Tree Poisoning

Asked May 8, 2019, 1:50 PM EDT

I have two very large Cedar trees100'+ on my property that are dying. In our general area there are lots of other cedars that are looking perfectly healthy. I am concerned that a neighbor who lives above me may have poisoned the trees because when they asked if they could top the trees to improve their view of Mt. Hood my wife and I told them that we would rather not have our trees topped. It just seems more than a coincidence that in the area those are the only two cedars that are dying. Is there any testing that I can do on the bark, soil or foliage that would show if any chemical had been poured around the trees that could be poisoning them. Thank you

Clackamas County Oregon

5 Responses

Careful diagnosis will be very important before making any conclusions or accusations in this kind of situation. First, it is not uncommon to have a couple of trees die in an area surrounded by healthy trees. Much depends on the species of cedar you have. So you should start by getting a definitive identification of the tree species. And then proceed to investigate possible causes of death for that species in your soil and site environment.

Examination of the tree and even testing of its parts for evidence of poison may be possible if we eliminate other common explanations such as disease, insects, soil drainage, soil compaction, etc. But even if one found a poison, it would be difficult to prove who did it.

Can you send photos of the tree and its parts to help with identification? At a distance to show whole tree, bark and branch structure, and close up of foliage, branches and bark.

Attached are photos. I am sending two separate responses so I can send 6 photos.
Thank you.

Here is the 2nd email with 3 more photos. Please let me know if there is any other info I can provide.
Thank you very much for your help and quick response.
Terry Reede 503 407-2100

Just wondering if you got my two emails with attached photos? We are trying to get a lot of water to the root system due to the hot weather that has hit so quickly. Also we have put down a layer of much. On Monday we will be getting load of aged horse manure which we plan to put down around the base of the two trees and plan to continue giving lots of water. We are so hoping we can save these two majestic trees.
Thanks for any feedback.

From your photos, it appears that these are western redcedar. Unfortunately, the tree that is looking brown is dying and unlikely to recover. There has been an increasing incidence of large western redcedar dying rather quickly in many locations around the Willamette Valley and foothills as well as up in SW Washington. We have been investigating, but there is no clear explanation. No pathogens or tree killing insects have been confirmed. A big factor is likely to be climate stress due to excessive heat and drought, repeatedly since 2015. Watering and mulching is a good idea, but the watering should be deep, every two to three weeks, rather than more frequent shallow watering.