Knowledgebase
Why are my Douglas Fir tree tops dieing? #892512
Asked February 10, 2025, 2:10 PM EST
9 (out of 48) Doug Fir trees on my property have dead tops. I thought maybe gray squirrels were eating the bark (I can see missing bark), but a friend suggested that the trees were stressed because many of the trees are loaded with fir cones at the tops. These trees are approximately 30 years old and have always been healthy. The dead tops came on rather suddenly, a year or two ago. I assume the trees with the dead tops will eventually die?
I live in 2.5 acres. My neighbor logged his property a few years ago. I was also curious if this changed the water table enough to cause drought?
If anyone has some ideas, I would appreciate it.
Benton County Oregon
Expert Response
Hello,
Dead tops are usually a sign of extreme heat and drought stress. We are starting to see this in Douglas-firs in the Willamette Valley and Valley margins due to an increase in frequency and severity of heat combined with drought. Dead tops usually mean some root death has occurred, but whether or not it's severe enough to kill the tree is unknown without seeing the trees in questions. The good news is that they sometimes bounce back.
Logging would not change the water table. However, it may cause stress on trees which were previously surrounded by other trees and are now in full sun. This can lead to bark scorching and increased water stress.
This article outlines the decline of Douglas-fir in Southwest Oregon, though we are starting to see it farther north now too: https://extension.oregonstate.edu/catalog/pub/em-9406-trees-edge
