Fire damage to Doug Fir

Asked August 21, 2018, 7:12 PM EDT

Two 100-foot Doug Firs in my back yard were recently (2 weeks ago) damaged by a neighbor's garage fire. Flames shot up the entire height of the trees before firefighters were able to put out the blaze. The branches on that side of the trees were scorched and have been dropping needles every since. Who can I consult with an expertise in Doug Fir fire damage to determine if the trees will survive and are stable?

Multnomah County Oregon

4 Responses

I suggest you start by looking closely at the tree and making your own assessment of the tree condition based on items discussed below. And you can send me photographs showing the size of the tree and the degree of scortch on bark and foliage.

A key question is whether the fire burned around the base of the tree and how much heat it was exposed to at the ground and on the trunk - was it enough to damage the cambium under the bark? Large trees with thick bark have greater insulation and suffer less heat damage.

In terms of branch and foliar damage, did the leaves and twigs actually burn, or were they just damaged by heat from an adjacent flame?

If all the damage was on one side and at least 50% of the tree crown appears undamaged, it may have a chance.

The real test is the test of time - wait and see where the tree has live buds that green up next spring and in the 2nd year. And watch for signs of poor vigor and crown dieback during the growing season over the next year or two.

Also, though the tree may appear healthy next year, you also need to watch for insects attacking fire damaged trees.

Here are some references to help you:

Thanks. The was no damage to the base of the tree, as the fire got into the tree via branches about 10 feet up. So, the trunk is in good shape. If it helps, I have attached two pictures. One is from my street/yard looking to the north; the damage doesn't look too bad; lots of green needles, etc. However, the second picture is looking south from my neighbor's street/yard where the fire started and where the flame shot up the trees to the top. You can see the damage there is rather extensive. Any reaction to the pictures? I'm OK giving it the test of time so long as there is little risk of the tree(s) falling and causing damage to people or houses. I also would be glad to hire a doug fir expert to do an inspection if I knew who to contact. Any thoughts there? Thanks.

P.S. I saw my question and your answer in the Oregonian yesterday.

Based on your photos, it looks like there is a good chance for your trees to survive. The full, healthy crowns on one side are a good sign. The tree on the left (from the burned side view) appears to be worse off and less healthy in general compared to the tree on the right. I do think the "wait and see" approach is OK at this point. See how the trees recovers next spring. And again, please refer to the guidelines in the articles I sent earlier.

With regard to hazards of falling branches, even if some branches are dead, it will take a while for them to weaken enough to fall. Finer branches and twigs will start falling sooner. For a formal hazard tree evaluation, you would need to hire an arborist.

Thank you, Glenn. This is very helpful. I appreciate it.