Rail fence consisting of a zigzag of interlocking rails WordNet 3.0 & Open English WordNet

A split-rail fence, log fence, or buck-and-rail fence is a type of fence constructed in the United States and Canada, and is made out of timber logs, usually split lengthwise into rails and typically used for agricultural or decorative fencing. Wikipedia

A zigzag fence built from interlocking split logs or young trees, not secured with nails. Wiktionary

A zigzag fence composed of rails crossing one another at their ends. Wiktionary