Cremains memorial tree- locations?

Hello, when my brother passed away we opted for a memorial tree urn, that has grown to plantable size over the past year. The problem is, we aren’t sure where to plant it. On any of our private property doesn’t feel like the best space as over time we all might move. We do have an option to plant on family land, but it’s a few hours away - and at some point that might also transfer ownership prohibiting visitors. His children are just under 20 - we want to ensure that if they choose they will have ability to visit for at least their lifetime.

He loved nature, hiking, exploring and his very existence was free spirited. So a park would be the perfect choice, but they typically require you to pick their species of tree - we have a blue pine species (I think Colorado- his aunt made sure it was a plant that could grow in our zone and not invasive) but, that isn’t on any of the lists. I’m starting to think divided ashes or ash spreading somewhere might’ve been the better choice.

Does anyone know a public park / woods space where we could plant without immediate risk of it being removed during clean up? It’s not a problem to pay, but I hesitate to do the 5 year adoption strategy that’s some of the parks have because eventually there might not be someone to keep up with the fees.