Why not some tall warm weather grass like switch or tall blue stem or a combination of several tall grasses. Briars and other weed plants will soon fill any holes. This will provide cover as tall as 6 feet. Planting will done only once and they should provide cover the first year. If you ever change your mind, you won't have to hire a bulldozer to doze out trees or shrubs. Maintenance should be minimum as well. A burn once every 3 to 7 years.

The disadvadtage would be no tree stands.