Navigating Resilience

As the Resilience Programme of the European Forest Institute, we are looking for evidence-based ways to improve resilience in the European forests. However, a brief discussion in the office revealed that even among our staff there are almost as many interpretations of resilience as there are staff-members. We needed to have a clearer understanding on what resilience means in the context of forestry.
As part of Laura Nikinmaa's PhD, she embarked on a mission to find out what exactly does resilience mean. Therefore, she performed a systematic analysis in which she scanned through more than 2,600 abstracts of studies, ultimately ending with 255 articles for her review. Her findings were published recently in the journal Current Forestry Reports. Here we summarize the results of the research.

Overall, resilience is widely used in different scientific disciplines. In the literature studying forest ecosystems and forestry, three popular concepts exist:

• engineering resilience (Pimm, 1984)
• ecological resilience (Holling, 1973)
• social-ecological resilience (Resilience Alliance, 2019)

Engineering resilience is the time it takes for a system to recover to its pre-disturbance state. Ecological resilience is the capacity of the system to absorb the disturbance and still maintain its identity. Social-ecological resilience can be defined as the capacity of the social-ecological system to absorb perturbations and maintaining the same structures and functions. It also describes to which degree the system is able to self-organize, learn and adapt.

The first step of the research was to look, how these concepts were used and assessed in the scientific literature. The results were surprising: engineering resilience was by far the most used concept even if with the global change the return to pre-disturbance state might be impossible. The second most used concept was ecological resilience and the third one was social-ecological resilience. In other words, the more complex the definition of the resilience was, the less it was used. Further research on the indicators used to assess resilience revealed that engineering and ecological resilience apply very much the same indicators where as social-ecological resilience has a distinctively different set of them. The possible explanation for this difference is that engineering and ecological resilience consider resilience as system property whereas social-ecological resilience is more of a strategy to manage ecosystems for the uncertain present and future.

Finding the “right” concept
Which one of the concepts is the correct one then? Well, it all depends on the forest, the disturbance and the time horizon. The results showed that the three concepts are not contradictory but rather they can be looked at as nested hierarchy where engineering resilience fits inside ecological resilience which in turn fits inside social-ecological resilience. Depending on the situation, each concept can be as good as the others.

But how to choose the correct one for a specific situation then? The first step is to define the system: is it the resilience of a particular tree species or the value chain of the regional forest industry? This helps to identify, how complex a system is. For a simple system, a simpler resilience definition could be enough. The second step is to identify what are the disturbances and stressors affecting the system. Is it a single event that has a clear beginning and an end (e.g. storm) or is there a constant pressure (e.g. climate change)? This is essential, because engineering resilience requires that the system returns to the pre-disturbance state. If the disturbance does not end or the pre-disturbance state is impossible to come back, engineering resilience cannot be used. Furthermore, it is important to identify if the disturbance affects or changes the forest management requirements or other societal parts of forestry. If this is the case, it would be necessary to use social-ecological resilience because this concept is more equipped to handle these changes than ecological resilience. The third step is to identify the inspected time period. Engineering resilience can be applied in short, few-years-time periods. However, for longer time periods it is better to use ecological and social-ecological resilience, as the environmental and societal conditions are likely to change.

Resilience as a term is expected to increase in popularity even further. However, it should be always clarified, what exactly is meant with resilience. Especially because it is very difficult to implement the concept in practical forest management when there is conceptual ambiguity. And in times when we need more resilient forests than ever this will not do.

Nikinmaa, L., Lindner, M., Cantarello, E. et al. Reviewing the Use of Resilience Concepts in Forest Sciences. Current Forestry Reports (2020). https://doi-org.kuleuven.ezproxy.kuleuven.be/10.1007/s40725-020-00110-x