21 20

17. Wind: Control Options • Preemptive • Match silviculturalmethod to site • Stand replacing wind events=clear cut • Individual tree/Small gap windthrow= selection cuts • Increase species diversity

18. Wind Control Options (cont’d.) • Thin to foster high H:D ratios • Layout strip cuts in orientation to the prevailing winds 23

19. Wind Control Options • Reactive • Salvage harvest • Potentially controversial (Donato & Biscuit Fire) • No harvest action • Risks associated with no harvest 24

20. Wind Control Options: Feasibility • Preemptive measures are more cost effective than reactive measures • Difficulties with salvage harvests in this region • Political • Terrain

21. Spruce beetle(Dendroctonus rufipennis) 24 25

22. Spruce beetle Identification • Adults • dark brown w. reddish brown wing covers • Cylindrical; ¼” long by 1/8” wide • Can be confused w. Ips beetles (wing covers are evenly rounded on D.r.) • Eggs • Oblong, white, 1/16” long • Larvae • Cream colored legless grubs; ¼” at maturity • Pupae • Opaque white, inactive, similar size/shape to adults 26 27

23. Spruce beetle 28 • Life Cycle • Varies due to temperature (1 to 3 years) • Adults emerge from May thru October • Most attacks occur in early summer • Females bore into tree & create egg galleries (2.5”-12”) • 4 to 14 eggs/centimeter • Eggs hatch in August; Larvae bore out and feed as a group for the 1st two instars; the 3rd and 4th instars are characterized by individual galleries • Overwinter as Larvae (but eggs and parents can still be present) • Larvae pupate one year after attack (pupation lasts 10-15 days) • Overwinter as adults either in Larvael chambers or in the bark near the litter line (decreases predation by woodpeckers)

24. Spruce beetles • Signs • Red-brown boring dust on the ground • Entrance holes in the bark & crevices • Pitch at entrance holes (dependent on tree health) • Woodpecker activity on stems 29

25. Spruce Beetle Components • What is diseased in trees? • Feeds on multiple spruce species (including Sitka, Lutz, & white spruce) • Tissue functions affected are the phloem & cambium; foliage turns orange-red in the second year of infestation • Potential impact on whole tree functioning is dependent upon the population size of the beetles & tree health • Severe infestations create stands that are a complete loss

26. Spruce beetle • Tree Symptoms • None occur until the second summer of infestation • Needles turn yellow-green to orange-red • Needle drop due to wind/rain (leaving bare crowns) 30

27. Spruce beetle • Predisposing factors • Tree vigor & health (amount of pitch defense) • Slower than average growth rate=bad • Mature, large trees (increased food source) • Usually attack trees larger than 18” initially • Average stand diameter greater than 12” • Proportion of spruce in the stand • Stands with 70% or more spruce are highly vulnerable

28. Spruce beetle 31 • Inciting Factors • Any event that increases CWM • Harvesting • Wind events • Landslides

29. Spruce beetle • No important secondary/contributing factors • The beetles are quite capable of killing trees by themselves 32

30. Spruce beetle Control Options • Preemptive • Maintain stand health & vigor • Thinning • Minimize CWM over 12” • Minimize number of dominant trees in a stand

31. Spruce beetle Control Options • Reactive • Dependent on scale of outbreak & forest objectives • Rapid salvage harvesting focusing on dominant stems • Minimization of logging slash (chip/burn) • Antiaggregation Pheromones (as a control?) • Insecticides (Carbaryl & pyrethroids) 33 34

32. Health Management Plan • Preemptive • Monitor & Survey • Reactive • Feasibility

33. Preemptive Measures • In high value stands that are at risk • Antiaggregation pheromones (MCH) • Release must be properly timed to beetle flight • Minimize amount of CWM (over 12”) • Thinning from below to keep site vigor high and to increase component of wind-firm trees with high H:D ratios • Match silvicultural methods to site

34. Monitor & Survey • Aerial monitoring • Steep ground • Larger coverage area • Windfall monitoring should be done in spring due to winter storms, but after any major storm system monitoring should be encouraged • Bark beetle monitoring done in regions with lots of blowdown

35. Reactive Measures • A windthrown stand is likely to become infested therefore: • Salvage harvesting • Antiaggregation pheromones & pesticides in high value stands that are too immature to harvest or stands with high aesthetic value (recreation sites) • Trap Trees

36. Feasibility • Economic • Salvage quickly to ensure highest profit • Minimize spraying to high value stands • Ecological • Decreasing amounts of CWM • Decreased wildlife habitat • Political • Political opposition is likely with most salvage harvests • Be proactive in attempting to educate the public on the importance of salvage harvests (to the economy & to the forest)

37. Review • Sitka spruce • Management region: SE Alaska • Wind is the primary disturbance agent • Spruce beetles are the primary insect agent (linked with wind disturbance) • HMP Plan

38. Will I ever grow to be as old as Sitka spruce…? Questions? Photo by Thomas Magliery

39. Discussion Question • If you were a land manager in a region that had frequent stand replacing disturbances, what silvicultural method or methods would you use and why?

40. Discussion Question • You are a district ranger for the USDA Forest Service. Greenpeace is scheduled to make an appearance to your district. You have recently finished all of the necessary paperwork to conduct a salvage harvest on a 150 acre wind event. How do you think your guests will feel about this and how would you rationalize your timber crews actions?

41. Discussion Question • Jerry Franklin, a proponent of old-growth structures and CWM in forests, is coming to visit your forest. You have recently started a management policy to decrease the amount of CWM in your stands. How would you defend your actions?

42. Discussion Question • You are a landowner who has been tending a stand of highly valuable Sitka spruce for your lifetime. The USDA Forest Service is predicting massive spruce beetle outbreaks, what actions would you take?

43. Discussion Question • Does Sitka spruce relate to other things we have seen this semester and can we relate those management practices to this environment?

44. Discussion Question • You are a land manager for a large industrial company. The new, hotshot forester from New Zealand wants to implement pruning of Sitka spruce. Would you encourage or discourage his suggestion? Why?

45. Discussion Question • Given the few tree species in the region and the importance of Sitka spruce, what would happen if the climate regime changed and blowdown no longer occurred as frequently?

46. Photo Credits • Unless stated, the photos found in this presentation were taken by the author (J. Greenwood) • 1: http://www.alaskatours.com/alaskamap.jpg • 2: http://www.snowgoosealaska.com/images/ alaska-map-big.jpg • 3: Burns, R.M., & B.H. Honkala, tech. coords. 1990. Silvics of North America: 1. Conifers; 2. Hardwoods. Agriculture Handbook 654. U.S. Department of Agriculture, Forest Service, Washington, DC. vol.2, 877 p. • 4: Washington State Department of Ecology (http://www.ecy.wa.gov/programs/sea/coast/images/spruce_n2.jpg) • 5&7: Farrar, J.L. 1995. Trees of the Northern United States & Canada. Blackwell Publishing, Iowa. 512 p. • 6: BCadventure.com (http://www.bcadventure.com/adventure/wilderness/forest/sitka.htm) • 8: Cathedral Grove/British Columbia Archives: (http://www.cathedralgrove.se/text/01-Cathedral-Grove-3.htm) • 9:USGS http://vulcan.wr.usgs.gov/Volcanoes/MSH/Publications/MSHPPF/MSH_past_present_future.html • 10, 11, 16, 18, 19, 20, 21, 22, 25, 26, 29, 30, 31, 32, 33, 34: Forestry Images (http://www.forestryimages.org/) • 12: Hennon, P.E. 1995. Are heart rot fungi major factors of disturbance in gap-dynamic forests? Northwest Science. 69: 284-293. • 15: Mount Washington Observatory http://www.mountwashington.org/education/center/arcade/wind/beaufort.html • 17: Louis Morin • 13, 14, 23, 24 Harris, A.S.  1999.  Wind in the forests of southeast Alaska and guides for reducing damage. U.S. Department of Agriculture, Forest Service, Gen. Tech. Rep. PNW-GTR-244. 63 p. • 24, 27, 28: http://na.fs.fed.us/spfo/pubs/fidls/sprucebeetle/sprucebeetle.htm