Silviculture and Climate Change

Written by Ronald Mahoney

Silviculture deals with management decisions in ecosystems dominated by trees. But other organisms and ecosystem components besides trees are affected by climate change. Trees are the most visible barometer of change, and because they are usually the dominant organisms in forests, changes in trees have many ecological as well as economic consequences. Most temporary changes as well as long-term changes are beneficial to some organisms and detrimental to others.

Silviculturists, other natural resource professionals, and landowners need to think through the entire site and data they have gathered as part of developing a current status report and a plan (prescription) to guide future actions. All of the professionals and decision makers need to consider how the vegetation, precipitation, and risk factors such as fire may interact with climate change. In the future, more exact data and scientific insights will provide more specific guidelines; still, current managers and owners need to make some decisions now.

The “art” component of silviculture is important because many of the potential adaptations and ecological aspects and relationships between species of trees, other plants, and many animals have not been adequately studied and defined. There are many tolerances in plants and other organisms that have not been tested in current environments, and a few surprises may be in store for the future. Seed transfer zones will need to be researched and redefined. Equally important, there needs to be emphasis on thresholds of response.

Most landowner objectives do not include surprises, and climate change poses a real challenge for silvicultural prescriptions that either avoid or accommodate the unexpected, especially given the long life of trees and even greater longevity of managed ecosystems.

To incorporate climate change in silvicultural prescriptions, research must be broadened and intensified. Recent impacts to subalpine fir, western larch, aspen, and Alaskan yellow-cedar provide some current insights into how measurable climatic changes that have occurred over the past few decades have driven measurable changes in tree species growth and mortality.

Resources available:

• Silvics Tools for Land Managers
• Using Adaptive Forest Management to Address Uncertainty
• Experimenting with Non-Native Trees
• Forest Understory
• Mitigating Forest Disturbance
• Climate Change and Planting Trees
• Linking Silviculture with Identified Vulnerabilities
• Evaluating and Prioritizing Which Silvicultural Options are Best