The fence and shed provides for a good scaling factor. I would say closer to 25’
Yep, you could easily place a tree stand anywhere in this area. Even if the bottom of the stand is at 30’ then, assuming you are 5’8” that puts your working height at 35’. Put a 10’ 1 ¼” PVC pipe at that height and you are at 45’ with much less leaves. A 20’ fence pipe might even put you above the tree. Now you are in lightning strike territory.
Above all, be safe, that is a long way to the bottom.