The Society of American Foresters Dictionary of Forestry defines silviculture as “the art and science of controlling the establishment, growth, composition, health, and quality of forests and woodlands to meet the diverse needs and values of landowners and society on a sustainable basis.” Silvicultural treatments span a wide array of approaches, including (but not limited to) thinning, regeneration harvests, planting, site preparation, pruning, and prescribed burning. These approaches make up the toolbox that foresters utilize in managing for landowner and society’s values, such as wildlife habitat, timber, water resources, recreation, and carbon sequestration, among many others.
To develop the ASCC study, we brought together a core team of scientists and managers interested in integrating climate change adaptation into their silvicultural planning and on-the-ground management actions at each site. The big question ASCC is poised to answer is:
What actions can be taken to enhance the ability of a system to cope with change while continuing to meet management goals and objectives?
Touring the Southern New England Exurban Affiliate Oak project ASCC Site. Photo Credit: Amanda Bunce, University of Connecticut.
Silviculture and Climate Adaptation
Articulating a desired future condition (DFC) that aligns with management goals is a crucial step when developing silvicultural prescriptions. Inherent to developing DFCs is an understanding of how vegetation develops over time, including response to disturbances and silvicultural treatments. However, our understanding of the future impacts of a changing climate on forest development is limited. Climate change presents an ongoing challenge to management. To accommodate the uncertainty surrounding climate change impacts, silviculturists need to consider a range of potential futures in decision-making to best manage forest resources for future generations.
Adaptation actions are designed to specifically address climate change impacts and vulnerabilities to meet management goals and objectives. This might mean continuing management practices that are currently taking place, or it could involve trying something new and different to address climate change. The ASCC experiment is looking at a spectrum of adaptation options ranging from resistance to transition.
Conceptual diagram of the Resistance – Resilience – Transition (RRT) framework applied to the ASCC Network, positioned vertically along a spectrum of ecological persistence to change i.e., adaptation). The y-axis presents the degree of alignment with current conditions relative to the future range of acceptable outcomes (i.e., desired future conditions). Graphic by Kailey Marcinkowski, Northern Institute of Applied Climate Science.
Climate Change Adaptation Options
Which approach best prepares forest ecosystems for climate change? Adaptation options occupy a continuum of management goals related to their levels of desired change:
Resistance— actions that improve the defenses of the forest against anticipated change or directly defend the forest against disturbance to maintain relatively unchanged conditions
Resilience— actions that accommodate some degree of change, but encourage a return to a prior condition or desired reference conditions after disturbance
Transition— actions that intentionally accommodate change and enable ecosystems to adaptively respond to changing and new conditions
No Action Control— given that climate change impacts all forests globally, under the ‘no action’ forests are allowed to respond to climate change in the absence of direct silvicultural intervention as an appropriate baseline
The ASCC project explicitly tests these adaptation options, linking them to site-specific management objectives, desired future conditions, and silvicultural actions. Our working definitions below closely follow Millar et al. 2007. Conceptual diagram of the Resistance-Resilience-Transition (RRT) framework applied to the ASCC network (see Nagel et al., 2017 and Nagel et al. in press for more detail). Within panels, forest conditions are characterized by simplified forest diagrams that present (left) and idealized Desired Future Conditions (DFC; right) shaped by the adaptation trajectory due to forest management (solid purple, orange, and green lines) relative to the uncertain trajectory of climate change (black hashed line) and no action. To manage conditions in relation to climate change, the relative degree of forest management intervention is illustrated in terms of frequency (interval) and effort (length; vertical arrows). Within panels, the vertical axes refer to the degree of alignment with historical range of variability (HRV; Keane et al., 2009) or future range of variability (FRV; Seidl et al., 2016 ), along with a generalized distribution depicting the range of acceptable outcomes in terms of future conditions. RRT panels are positioned vertically along a spectrum of ecological persistence or change (i.e., adaptation). Note, all ASCC sites also contain a “no-action” control treatment not explicitly depicted in this conceptual diagram, although it is best captured by the line labeled uncertain climate change trajectory” (black hashed line).Graphic by Kailey Marcinkowski, Northern Institute of Applied Climate Science.
Resistance
Managing for resistance means improving the defenses of the forest against anticipated changes, or directly defending the forest against disturbance, in order to maintain relatively unchanged conditions. The resistance option typically involves investing resources into maintaining what is currently on the landscape. Over time, the effort and resources needed to maintain forests within developmental pathways that assume a static environment, will increase – meaning, this approach could become increasingly costly as climate changes into the future. The resistance option is best utilized as a short-term strategy or to maintain resources of high cultural, economic, or ecological value.
Conceptual diagram of the Resistance framework applied to the ASCC Network. Graphic by Kailey Marcinkowski, Northern Institute of Applied Climate Science.
Resilience
Managing for resilience means accommodating some degree of change, but encouraging a return to a prior condition or an identified benchmark condition following disturbance. Resilience treatments in forest ecosystems are aimed at coping with disturbance. A resilient ecosystem is often immediately impacted by low intensity disturbances, but can quickly recover to conditions resembling those pre-disturbance. In other words, resilient ecosystems are very elastic. In the ASCC study, resilience treatments are designed to enable forest stands to rebound from disturbances and tolerate a wider range of climate shifts. Similar to the resistance option, the effort and resources needed to maintain or improve resilience in forest ecosystems may become more difficult and require more investment over time.
Conceptual diagram of the Resilience framework applied to the ASCC Network. Graphic by Kailey Marcinkowski, Northern Institute of Applied Climate Science.
Transition
Finally, managing for transition (or response) means intentionally accommodating change and enabling ecosystems to adaptively respond to changing and new conditions. The transition adaptation option requires making an intentional, directed change to an ecosystem, which can include trying novel approaches in an effort to identify which ones best meet management objectives under future conditions. The transition option may require more effort upfront to begin moving a stand toward a future-oriented desired future condition that is defined within the context of projected future climate. Through this approach, ecosystem adaptive capacity will likely increase, and the effort needed to maintain that desired condition will potentially decrease over time. The end result will be a forest that may look different from current conditions but still provides critical ecosystem functions and services.
Conceptual diagram of the Transition framework applied to the ASCC Network. Graphic by Kailey Marcinkowski, Northern Institute of Applied Climate Science.
RElated Literature
Nagel, L. M., Palik, B. J., Battaglia, M. A., D’Amato, A. W., Guldin, J. M., Swanston, C. W., Janowiak, M. K., Powers, M. P., Joyce, L. A., Millar, C. I., Peterson, D. L., Ganio, L. M., Kirschbaum, C., & Roske, M. R. (2017). Adaptive Silviculture for Climate Change: A National Experiment in Manager-Scientist Partnerships to Apply an Adaptation Framework. Journal of Forestry, 115, 167–178. https://doi.org/10.5849/jof.16-039
Millar, C. I., Stephenson, N. L., & Stephens, S. L. (2007). Climate Change and Forests of the Future: Managing in the Face of Uncertainty. Ecological Applications, 17(8), 2145–2151. https://doi.org/10.1890/06-1715.1
Swanston, C. W., Janowiak, M. K., Brandt, L. A., Butler, P. R., Handler, S. D., Shannon, P. D., Lewis, A. D., Hall, K., Fahey, R. T., Scott, L., Kerber, A., Miesbauer, J. W., Darling, L., Parker, L., & Pierre, M. S. (2016). Forest Adaptation Resources: Climate change tools and approaches for land managers, 2nd edition. Gen. Tech. Rep. NRS-GTR-87-2. Newtown Square, PA: U.S. Department of Agriculture, Forest Service, Northern Research Station. 161 p. https://doi.org/10.2737/NRS-GTR-87-2
