Cedar elm tree fungal infection?

Question: I lost a large cedar elm tree (approximately 26 inch diameter trunk) in the recent storm. The entire canopy came down and it was apparent that there was dead/diseased wood at the point where the trunk started to divide into major limbs. The last cut at the base shows a deep rust colored area, and I am wondering if it needs to be treated (or completely removed) to avoid affecting the tree with which it shared a  base. I assume they grew together over time. See photos.

responder: Travis County Master Gardeners  Replied May 12, 2023, 8:40 PM EDT
response: It is difficult to determine from your photos what the rust area in the inside of your felled tree is, but it looks very much like a fungal infection. I wonder if it is hard or has it started to become soft and mushy? Does it have any sort of odor? Either way, it seems probably that it is a fungal infection and could have been the reason why the tree collapsed so dramatically during the ice storm.  I certainly recommend removing the stump, or at least cutting it back as far as you can and hopefully below where the fungus is appearing. You will need to take care not to damage the tree's root system too much, since both trees are sharing the same roots. You many also want to treat the roots to a good dose of fungicide or neeman oil to try and control the infection so that it does not spread to the other tree. Unfortunately, at this stage there is no guarantee that the other trunk has not been infected. Watch this apparently healthy tree carefully over the coming months to see if there are other signs of infection, such as fungi (mushrooms) growing out of the bark.  Good luck - and hope your other tree is OK  Liz S.

responder: The Question Asker Replied May 13, 2023, 1:48 PM EDT
response: Thank you very much for your prompt response.  In answer to your questions, the discolored area is quite hard.  I used a hammer and wood chisel (very tangential angle) and there was no difference between the discolored and non-colored wood with respect to hardness..  There is no obvious odor until I got quite close and it smelled somewhat smoky rather than anything rotten.  There was no similar odor over the non-discolored wood.I plan to contact a "tree surgeon" to cut the stump down closer to the ground and will hope that this will remove most of the disease.  Do you have a short list of recommended tree specialists in the Austin area? Again, thank you for your advice!Susan A. On Fri, May 12, 2023 at 7:40 PM Ask Extension <<personal data hidden>> wrote:

responder: Travis County Master Gardeners  Replied May 13, 2023, 6:52 PM EDT
response: It is good news that the discoloration does not seem to be rotting the trunk, but I think you are wise to get in a stump remover and arborist.   We are not permitted to recommend arborists, but as long as you use one who is certified and knows something about Cedar El, you should be OK.   Liz S.       Travis County Master Gardeners   Buy our Award-Winning Publications! "Garden Guide for Austin and Vicinity": https://www.tcmastergardeners.org/garden-guide/ "From Drought to Deluge: The Resilient Central Texas Garden" https://www.tcmastergardeners.org/drought-guide/    For live support, call our help desk at <personal data hidden> (leave a message)            From: ask=<personal data hidden> <ask=<personal data hidden>> on behalf of Ask Extension <<personal data hidden>> Sent: Saturday, May 13, 2023 12:48 PM To: Travis County Master Gardener <<personal data hidden>> Subject: New response added to your question (#0099633)