looks like physical damage of some sort - almost looks like sun scald you might see up north in the winter. The pic isn't great, but it looks like it is trying to scab over. If the tree wound scabs shut before the tree rots out, it should be fine. Keep in mind that there could be a weak spot left in the tree down the road.

Dang it... thought I was posting in the Florida forum... if you ARE up north, and the damage is facing southwest, it could BE sun scald. Mature trees usually grow out of that, but young thin bark is susceptible. You could wrap the thin bark in winter, or try a latex wash.

hi corkball, thanks for your comment. I am in Texas. this tree, plus another one which is 8 feet away, both have the same problem, and the wounds are on the southwest side indeed. would you suggest that I use tree wrap to wrap the wound now just to avoid losing more bark?

are they rather recent transplants ..

pull back the mulch.. and then the soil.. and find the root flare ... and lets find out if its planted too deep ...

https://duckduckgo.com/?t=ffnt&q=tree+root+flare&iax=images&ia=images

the tree is healing itself ... encapsulating is the term ... this tree requires nothing further from you in that regard ... no wrap.. no paint.. no goo..no nothing ... all you can do is screw it up ... so dont do that ...

sun scald is not unusual on transplants ... but it should not happen on well established trees ..

and this is what having buried tree trunk causes.. so go all ncis oon it .. and gently find out ... and report back ...

ken

oh,. i know what i forgot ...

the actual injury.. could have been very slight.. and many years ago ... and just showed up .. so its hard to say if anything is going on.. besides healing..

again.. injury in that spot is usually related to digging a tree from a tree farm.. and moving it thru to seller.. and then you ...

so.. again.. im back to.. how long have they been there???

ken

hi Ken, the trees were planted by the builder back in 2016, and i noticed the wounds since last autumn, and still look the same now. I will go check out the root flare. thanks!

Judging by the encapsulation that damage was done long before last autumn.

Base of stem definitely too deeply buried at this time. "This time" = maybe if the mulch is pulled back to where it should be anyway the soil level beneath will turn out to be OK.

don't wrap the tree in the warm season. Only in the winter. It limits the freeze/thaw cycle damage.

Trees are usually adapted to the cold in their area. My guess is in TX, it was that brutal Feb cold with bright sunshine that did it. Normal winters shouldn't affect your trees.

I have a pet theory about how heavy large transplants are and how thin their bark still is. To test it I may need to go wack a bunch of 10-15ft trees in the wild with a baseball bat and come back a few years later.

I agree with floral-uk, that damage is years old,likly from collisions with lawn maintainance equipment. Very commmon and very serious. A trained arborest can't fix the damage and nither can you,even with help from interweb. I would plant new tree(s) rather than wait for that one to wither away.

i see no reason to abandon ship on trees that are healing ...

Ken,opinions vary on how much damage justafy's replacement. That tree will never fully recover and will be a sitting duck for decease and high wind from now on. In Texas and other areas with punishing summer heat,trees are closer to neccety than amenity so gambling is ill advised. A conservity approach would be to PROPERLY plant and maticously maintain a healthy transplant (preferably in fall) then wait and see. My experience has been that a new trans plant has outgrown the injured origional within 5-6 years then leave's it in a cloud of dust in future years. Don't slap your trees with weed wackers,don't scrap them with mower decks and don't cover flares.

I find it hard to believe with that much mulch piled around that tree that the trunk ever saw a weed whacker or lawn mower close enough to do damage to the trunk.

The damage is consistent with trees that are planted too deep, having the root flare smothered. Or it might be a mulch volcano, which would produce the same results.

Chances are, if he has another tree with the same problem, then both were planted the with the same incorrect planting practices.

I didn't read this whole thread but has anyone asked the OA to sweep back the mulch and/or soil to find out where the root flare is? It certainly would be fun to find out.

This old house and root flare problems:

https://www.youtube.com/watch?v=fI12XNNqldA