Author Archives: ahrensg

Considering Assisted Migration for Trees in a Changing Climate

Posted on by

Trees are genetically adapted to their local climate. Local populations of trees may become maladapted if climate changes faster than species or populations ability to move or evolve. Recent research on the genetics of Douglas-fir stated that “Current populations are expected to be poorly adapted to future climates.”1 The authors also suggested “Human intervention will be required to ensure productive and adapted Douglas-fir forests in the face of climate change.” An approach to addressing this problem is assisted migration – the deliberate movement and establishment of a new population of a species or genetic type outside its current geographic range to another in order to introduce better adaptive traits.

What types of trees would you plant if you wanted to anticipate a warmer climate in the future? How would you decide? Continue reading →

Managing Forest Health and Resilience to Climate Stress

Posted on by

By Glenn Ahrens, OSU Forestry and Natural Resources Extension Agent – Clackamas, Marion, & Hood River Counties

Dying Douglas-fir trees have been a common sight in western Oregon in recent years due to drought-related problems, exacerbated by diseases and insects that attack stressed trees. History shows that periodic drought is to be expected in western Oregon and Douglas-fir forests are adapted to summer heat and drought to some extent. But extreme drought causes tree morality and raises concerns. In the news about climate change, there is a lot of talk about higher levels of heat and drought being the “new normal”. Is the recent drought “normal” or “abnormal” for western Oregon?  Either way, how can we manage our forests to improve their resilience – their ability to withstand climatic extremes? Continue reading →

Seeking Practical Knowledge of Climate in Oregon

Posted on by

By Glenn Ahrens, OSU Forestry and Natural Resources Extension Agent – Clackamas, Marion, & Hood River Counties

As a forester, I need a basic understanding of local climate to guide site-specific decisions –decisions like what species to grow and how many trees per acre to plant. With all the ongoing studies of climate change, I have been looking for practical information relevant to climate and trends affecting forests in Oregon. At an Extension Forestry conference in 2006 in Fairbanks, Alaska, I learned that increased temperatures over recent decades in Alaska had noticeably extended the growing season, melted permafrost, and exacerbated recent forest fires. This stimulated me to learn more about climate science related to my location in Oregon, where I had not really noticed any warming trends amidst the year to year variation in the weather.

How has the climate changed in Oregon? What are anticipated future changes? How might this affect forest management decisions? Continue reading →