Management Strategies to Increase Structural Complexity and Enhance Biodiversity in Mixed Forests of Alaska, Japan, and central Europe

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1 Management Strategies to Increase Structural Complexity and Enhance Biodiversity in Mixed Forests of Alaska, Japan, and central Europe Robert Deal, USFS, PNW Research Station, Portland, OR USA T. Yoshida, Uryu Experimental Forest, Hokkaido, University, Japan M. Noguchi, Shikoku Research Center, FFPRI, Kochi, Japan Andrej Boncina, University of Ljubljana, Ljubljana, Slovenia Gabriel Duduman,, University of Suceava,, Romania

2 Overview Working Ho: Stands with greater complexity will have greater biodiversity then structurally simple stands. Few brief examples from Japan and Europe. Focus on two case studies from southeast Alaska. Potential solutions for management of both oldgrowth and younger forests. Synthesis of research.

3 Uniform, single-species plantation in Black forest

4 Multi-layered mixed species stands in Slovenia

5 Simple, uniform single-species plantation

6 Selectively harvested older stand in Scotland

7 Even-aged Hinoki plantations in Japan

8 Two storied Hinoki stands, Honshu, Japan

9 40 year old hemlock-spruce stand in SE Alaska Stem exclusion Greatly reduced biodiversity

10 40-year-oldalder-conifer stands, SE Alaska

11 Uneven-aged forests of Sitka spruce and western hemlock

12 Stand structure of old-growth forests

13 Even-aged forests

14 Reproduction following clearcutting Natural regeneration Dense uniform stands

15 Stand Development Stem exclusion Greatly reduced biodiversity

16 Stand development Stem exclusion Greatly reduced biodiversity

17 Wildlife Implications

18 Partial Cutting?

19 Concerns with Partial Cutting Changes in tree species composition. Residual trees of poor quality, low vigor. Increased dwarf mistletoe in hemlock. Increased wounding of residual trees. Windthrow is common.

20 Four Major Areas of Research Stand Structure and Growth Conifer Regeneration Patterns of Mortality, Wounding and Disease Plant Community Response

21 50-Year Year-Old Even-Aged Stand 1, Hemlock Spruce Trees/ha Diameter class (cm)

22 Trees/ha High-Site Partially Cut Stands 50 years since cutting Deal, Heithecker, Zenner, 2010 Hemlock Other Spruce Diameter class (cm)

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25 Hemlock stand 76 years after cutting

26 Spruce stand 85 years after cutting

27 Effects of Partial Cutting on Stand Structure and Plant Communities Current stand structure and growth is dominated by residual trees left after cutting. Size structure of partial cut stands (>50 yrs) was similar to uncut old-growth forests. Plant diversity very high in partially cut stands and similar to uncut stands. No significant changes in plant community structures following partial cutting.

28 Possibility of using silvicultural systems based on partial cutting in southeast Alaska We did not detect large changes in tree species composition, greatly reduced stand growth, increased hemlock dwarf mistletoe infection, or higher incidence of tree wounding, decay and mortality with partial cuts. Stand structural diversity, plant species diversity and abundance were all much higher than in young-growth growth stands developing after clearcutting.

29 Stand Dynamics of Mixed Red Alder-Conifer Forests of Southeast Alaska Robert Deal 1 Paul Hennon 2, Ewa Orlikowska 2, David D Amore 2 Pacific Northwest Research Station USDA Forest Service Portland, OR Juneau, AK

30 Forest vegetation Effect of increasing proportions of alder Stand development Stand structure Tree size distribution

31 Forest vegetation Effect of increasing density of alder: Understory plant biomass. Wildlife habitat.

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35 a) alder conifer Tree Density (Stems/ha) Diam eter Class (cm ) b) alder conifer Height Class (m )

36 Herbs Shrubs r2 =0.758 r2 = Percentage red alder Total net production (kg/ha)

37 Hanley et al, (CJFR, 2006) Deer days per hectare Summer Winter r2 =0.864 r2 = Percentage red alder

38 Summary and management implications Multiple food web components responding to red alder

39 Synthesis of Research Two potential solutions for increasing complexity, biodiversity. Partial cutting of older forests-focus on what stand structures are left, avoid high grading. In younger forests, encourage establishment of red alder and mixed broadleaf-conifer forests. Collaborative project in northern Japan, Alaska, PNW and central Europe