Many native forest trees are getting stressed and dying all around us. In more than fifty years of working with trees, I have never seen anything like this. What is going on?
The reason numerous native Douglas-firs, western redcedars, true firs, cottonwoods and other trees are looking so sickly and some are dying has to do with water—or the lack thereof. None of us can live very long without water, and we need a regular supply of it to survive. Without that…well, you know what happens. Trees are no different.
Yes, the reason many trees in our region are dying is because they are thirsty. As of the date of this blog post, all of the Willamette Valley in western Oregon is either in a moderate or severe drought (https://www.drought.gov/drought/regions and https://droughtmonitor.unl.edu/CurrentMap/StateDroughtMonitor.aspx?West).
“Drought is a period with reduced precipitation and above average temperatures. Across all Oregon counties, 2013-2015 proved to be record drought years. Although these may be peaks in a drought cycle, trends show increasing average temperatures and decreasing average precipitation. In addition, winter snowpack has been disappearing earlier in the year and the duration of summer weather has been extended” according to the Oregon Department of Forestry’s article entitled “Drought Stress in Conifers” published in February 2019 (https://www.oregon.gov/ODF/Documents/ForestBenefits/Drought.pdf). The same article goes on to say that…
Drought conditions create water stress inside the tree and can reduce growth or cause mortality. Tree water stress is an internal shortage of water that occurs whenever water loss exceeds uptake long enough to cause plant damage or disturb physiological processes.
Drought damage in trees is due to one or all of the following factors: