Clearing brush and saplings in tight areas.

[RoyJackson]

I see the OP has a 60" cutter (a Land Pride)...and I'd guess even if the cutter could get in the area, the tractor might not.

I'm not too enthusiastic about that tree shear for the reasons already discussed, but DR does have a walkbehind cutter on their website too, IIRC. Might want to look over the DR website to see what else is available.
Another option is one of those circular saw blades that fit on a weed wacker.
I'm suggesting this is a clearing job that will require being on your feet.

 

[oj may]

The smaller DR string trimmers have an attachment called the beaver blade. It's a round chainsaw chain. I have the largest walk behind brush mower and it will mow down 1.5 inch saplings. But it leaves behind punji sticks.

 

[aczlan]

Get a 2 wheeled Gravely with the 30" bush hog. It will take out most anything you can push over. That is just asking to be slammed head first into a tree when you try to take out one that is just a little too big.
Also note that Sweetgum is classed as a hardwood, not a softwood like the pines that they were cutting.

Aaron Z