When we redesigned our back yard, we decided to let some volunteer native oaks live. Some that were too much in conflict with the design were removed, but in other cases the design was modified to allow the trees to remain. Since we stopped mowing a patch of weeds in the front yard, another oak has appeared where it is much needed to shade the driveway.
This was probably an oak woodland before human development almost completely eradicated the ecosystem. Luckily, what’s left of the ecosystem is still attempting to heal itself, in the form of scrub jays finding acorns and burying them for later use. Since the jays don’t remember where they planted the acorns, it amounts to a natural oak revegetation project.
These trees should have incredible tap roots since they were seeded in place and their roots never started turning around as they would in a pot. Also, they’re from the local genetic population, so you can’t get any more native than that.
If you want to re-establish oaks in a more controlled manner, you can collect acorns in the Fall and plant them where you want trees to grow. Be careful that they haven’t been eaten by something – check for holes in the shells. If there’s a hole, odds are your acorn isn’t viable.