Justinmc;
The main thing that jumps out at me are the YOUNG age of most of your trees. By that, you can rule out the Spanish and Ancients. That leaves possibly the KGC or a local group, OR a single individual setting up a vault of his own. That's why you must learn all you can about who owned the land and what was their economic situation. Concentrate on the last 200 years of history. Most of those small diameter trees in your photos are less than 50 years old, PLUS, those twisted up limbs could easily be from nature's storms reforming the trees' shapes.
Jmc, I am NOT trying to rain on your parade here. Just, asking you to use your common sense and look for any possible leads to valuables in your area without putting so much pressure on yourself in feeling you MUST succeed. Treasure hunting should be a more relaxed situation and not a high pressure JOB. And, lastly, be ready for disappointments as well as successes. "IF" is the biggest word in the English language............."IF" there is a treasure in the area; and "IF" you find a lead to it; "IF" you follow the "trail" of information faithfully; "IF" you finally find the spot where it's hidden (after maybe YEARS of search), THEN, you may find that someone has been there already and recovered whatever was there. This is why most professional treasure hunters research more than one lead at a time..........some, as many as 4, 5, and 6 at once. Treasure hunting has been romanticised , but it is actually a LOT of work with more than a little bit of disappointments. So, pull up your boots and get to researching. By the way, what lead you to discover that piece of metal your compass is resting on??