"It’s not so simple, especially when some deed descriptions reference landmarks that may no longer be there such as trees or canebrakes or streams that may have altered their course." Typically, in Alabama, rural land surveying and mapping relies on the Township and range system, and there are indeed monuments and benchmarks at defined location at least every square mile or so. A survey ties into those known points. I have looked at GA and TN surveys that reference "the well where Mr. Jones' cow fell in,.... to the big lighning struck oak, of in the bend of the branch", but that is awfully rare here. We do have to deal with changes in water courses over time.
Thats because Tennesee and Gerogia are both Metes and Bounds states. Alabama is based off the PLSS system.