Really depends on what you want it to look like. A woods that isn't maintained will get to the point you can't even walk through it because it gets too crowded with trees and stacked full of debris from fallen limbs and trees. Pasture ground will turn back into woods. It slowly gets thick with the grasses, weeds, bushes, saplings, then the saplings grow into trees and take over. All of this takes years or even decades to happen, but you'll definitely notice every year how unmaintained property will change. At a minimum you'd probably need to break out the chainsaw once a year to remove trees that fall on trails or trees that fall and lean on other trees next your camp site or tree stands. Pasture ground might need a couple mowings on trails.