Redwood tree with a dying top. Also thinning branches all over the tree. - Ask Extension
We live 30 min south of Portland Oregon. Our redwood tree had a dying top then got a new one a few years ago. Now the top is dying again but a larger ...
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Redwood tree with a dying top. Also thinning branches all over the tree. #610857
Asked January 19, 2020, 4:31 PM EST
We live 30 min south of Portland Oregon. Our redwood tree had a dying top then got a new one a few years ago. Now the top is dying again but a larger portion including some top branches. The whole tree has shown a significant thinning too. The tree is about 60’ tall now. Possibly 30+ years old. What can we do to help it. Should I clean tree debris from under it? Some moles were under it last year. Last summer I did an occasional extra water. Should we limb-up branches that touch the ground? We love this tree, please help.
Clackamas County Oregon
Expert Response
This is a common problem in our area. To answer your question, I will simply quote a previous answer by our Forest Health Specialist:
"This
is a common thing we see with Sequoia. It can be related to a number
of factors. There is the possibility it is caused by squirrel damage,
i.e. we often see squirrels debarking and girdling tops and branches.
If you can see with binoculars...try to see if there is any bark at the
base of the dead portions of the crown.
Another possible cause is
drought effect on the tops. During our summer droughts, the tops of
some trees can be killed due to water stress. If this is a possible
cause, we recommend a summer watering in August and sometimes also in
September around the tree that saturates the soil with a slow soak.
This only needs to be done once a month. Finally it is possible there is a canker fungus in the top, but if this was it, you should also see other branches in the crown showing death also.
In summary...first look to see if the stems have been debarked by squirrels. If not, it is likely a drought stress issue. In that case, it is likely the tree will eventually form a second leader that will take over the height growth. If we have severe drought in summer, it is good to deep water the tree in August and again in September if we don't get rain.
I hope this helps. It is not unusual to see this around the valley. I don't think it will spread. "
I looked with binoculars and I don't see debarking. I did water the last two Aug/Sept seasons. It has done this before but this time it seems more severe with more branches involved and the whole tree seems to be getting thinner. Any suggestions if it is the "Canker Fungus"? Also, should I clear away tree debris from around the bottom of the tree and expose the dirt? There are large branches now touching the ground that used to be suspended in the air. Should I limb up the ones touching the ground?
To determine if there is any canker fungus, the most common method is to inspect the affected part of the trunk or branches at the point of transition between live and dead/dying tissue. Of course that may require climbing or pruning very high up on the tree to reach affected parts. For more information about stem canker disease on redwood and giant Sequoia, see https://ufei.calpoly.edu/files/pubs/Redwoodcanker.pdf
If canker disease is present, pruning and disposing of affected branches is recommended in order to reduce disease inoculum. Pruning lower branches and maintaining more air space between and
around trees can be helpful in reducing foliage diseases by increasing
air movement. But care must be taken to prune safely and properly to avoid other problems.
Pruning lower branches and removing excess woody debris is often desirable to reduce fuels and fire hazards. But it is good to leave some leaf litter on the forest floor to provide mulch and organic matter and to avoid unnecessary disturbance of the surface soil/root environment.
