1. Andreas Bolte, Peter Spathelf, Ernst van der Maaten Andreas Bolte 1, Peter Spathelf 2, Ernst van der Maaten 3 1 Thünen Institute of Forest Ecosystems, Eberswalde, Germany; 2 Eberswalde University for Sustainable Development, Dept. Forest and Environment, Eberswalde, Germany; 3 University Greifswald, Institute of Botany and Landscape Ecology, Greifswald, Germany IUFRO International Conference on Uneven-aged Silviculture, Birmensdorf / Switzerland 2014 Forest Adaptation and Close-to-Nature Silviculture (CNS) – coherence or contradiction?

2. Andreas Bolte, Peter Spathelf, Ernst van der Maaten Outline Vulnerability concept and status Close-to-nature silviculture (CNS) - principles Adaptive capacity CNS versus forest adaptation – coherence and conflicts Conclusions 18/06/20149th IUFRO International Conference on Uneven-aged Silviculture Page 2

3. Andreas Bolte, Peter Spathelf, Ernst van der Maaten Impacts of CC: Vulnerability concept Foto: M. Löf Foto: A. Bolte

4. Andreas Bolte, Peter Spathelf, Ernst van der Maaten Vulnerability concept 18/06/20149th IUFRO International Conference on Uneven-aged Silviculture Page 4 Exposure specifies the projected changes in climate affecting a system. Sensitivity describes the degree to which a system is responding to direct climatic and indirect (e.g. biotic) effects. Adaptive capacity describes the ability of a system to adapt to changes (e.g. climate). Vulnerability can be defined as the degree to which a system is susceptible to be affected by adverse effects of climate change. (cf. Lindner et al., 2010)

5. Andreas Bolte, Peter Spathelf, Ernst van der Maaten Exposures: Projected changes in dryness 18/06/20149th IUFRO International Conference on Uneven-aged Silviculture Page 5 Source: IPCC, 2012

6. Andreas Bolte, Peter Spathelf, Ernst van der Maaten Exposures: Standardized cyclone track density 18/06/20149th IUFRO International Conference on Uneven-aged Silviculture Page 6 Northern central Europe is often affected by storms; An increase in extreme wind intensities for this region is projected (Leckebusch et al., 2006). Source: Leckebusch et al., 2008 (p 76)

7. Andreas Bolte, Peter Spathelf, Ernst van der Maaten Increase of forest vulnerability (Europe) Increasing wood volume losses biased by record high standing volume in European forests? (cf. Bolte et al. 2009) 18/06/20149th IUFRO International Conference on Uneven-aged Silviculture Page 7 Source: Dobbertin & DeVries, 2008 (based on Schelhaas et al., 2003) Biotic attacs following storm and drought events are important drivers for tree and stand mortality. Windthrow Bark beetle attacks Exposure ↗ or Sensitivity ↗ ? Vulnerability?

8. Andreas Bolte, Peter Spathelf, Ernst van der Maaten Vulnerability - combined impacts (storm/drought) Total stock dynamics at Siggaboda nature reserve 2004 to 2011 18/06/20149th IUFRO International Conference on Uneven-aged Silviculture Page 8 Source: Bolte et al., 2014

9. Andreas Bolte, Peter Spathelf, Ernst van der Maaten Stand adaptation by succession from spruce to beech 18/06/20149th IUFRO International Conference on Uneven-aged Silviculture Page 9 Source: Bolte et al., 2010, 2014

10. Andreas Bolte, Peter Spathelf, Ernst van der Maaten Conceptual scheme of CC supported forest succession and stand adaptation 18/06/20149th IUFRO International Conference on Uneven-aged Silviculture Page 10 Source: Bolte et al., 2014

11. Andreas Bolte, Peter Spathelf, Ernst van der Maaten Some interim conclusions/hypotheses Storm, heat/drought, and accompanying biotic impacts are probably the most important exposures to CC of European forests. Several exposures/impacts interact with each other (e.g. storm damages, drought/heat waves and bark beetle infestations). Distinct disturbances (and not long-term CC effects) play a major role for CC-supported forest succession. The availability of tolerant, adaptable, or resilient tree species, populations, and specimens are essential for the vulnerability status of forest stands. 18/06/20149th IUFRO International Conference on Uneven-aged Silviculture Page 11

12. Andreas Bolte, Peter Spathelf, Ernst van der Maaten Close-to-nature silviculture - principles Foto: A. Bolte

13. Andreas Bolte, Peter Spathelf, Ernst van der Maaten Close-to-nature silviculture (CNS) Principles of CNS (Central European perspective, sensu: „Naturgemäße Waldwirtschaft“, cf. Pro Silva Principles 2012) Avoidance of clear-cuts Single-tree (and group) oriented interventions (no stand-scale!) Promotion of the natural and/or site-adapted tree species composition Promotion of mixed and ‘structured’ forests Promotion of natural regeneration Integration of forest ecosystem services (e.g. water, recreation) at small spatial scales  Aimed to mimicking small-scale disturbance regime 18/06/20149th IUFRO International Conference on Uneven-aged Silviculture Page 13 Source: Spathelf et al., 2014

14. Andreas Bolte, Peter Spathelf, Ernst van der Maaten CNS and silvicultural systems – a coherence? Regular and irregular shelterwood system (Femelschlag) acc. to Röhrig et al. (2006) 18/06/20149th IUFRO International Conference on Uneven-aged Silviculture Page 14

15. Andreas Bolte, Peter Spathelf, Ernst van der Maaten Some interim conclusions/hypotheses CNS (C-E style) is rather a ‘philosophy’ that a certain silvicultural system. CNS is tree-oriented (and groups as tree-competitor associations). CNS can be included in different silvicultural systems but it is rather difficult to ‘translate’ CNS into specific stand-scale silvicultural systems. It may be interesting to use the principles directly for evaluations. 18/06/20149th IUFRO International Conference on Uneven-aged Silviculture Page 15

16. Andreas Bolte, Peter Spathelf, Ernst van der Maaten Adaptive capacity (trees and populations) Foto: J. Müller

17. Andreas Bolte, Peter Spathelf, Ernst van der Maaten Adaptive processes (1) Long-term evolutionary adaptation -over one or more generations -due to selection processes (2) Phenotypic plasticity (acclimation) -ensuring short-term persistence of several years or a decade -due to individual alternation of plant morphology and/or physiology 18/06/20149th IUFRO International Conference on Uneven-aged Silviculture Page 17

18. Andreas Bolte, Peter Spathelf, Ernst van der Maaten Species range shifts and local adaptation (‘rear edge‘) 18/06/20149th IUFRO International Conference on Uneven-aged Silviculture Page 18 Source: Hampe and Petit, 2005

19. Andreas Bolte, Peter Spathelf, Ernst van der Maaten Beech distribution margins (North-eastern C-E) 18/06/20149th IUFRO International Conference on Uneven-aged Silviculture Page 19

20. Andreas Bolte, Peter Spathelf, Ernst van der Maaten Evolutionary adaptation of rear edge-populations (young beech plants!) 18/06/20149th IUFRO International Conference on Uneven-aged Silviculture Page 20 Source: Czajkowski and Bolte, 2006

21. Andreas Bolte, Peter Spathelf, Ernst van der Maaten Phenotypic plasticity of European beech (old-growth stand) Projected cumulative increment deviations (PCR scenarios, model CLIMTREG), European beech (Hainich National Park) 18/06/20149th IUFRO International Conference on Uneven-aged Silviculture Page 21 2 nd calibration period (1982-2006) 1 st calibration period (1957-1981) Source: Beck et al., 2013 Measured series 1 st calibration period 1957 to 1981 2 nd calibration period 1982 to 2006 Scenario based on 1 st calibration period Scenario based on 2 nd calibration period

22. Andreas Bolte, Peter Spathelf, Ernst van der Maaten Adaptive capacity to major CC impacts 18/06/20149th IUFRO International Conference on Uneven-aged Silviculture Page 22 Sensitivity to Phenotypic plasticity (individual level) Evol. Adaptation (population level) Succession / tree species change (species level) Heatlowmediumhigh Droughtmedium high Stormmedium high Biotic agentslowmediumhigh Totallow - mediummediumhigh

23. Andreas Bolte, Peter Spathelf, Ernst van der Maaten CNS versus forest adaptation – coherences and conflicts

24. Andreas Bolte, Peter Spathelf, Ernst van der Maaten Contradictory aspects of CNS and forest adaptation 18/06/20149th IUFRO International Conference on Uneven-aged Silviculture Page 24 Major CNS principles Phenotypic plasticity (individual level) Evol. Adaptation (population level) Succession / tree species change (species level) Single-tree or group management (no clear- cuts)o.K. Less light-demanding pioneer species Promotion mixed/structured forestso.K. Natural regenarationo.K. No assisted migration (provenances) No assisted migration (tree species) Natural tree compositiono.K. No assisted migration (tree species) 013

25. Andreas Bolte, Peter Spathelf, Ernst van der Maaten Tree species selection/changes prefered 18/06/20149th IUFRO International Conference on Uneven-aged Silviculture Page 25 Source: Spathelf et al., 2014

26. Andreas Bolte, Peter Spathelf, Ernst van der Maaten CNS and forest adaptation to CC – some conclusions CNS is a meaningful system (or ‘philosophy’) to support forest adaptation to CC mainly on tree (individual) and sometimes population level. However there are shortcomings when regarding the species level (promoting succession) by: the avoidance to introduce ‘neo-native’ tree species and provenances the promotion of mid- and late-successional species that limits the occurrence of stress-tolerant pioneer tree species. Thus, ‘active adaptation’ measures and ‘human-induced’ assisted migration are restricted. Thus, a strict application of CNS may limit the silvicultural options necessary for a successful adaptation of forest to CC. 18/06/20149th IUFRO International Conference on Uneven-aged Silviculture Page 26

27. Andreas Bolte, Peter Spathelf, Ernst van der Maaten Thank you for your attention!

28. Andreas Bolte, Peter Spathelf, Ernst van der Maaten References Beck, W.; Sanders, T.G.M.; Pofahl, U. (2013): CLIMTREG - detecting temporal changes in climate-growth reactions - a computer program using intra-annual daily and yearly moving time intervals of variable width. Dendrochronologia (in press). Bolte, A.; Ammer, C., Löf, M.; et al. (2009): Adaptive forest management in Central Europe - climate change impacts, strategies and integrative concept. Scand. J. For. Res. 24, 6: 473-482. Bolte, A. ; Hilbrig, L.; Grundmann, B. M.; Roloff, AS. (2013): Understory dynamics after disturbance accelerate succession from spruce to beech-dominated forest – the Siggaboda case study. Ann. For. Sci., DOI 10.1007/s13595-013-0283-y (Online) Czajkowski, T.; Bolte, A. (2006): Unterschiedliche Reaktion deutscher und polnischer Herkünfte der Buche (Fagus sylvatica L.) auf Trockenheit. Allg. Forst- u. J.-Ztg. 177: 30-40 (in German with English summary). Dobbertin M.; DeVries W (2008): Interactions between climate change and forest ecosystems. In: Fischer, R. (ed.) Forest ecosystems in a changing environment: identifying future monitoring and research needs. Report and Recommendations COST Strategic Workshop 11–13 March 2008, Istanbul, Turkey. http://www.icp-forests.org/pdf/COST.pdf. Accessed 07 April 2013. Hampe, A.;Petit, R.J. (2005): Conserving biodiversity under climate change: the rear edge matters. Ecology Letters 8: 461-467. Lindner, M.; Maroschek, M.; Netherer, S.; et al. (2010): Climate change impacts, adaptive capacity, and vulnerability of European forest ecosystems. Forest Ecology and Management 259: 698–709. Puettmann, K. Coates, K.D.; Messier, C. (2009) A critique of silviculture: Managing for complexity. Island Press, Washington, DC.,206 p. Spathelf, P.; Bolte, A. (in review): Is Close-to-Nature Silviculture (CNS) an adequate concept for adapting forests to climate change? Annals of Forest Science (in review) 18/06/20149th IUFRO International Conference on Uneven-aged Silviculture Page 28