Alternative Silvicultural Techniques for European Sub-alpine and Montane Protection Forests: Managing for community protection, disturbance resistance and resiliency, and timber production Harold Zald, Dept. Forest Science, OSU Chamonix, France

Protection forest overview Protecting from what? Protective functions Resistance and resiliency Protective attributes Alternative silviculture

Protecting from What? Protection from rockfall, avalanches, and debris flows Engineered mitigation is expensive!!! The role of forests in reducing rockfall increasingly appreciated

Protective functions, resistance, and resiliency Stability of protection forests over time requires managing for both resistance and resilience to rockfall and avalanche Direct-protection functions directly protect people, buildings, and infrastructure against the impacts of natural hazards such as rockfall and avalanches Site-protection functions protect the site a forest occupies against processes such as soil erosion and debris flows Resistance The ability of a protection forest to slow or dissipate the energy and matter generated in a rockfall or avalanche. Resilience The ability to recover direct-protection resistance characteristics following a natural hazard (or other) disturbance event.

Protection forest attributes: Stem Density Simulated rockfall patterns (rockfall accumulation in black) a) current forest, b) 50% stem reduction, c)100% stem reduction. Dorren et al Geomorphology Increased stem densities increase resistance to rockfall and avalanches

Protection forest attributes: Increased stem diameters increase resistance to rockfall and avalanches However importance of diameter varies Long live crowns

Protection forest attributes: Forest Floor/Understory Regeneration (for resistance and resiliency) Large down wood Shrubs Ground structure (rocks)

Alternative Silvicultural Applications Density/Size Management Developmental Stage Regeneration Understory/Forest Floor Management Silvicultural Application Layout Landscape Considerations

Density, Diameters, and Developmental Stages Greater resistance at the cost of lower resilience Implication: manage for earlier developmental stages Especially important for older Norway spruce plantations Best balance between resistance and resilience may occur at what is roughly analogous to the understory reinitiation stage - at the stand level

Ott 1989 Schonenburger For. Eco. Man. Regeneration Clumped planting Coppice method when possible Regeneration slits

Harvest Layout and Landscape Considerations Conserve forest floor structure Position harvest units with respect to hazards, areas to protect, and surround forests, non- forest vegetation, and any engineered mitigation structures Dorren et al For. Eco. Man.

When you look at these two forests, which is better for: Timber production? Protection function resistance? Protection forest resilience? Changing Objectives, Changing Perceptions