Those limbs are huge. Are they supported in any way?

I can not say for the tree posted by bengz6westmd, but with the tree on St Simmons and many of of slightly smaller size in the area , the limbs are not support by artificial means.

Astounding!

Thanks beng and KR.

L Clark, looking closely at the 1st pic, I can't see any supports. Those huge horizontal branches require very strong wood to keep off the ground.

Judging by the white picket fence in the background and wooden benches surrounding the trees interior, I think this is the same tree:

https://www.colonialwilliamsburg.org/trend-tradition-magazine/trend-tradition-spring-2019/tall-treasure/

Not as old as one would've thought.

I think the Compton is semi-evergreen at best, right? Maybe tardily deciduous?

Dave, I would think semi-evergreen is the case, seeing the live oak parent. Perhaps keeping it's discoloring leaves all winter and then dropping them w/the new leaves.

The International Oak Society has this great article on Compton Oak: Hybrid Highlight: Quercus xcomptoniae Sarg.

The article notes that, "Compton oaks from different sources planted in mid-Missouri (USDA Zone 6a) are proving to be perfectly hardy and have adapted to different soil conditions. They are typically semi-evergreen, holding green foliage until January or February"

Regarding hardiness, the article also notes that, "At Starhill [Forest Arboretum] (USDA Zone 5b), the trees appear to be at their hardiness limit: one of three trees from different wild sources has died, and while the other two survive, they do not appear to be happy in that climate"