The leaning makes me think maybe it is root-bound from having been left too long in a pot years before having been planted where it is now. This is a very common occurrence that seems therefore likely to be involved when an established tree develops such problems. If it were mine I would carefully dig down a bit to look and see if there is a girdling root below the rotting area.

In what is perhaps a similar situation friends had a long established snake-bark maple pinch itself off on one side after many years in place. The section of trunk directly above the clearly visible, above ground constricting root (it looked like a boa or python wrapped around prey) turned black and oozing once things got to that point.

And the tree's crown began to decline - so they cut it down. This was too bad as it was a somewhat unusual tree right off the corner of their wrapping deck.

Ok, thanks. I'll dig a bit more downward. Generally speaking, are there any treatments that should be applied to the rotting area?

Need to find out what specific problem is first.

Mechanical damage or planted too deep.

If it got dinged when the sod was removed then that would explain the wounding. If there's no moist softness then it's not decay.

not much impressed with leaf discoloration in mid september ...

i do not treat bark issues ... fall is a great time for molds and mildew ... as well as fungus .... [im sure you are sprinkling the new sod.. perhaps it is related to that ... especially if you do it in the evening ....]

all that said.. the lean bothers me completely ... i would remove the tree ....

how far is the power line from the canopy ... ken

All of my pecan trees look a bit ragged by mid Seprtember, including the ones that are almost 90 years old. As for the lean, it looks to me like there's a larger tree to the right, and this one is simply growing away from it trying to get more light.

I honestly can't tell much about the trunk just by looking at the pics, but it just looks like some kind of mold to me. Does the bark feel loose it you gently pull it?

If we are talking about the white area then that does look fungal. If the tree doesn't go on to deteriorate beneath this presumed patch of growth - a closer view would be preferable - then there is apparently no problem. No problem due to the "mold" anyway.

The lean seems a bit much for it to have been induced by the larger tree to the right, which isn't even overhanging the pecan.

Unless the larger tree was cut back, away from the pecan recently.

Could have been leaned over by wind when it was younger. I have wild ones in the woods all sorts of shapes.

I believe this one was blown over by hurricane Erin back in 1995, but it's still growing today...