We planted a young Fraser fir last March. It has a lot of
new growth, but has developed some dead-looking tips here and there that
are a reddish rust color. I am wondering if we have a serious problem or
should I just remove the affected tips and not worry about it? I have
noticed a lot of trees this summer on my travels out through the
Cumberland-Enumclaw area that look a similar cinnamon color and are
totally dead!
The problem you describe could be the result of drought injury, or it
could be one of several rust and fungal diseases which affect fir trees.
Was the tree watered well after planting? Here is information
on drought injury from Oregon State University’s plant disease database. Excerpt:
Drought injury usually progresses from the top of the tree downward and
from the outside to the inside of the crown. Top dieback and branch death
may be common. Defoliation of the mid-crown or loss of needles at the
base and tip of shoots can also occur in Douglas-fir. Older needles
commonly turn yellow and are shed prematurely. Roots may be alive even
though the entire above-ground parts are dead. Winter injury, gopher and
root weevil problems can produce similar symptoms.
Your description also sounds like the symptoms of Phytophthora, a fungal
disease which is common in our area. Excerpt:
Phytophthora root rot is usually a problem only in areas with poor
drainage or where flooding occurs. The fungus attacks the roots, which
rot and die. The infection moves up into the crown, where the cambium
(soft inner bark) turns reddish-brown or caramel in color instead of the
normal white to greenish color. Older trees may develop cankers on the
trunk, which are a dark reddish-brown when cut. The cankers may be
accompanied by split bark and oozing pitch. Lower branches wilt, turn
dark red, and die back. Younger trees are often killed outright, while
infected mature trees may show wilting, branch dieback, and/or gradual
decline.
Missouri Botanical Garden’s Integrated Pest Management site has information and includes an image of Fraser fir suffering from Phytophthora.
The Pacific Northwest Pest Management handbooks have a section on diagnosing and controlling phytophthora diseases.
I recommend taking a sample of one of the cinnamon-colored branches to a
Master Gardener Clinic, and also taking photos of the whole tree, so that
you can have the problem diagnosed. If you are near Enumclaw, the Pierce County Master Gardeners offer diagnostic clinics.