Live Oak with Root Issues

[ron in sc]

Location: Charleston, SC

Tree type: Live Oak

Problem: Was surrounded by railroad ties, estimate them to have been 6' to 8' long and surrounded on all four sides to a height of maybe 16" to 18", also had hydrangeas in the box too.

The tree was pruned professionally and I was advised that dirt to high around trunk of tree and that tree should not have essentially been boxed in like it was. Tree has been like that for 25 years and it has not grown real well like other live oaks on my property.

I removed hydrangeas and everything else very carefully, use my pressure washer to do the last bit on relatively low pressure and found what is I think is the root flare, please see photos below. Part of the flare which I could only find on one side of the tree looks kind of like cypress knees. I did get it down to what is essentially ground level. It looks a little ruff in the photos but its not that bad as far as damage goes. I do intend to have it professionally fertilized.


Question: Should I put back any dirt, dig deeper or just cover what I have exposed with mulch, oak chips? Or do something else?

 

[Kneejerk Bombas]

You don't want to put the dirt back, and it would be hard to remove any more, so At this point I would cover the mess with a thin layer of wood chips, mostly as a cosmetic treatment but also to prevent the exposed root from drying.
The suggestion about fertilizer scares me a bit. Unless there are specific soil deficiencies, adding unneeded fertilizer only stresses the tree more.
There is a chemical called Cambistat that has been used with some success for trees with root damage. You might want to look into that.
Be aware that uncovering buried roots is a tricky repair and nothing is written in stone, use your best judgement and expect any results to be very slow in showing.
I'd like to see some pictures of the crown.

 

[treeseer]

Question: Should I put back any dirt, dig deeper or just cover what I have exposed with mulch, oak chips? Or do something else?

Yes. please, put some soil back immediately; you've exposed a lot of roots that are dying while they're drying. Some big ones also look to be scraped up pretty bad; you may have done some harm along with the good. Profewssionals like Mike would have used a pneumatic tool.

The third image shows a deep cavity which should be cleaned out and measured to get some idea of the tree's stability. You'll have to dig deeper at its opening. This should be done more carefully than the soil removal was--do NOT break any more barriers!. Roots growing across the trunk near this cavity are girdling and should be pruned; smaller ones now, bigger ones MAYBE in the fall.

For more on root pruning, see Detective Dendro in the April issue of Arborist News. Coming to your mailbox soon if you're in ISA. If you're not, why not?

We all trust that your pressure washer did not have any bleach in the tank.

Hydrangeas may have stayed, imo--disturbing oak roots during removal (esp. this time of yr) again may have done more harm than good. Getting the RR ties away was a good thing, IF you cover the exposed roots immediately with good soil.

Test the soil (SC does this for free) outside the box before fertilizing--Mike was right about this; even a broken clock is right twice a day.
Dosing a decaying tree with excess nitrogen feeds woodrotting fungus.

Yes please send pictures of the crown, and the inside of the cavity when you get there.