1. Management of Hemlock-Spruce Forests for Multiple Values Michael McClellan Resource Management & Productivity Juneau Forestry Sciences Laboratory Pacific Northwest Research Station

2. Ten Important Questions Will partial cutting of old-growth maintain desired structures and functions, while creating a sufficiently productive new cohort of trees? Can we accurately predict tree and understory plant growth following partial cutting, clearcutting, and intermediate treatments? What are the processes by which young stands in southeast Alaska achieve old-growth overstory and understory characteristics, and can management influence this transition?

3. Are intermediate treatments (thinning, pruning, etc.) effective in maintaining or restoring understory plant diversity and abundance following clearcutting? How do existing and alternative silvicultural prescriptions affect the wood quality of young-growth stands? What are the effects of thinning, pruning, and other intermediate treatments on growth and yield?

4. Are variable-spacing thinning treatments effective in providing timber and non-timber values? Are the benefits worth the costs? What are the effects of extended rotations (≥ 120 years) on overstory and understory vegetation, with and without intermediate treatments such as thinning? How should evolving concepts of forest health affect our management of young stands? How do we best restore compositional and structural diversity in extensively harvested landscapes?

5. Potential additional axes: species mix, site productivity, stand age, etc.

6. TLMP-Associated Silvicultural Research Alternatives to Clearcutting in the Old-Growth Forests of Southeast Alaska (ATC) Forested Wetland Productivity Evaluation and Improvement of FVS-SEAPROG Effects of Silvicultural Treatments on Wood Quality Effects of Commercial Thinning on Understory Plants (Second-Growth Management Program, SGMP)

7. Alternatives to Clearcutting in the Old-Growth Forests of Southeast Alaska (ATC) ATC study began in 1994 and pre-dates the post-TLMP research program ATC is an integrated, long-term, operational- scale study that required significant cooperation between PNW and the Alaska Region to be implemented TLMP funding allowed the expansion of existing studies and the addition of new studies

8. Alternatives to Clearcutting: Collaborators & Topics Paul Hennon & Mike McClellan, PNW (damaging agents) Toni De Santo, PNW (bird communities) Mark Wipfli, PNW (stream ecology) Rick Woodsmith & Bob Erhardt, PNW (groundwater hydrology) Jeff Miller, Univ. Montana (social acceptance)

9. Study of Damaging Agents: How do ATC treatments and conventional clearcutting compare with regard to harvest- related and post-harvest damaging agents (e.g., wounding, decay, mistletoe, and wind damage)?

10. Key Findings: Pre-harvest Broken boles were the most common dead tree structures, followed by dead standing trees and uprooted trees Frequencies of dead trees within snag and log deterioration classes indicated that most trees died standing and subsequently broke Reconstructed annual mortality rates for overstory trees averaged 0.3 to 0.5% per year for the three locales and were relatively stable through the previous century

11. Key Findings: Post-harvest Group selection with gap diameters of 100 feet or less significantly increased reported problems during tree falling and yarding. Harvest-related damage to residual trees was greater at lower retention levels. Where 75% of the trees were left, generally fewer than 15% were damaged; when 25% of the trees remained, up to 40% were damaged to some extent. The spatial pattern of tree removal also affects damage to residual trees. Uniform retention led to a far higher rate of wounding of residual trees.

12. ATC Publications on Damaging Agents Hennon, Paul E.; McClellan, Michael H. 1999. Heart rot and other causes of small-scale disturbance in the temperate rain forests of southeast Alaska. In: Trummer, L., comp. Proceedings of the forty-sixth Western International Forest Disease Work Conference; 1998 Sep. 28- Oct. 2; Reno, NV. Anchorage, AK: U.S. Dep. Agric., For. Ser.: 97-105. Hennon, Paul E.; McClellan, Michael H.; Palkovic, Patricia. [In press] Comparing deterioration and ecosystem function of decay-resistant and decay-susceptible species of dead trees. In: Shea, P., ed. Symposium on the ecology and management of dead wood in western forests. Reno, NV. Nov. 2-4, 1999. Gen. Tech. Rep. GTR-PSW-###. Berkeley, CA: The Wildlife Society and USDA For. Serv., Pac. Southwest Res. Sta. Hennon, P.E.; McClellan, M.H. Tree death and its contribution to structure and chronic disturbance in temperate rain forests of southeast Alaska (submitted to Can. J. For. Res.)

13. Forested Wetland Productivity Collaborators Kent Julin, PNW Dave D’Amore, PNW Chris Meade, EPA Mike McClellan, PNW

14. Forested Wetland Productivity Two criteria for tentative suitability were not met: –sufficient data to ensure that timber production would not damage resources irreversibly –sufficient growth response data Sharply focused study: –Limited to Kaikli, Karheen, Kitkun, and Maybeso soil series –Did stands meet the wood production threshold for commercial forest land: a mean annual production rate of 20 ft 3 ·ac -1 ·yr -1 at CMAI?

15. Key Findings The stands were densely stocked with natural regeneration that grew slowly, yet predictably, during the first 50 years after clearcutting. Wood volume production ranged from 12 to 78 m 3 ·ha -1 for 15- and 46-year-old stands, respectively. Observed wood production rates in the first 50 years of stand development were consistent with estimates produced by the FVS-SEAPROG growth-and-yield model.

16. Observed & Predicted Growth on Forested Wetlands

17. Key Findings If the observed growth rates continue, these stands will exceed the USDA Forest Service wood production threshold for commercial timberland (20 ft 3 ·ac -1 ·yr -1 ) Based on the research findings, it was decided that it was no longer necessary to defer harvest on these four wetland soil types due to insufficient wood productivity

18. Additional Findings Forested organic soils were much deeper (>1 m) than indicated in soil resource descriptions and often existed as small inclusions within areas of better drained soils The observed range of fiber decomposition was broader than that described in the established Tongass soil classification system Aboveground vegetation was not a good indicator of wetland soil types, despite the heavy reliance on such characteristics in the Tongass Soil Survey

19. Forested Wetland Productivity Publications Sally Duncan. 2002. Soggy soils and sustainability: forested wetlands in southeast Alaska. PNW Science Findings, Issue 41. David D’Amore and Warren Lynn. 2002. Classification of forested Histosols in southeast Alaska. Soil Sci. Soc. Am. J. 66:554–562. Kent Julin and David D’Amore. [In press]. Tree growth on forested wetlands of southeastern Alaska. Western Journal of Applied Forestry. Planned: Hydraulic conductivity of peat soils in southeast Alaska

20. Evaluation and Improvement of FVS-SEAPROG Ultimate objective is to calibrate model for tree growth and yield following partial cutting and to add predictive capability for understory growth. Initial work has focused on improving model for young, even-aged, single-cohort stands In cooperation with the FMSC, improvements are underway to the mistletoe model and a wound size and frequency model is being added.

21. FVS-SEAPROG predicted trees per acre versus observed values from the Cooperative Stand-Density Study & Taylor plots

22. FVS-SEAPROG predicted quadratic mean diameter versus observed values from the Cooperative Stand-Density Study & Taylor plots

23. Key Findings FVS overestimates TPA from 200-1000 TPA. Estimated TPA plateaus at 2500-3000 TPA. For QMDs below 5 inches, FVS overestimates diameter. For QMDs of 10-25 inches, FVS consistently underestimates diameter. FVS tends to underestimate basal area; this is most pronounced when BA > 200-250

24. Key Findings FVS tends to underestimate cubic foot volume. This effect is worse at volumes > 6000-7000 cu. ft. FVS greatly underestimates board-foot volumes and this tendency increases at higher volumes.

25. Effects of Silvicultural Treatments on Wood Quality Methods for nondestructive evaluation of wood properties Thinning effects on: –wood mechanical properties (strength & stiffness) –wood density & early-wood/late-wood distribution –branch distribution, growth, & retention Pruning effects on: –epicormic branching –tree growth & mortality –understory plants

26. Wood Quality Collaborators Jamie Barbour, PNW Mike McClellan, PNW Bob Deal, PNW Bob Ross, Forest Products Lab Xiping Wang, Michigan Tech. Doug Maguire, Oregon State Bob Megraw, Weyerhaeuser Tech. Center

27. Pruning of Sitka spruce

28. Key Findings: Pruning Epicormic sprouts were common on spruce: –232 of 236 trees produced sprouts –9 to 11 sprouts per meter of tree bole The highest lift (5.2 m) produced significantly more large sprouts (≥3mm) Large, vigorous trees produce fewer large sprouts, making them better candidates for pruning Western hemlock did not produce sprouts

29. Key Findings: Pruning Tree height growth was similar among different pruning lifts Removal of 40% or more of the live crown significantly reduced tree diameter growth Speculation: Pruning may benefit understory plants by admitting more light to the forest floor than obtained through thinning alone

30. Wood Quality Publications Wang, X.; Ross, R.J.; McClellan, M.H.; Barbour, R.J.; et al. 2000. Strength and stiffness assessment of standing trees using a nondestructive stress wave technique. Res. Pap. FPL-RP-585. Wang, X.; Ross, R.J.; McClellan, M.; Barbour, R.J.; Erickson, J.R.; Forsman, J.W.; McGinnis, G.D. 2001. Nondestructive evaluation of standing trees with a stress wave method. Wood and Fiber Science, 33: 522-533. Deal, R.L.; Barbour, R.J.; McClellan, M.H.; Parry, D.L. Development of epicormic sprouts in Sitka spruce following thinning and pruning in southeast Alaska (submitted to Forestry) Planned: thinning and wood density, branch model, pruning effects on tree growth and understory plants

31. Effects of Commercial Thinning on Understory Plants (SGMP) Commercial thinning demonstration suggests benefits of individual-tree selection to understory plants and deer forage availability Wide spacing in precommercial thinning favored conifer regeneration—moderate spacing better for herbaceous vegetation

32. SGMP Publications Richard R. Zaborske, Richard N. Hauver, Michael H. McClellan, and Thomas A. Hanley. 2002. Understory vegetation development following commercial thinning in southeast Alaska: preliminary results from the Second- Growth Management Area Demonstration Project. In: Parker, Sharon; Hummel, Susan Stevens, eds. Beyond 2001: a silvicultural odyssey to sustaining terrestrial and aquatic ecosystems—proceedings of the 2001 national silviculture workshop, May 6-10, Hood River, Oregon. Gen. Tech. Rep. PNW-GTR-546. Portland, OR: U.S. Department of Agriculture, Forest Service, Pacific Northwest Research Station. p. 74-82.