Forest resilience is often cited as a management goal in a variety of silvicultural and forest ecology contexts. While the area of resilience theory is well developed, explicit metrics for the measurement of resilience are typically missing. We develop and describe a framework for operationalizing the resilience of forested systems. This conceptual framework is focused on enhancing the resilience properties of resistance to disturbance and recovery from disturbance. We outline four dimensions of resistance and recovery that can be used to measure and monitor resilience: heterogeneity at the patch scale, complexity at the multi-patch scale, quality of individuals and populations, and reserves of nutrients, carbon, and propagules. These dimensions are grounded in four core disciplines within ecology: community ecology, landscape ecology, population biology, and ecosystem ecology. We apply this framework to a northern hardwood forest system and quantify the effect of a nutrient addition on overall forest resilience. We also review studies (37 total) that have measured aspects of forest resilience in order to assess key measurements and analyses that can be used to quantify the four dimensions of resilience in the context of resistance and recovery.
Results/Conclusions
The novel resilience framework uses our best knowledge of theoretical resilience principles combined with management considerations to outline a comprehensive method for quantifying resilience. The innovation of this framework is to extend the scope of resilience measurements beyond heterogeneity and to be inclusive of ecosystem processes such as demography, competition, and nutrient cycling. The review of forest resilience papers demonstrated that holistic measurements of forest resilience are not out of reach. We found that a majority of the papers assessed resilience by measuring only recovery after disturbance (20 papers, 54%). Most papers (27 papers, 73%) measured the dimension of heterogeneity in order to quantify resilience, either measuring heterogeneity alone (11 papers) or in combination with another dimension (18 papers). Complexity was measured in 12 papers (32%) and reserves and quality were each measured to define resilience in nine papers (24%). These studies typically relied on measurements and analyses that are foundational to ecology and familiar to most ecologists and practitioners. We conclude that the challenge is not in inventing complex methods for measuring and analyzing resilience, but in identifying a comprehensive group of metrics that addresses the scope of the four resilience dimensions identified in the resilience framework described above.