Shade trees, old posts and shared fence lines
Large trees are a mixed blessing for a fence. Roots can lift or crowd a post, branches drop onto rails after a storm, and shade keeps wood damp so lower boards rot sooner. Where a fence runs through or beside a mature tree, the layout often has to bend around it instead of cutting straight through the roots.
Older yards also tend to have shared fences, patched by two or three owners over the years. Before tearing anything out, it helps to talk with the neighbor, because the fence may belong to one side, both or neither. A short, friendly conversation avoids a lot of trouble later.

