Resilient Forests, What Are They, Why Do We Need Them, and How Will We Get There.

Our next meeting will be at 6:00 pm on Tuesday September 6th at Turtle Rock Park.  Dr. Malcolm North of the Pacific Southwest Research Station of the U.S. Forest Service will be making a presentation on resilient forests, what they are under current and an anticipated warmer and drier future climate, why it is important, and what needs to be done so that our forests are resilient now and in the future.  This should be of particular interest to those that question the need to do something with the excess biomass in our forest.

Biography:  Malcolm North is a Research Forest Ecologist with the U.S. Forest Service Pacific Southwest Research Station, and an Affiliate Professor of Forest Ecology, Department of Plant Sciences at the University of California, Davis.  He received his Master of Forest Science at Yale University and his PhD in Forest Ecology from the University of Washington with Dr. Jerry Franklin.  Malcolm has worked on understanding many aspects of the ecology of Sierra Nevada forests, including the effects of fire suppression, carbon dynamics, ecosystem resilience and management constraints on increasing pace and scale and the broader use of fire.  He is also the lead author of the Forest Service publication GTR 220, an ecosystem management strategy for Sierran mixed-conifer forests.  A full list of his publications is available here.

Abstract:  With the increasing frequency and severity of altered disturbance regimes in dry, western U.S. forests, treatments promoting resilience have become a management objective but have been difficult to define or operationalize.  Many reconstruction studies of these forests when they had active fire regimes have documented very low tree densities before the onset of fire suppression.  Building on ecological theory and recent studies, I suggest that this historic forest structure promoted resilience by minimizing competition which in turn supported vigorous tree growth.  I assessed these historic conditions for management practices, by calculating a widely-used measure of competition, relative stand density index (SDI), for two extensive historical datasets and compared those to contemporary forest conditions.  Relative SDI for historical forests was 23-28% of maximum, in the ranges considered ‘free of’ (<25%) to ‘low’ competition (25-34%).  In contrast, most (82-95%) contemporary stands were in the range of ‘full competition’ (35-59%) or ‘imminent mortality’ (>60%).  These results suggest current fuel treatments may not be sufficient to restore resilience.  In particular there is a significant need to reduce tree density and restore forests to a low or no competition structure.  Current management practices often use competition to guide development of desired forest conditions.  Creating stands largely free of competition would require a fundamental rethinking of how frequent-fire forests should be managed for resilience.

Future Meetings:  Our October meeting may be cancelled if “Candidates’ Night” includes an educational session on Measure D.  Otherwise, it will be presentations on the role of biomass facilities in forest health, resilience, and air quality.   Please send suggestions for future speakers to  Presentations need to be on topics that relate to our mission statement.

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