Climate change threatens forestland throughout Montana

This column is part of a series by the Kootenai Climate Group designed to inform our community about the current and projected impacts of a changing climate. Human-caused carbon dioxide levels continue to increase, causing average daily temperatures to rise. Here, we focus on what that means for forestlands, which are so important to the people of Lincoln County.

According to the 2017 Montana Climate Assessment, climate change will alter what our forests look like and even where they can grow. By examining tree growth rings, glacial ice cores and marine sediments, scientists determined that our forests evolved under remarkably stable climate conditions.

However, over the last 150 years temperatures have warmed, slowly at first and now much more rapidly. These new climatic conditions are pushing our forests and our ability to manage them into new territory.

Key findings of the Montana Climate Assessment include: The number of days per year that exceed 90 degrees Fahrenheit is increasing. Higher summer temperatures and lower humidity stresses trees and other plants by increasing water loss via evaporation. Dry soil conditions during hot summers lead to increased tree mortality and reduced growth.

Montana’s average peak snowpack has been declining in recent decades. Warming temperatures, especially during springtime, are likely to continue, reducing our snowpack at middle and lower elevations and further increasing the risk of summer drought conditions.

Mild winters are becoming more common leading to conditions more favorable to bark beetle survival. Larger populations of bark beetles will increase the risk of extensive beetle outbreaks and large-scale tree mortality.

Forest fires likely will be more frequent and more severe because of the increased amount of dry fuels and hotter summer temperatures.

Some previously forested areas no longer have climate conditions that allow for tree regeneration following wildfires and are transitioning to permanent grass or shrub lands. Tree seedlings are very sensitive to hot dry weather and the survival rate of new seedlings after wildfires has declined.

Climate change is expected to significantly alter Montana’s forested landscapes. As humans continue contributing greenhouse gases to the atmosphere, the magnitude of the effects of climate change will increase proportionally. Our forests increasingly will be affected by drought, beetle outbreaks, regeneration failures and wildfires. Forest managers can best maintain sustainable forest conditions by understanding current trends and planning for the projected range of climate scenarios.

If we collectively act now, we may be able to avoid the worst possible outcomes.

Submitted by Russ Gautreaux, Nora Reckin, Gene Reckin, and Kris Newgard for the Kootenai Climate Group