OK, folks -- I'm having the most difficult time posting on here, and I'm not new to this! Ugh,...OK, this is a test post.

To continue:

I noticed this on our branches in 2014:

Some experts said it was the same fungus/canker, but others said it looked like animal/deer damage. We do have a ton of squirrels, constantly gnawing on our tree bark.

Since 2011, though, we have noticed the trees aren't nearly as robust and healthy as before. Some of the branches do just seem to suddenly die in the middle of springtime, right as they're leafing out. This week, I noticed quite a number of leaves with brown margins:

Most of the branches have these dark areas which appear to be where squirrels have gnawed all the way around, and the bark is healing (I think):

Every year since 2011, I wonder if that's the year we really should take the trees down (before they get even larger). But they always seem to come back okay at the beginning of springtime. Are these signs of declining trees? TIA.

The trees are planted in our lawn, evenly/well watered, mulched:

Thanks so much, bostedo. We're actually in eastern Fort Bend county, so I'll check in with them and have an arborist come out.

Checking back in! Over the course of the months, the condition of both trees continued to decline: every time new leaves were put out, they all started to brown at the edges. (We planted another oak at the same time in the front yard, and that tree is 100% fine.) We made the decision to take them down, sadly.

DH took the left one down to almost soil level about a month ago. I immediately 'treated' the bark/outer ring portion with Roundup. On a different day, he took the right tree down to about 3'. No Roundup applied to that one yet.

How best to remove as much of the left stump as possible, so the grass can grow in? And if it wasn't a good idea to take the stump that low, we still have the opportunity to take a different approach with tree #2 (right).

Thanks for any advice.

I know Shumard oak is often recommended for zones 8 and 9, but from my experience they seem to be a bit finicky. I have several that are about a decade old, and none of them really look "good" in my opinion. In fact, two of them had a stem canker which made the top break off and the trees had to grow a new leader. The literature says they are native to the gulf coast region, but I can tell you I have walked through many forests here and I have never seen a naturally occurring Shumard.

Water oak, Laurel oak, and Willow oak all grow like weeds here, but unfortunately they don't have that pretty leaf shape or fall color. Swamp Chestnut oak is probably my favorite oak for my area, and they're not that common either.

Thanks for sharing, alabama. Coincidentally, the current (remaining) Shumard in the front yard actually replaced a Water oak that struggled for about three years. Some folks in the neighborhood (this was early on in a young subdivision) had Waters in their front yards, and I loved the leaf shape. And I presumed (wrongly, as it turns out) that if the builder was approved (by the local homeowner's association) to plant this variety, surely it was recommended for our area.

It really saddened me to take down the two Shumards in the backyard, but I knew it would be much more difficult with each passing year. In hindsight, we probably should have paid attention to the signs a few years ago and just taken them down then. It certainly would have been a lot less work.

You don't put down weed & feed in the spring by chance do you? I know atrazine can damage trees over time.

The big black area in the first pic looks like Hypoxylon canker, probably just a result of stress that already existed.

http://www.arborilogical.com/tree-articles/hypoxylon-canker/

No weed & feed for us, partly for the reason you mentioned.

One of the 'tree guys' from a local county extension mentioned hypoxylon canker when the trees first showed signs of that burnt/sappy bark look. However, I never noticed the trees go through the asexual (dry & dusty spores) phase, and the trees hadn't experienced any environmental stresses that might make oaks more susceptible to HC. Most of the limbs on both trees died well before winter. DH and I decided to take the trees down the following spring; but to our surprise, new branches sprouted and the trees came back. But that's when the sickly leaves started.