Browning cedar tree

Asked August 16, 2019, 2:28 PM EDT

I have an established cedar tree in my urban front yard in Corvallis that has been shedding for the past few years and is now browning up the tree. This year I watered it more, but it continues to brown. I don't see other signs of bug infestation, but may be missing something. What can I try to save the tree? Where can I get consultation on it?

Benton County Oregon trees and shrubs

3 Responses

Thanks for your inquiry, can you please share a little more information so we can best assist you?

This includes bringing a sample of the plant with which you have a question or concern into the Extension office. Please try to include both healthy and affected foliage, and include some cones or seeds so we can properly identify what species you have, since this may help explain the issue. You can find us here: https://extension.oregonstate.edu/mg/linn-benton/have-gardening-question

If it is not practical for you to bring a sample into the office, please provide a photograph that captures the plant or section of your yard with which you have a question or concern. A wide-angle photograph and a close-up are helpful, in many instances. You can post it in a reply here, or email it our office via contact info listed in the link above.

We look forward to getting more information and working to diagnose the issue.

Your tree appears to be an incense cedar. Environmental stress such as wind, flooding or drought weakens trees to such an extent that they can no longer fight off insect infestations. Other stressors include cutting the trunk with a lawn mower or running into it with a vehicle. Regularly over-watering or extensive flooding fills the air pockets in the surrounding soil, robbing the tree of oxygen. Incense cedars (Calocedrus decurrens) weakened in any of these ways become susceptible to insect damage from flat headed woodborers (Buprestids) and cedar bark beetles (Phleosinus spp.). Do you see signs of insect damage such as sawdust or borer holes in the trunk?

Tree damage is usually due to a combination of factors. Multiple actions or changes may be needed to relieve stress and increase tree vigor. Possible strategies include:

  • Prevent soil compaction caused by vehicle or animal traffic near trees. Compaction can damage surface soils and roots, especially in clay soils.
  • Avoid direct damage to trees and roots by animals or machinery.
  • Reduce competing vegetation.
  • Irrigate landscape trees during dry spells. Apply water slowly over many hours, avoid frequent shallow watering. Apply mulch to maintain soil moisture.
  • Do not alter drainage near established trees (ditches, ponds, fill or removal of soil)
  • If insects or branch/stem cankers are evident, prune and destroy affected branches to reduce spread.
  • Do not fertilize during drought conditions; fertilization can increase a tree’s water requirements.

Here is are a couple of publications that you may find useful:

http://blogs.oregonstate.edu/treetopics/2014/06/27/whats-causing-die-back-incense-cedar/

https://www.oregon.gov/ODF/Documents/ForestBenefits/TreeDeclinesRedcedar.pdf

Hope this helps!