Sometimes it’s interesting to see the internet searches that bring people to this blog. The above question was one of them yesterday. It’s a pretty hard question to answer precisely – I’ve got a whole chapter in the book called “What is a Hedge” and I still don’t claim to have the definitive answer, but here are a few quick thoughts.
Firstly, a hedge is traditionally a row of trees or woody shrubs that have been interlinked so as to form a boundary or barrier.
However this can’t be a precise definition. A hedgerow that has become gappy can still be called a hedge. And if I plant a row of trees on a bank or field boundary with the intention of laying them into a hedge, you could still call the row of trees a hedge, even though they are not interlinked.
My general theory is that a hedge is always the result of human intervention in the landscape – hedges can be grown (or early hedges were left on the edge of assarts, clearings in the wildwood), and managed as barriers, boundaries, screens or ornaments. The only kinds of hedge that aren’t intentionally created are fencerows, meaning the lines of vegetation that grow alongside barriers such as walls and fences because they are protected from the elements. But these are still caused by the creation of the original barrier.
In all these cases the hedge exists because of human action. A line of trees is a hedge if it is functioning as a hedge, is intended to become a hedge, was once intended to be a hedge, or grew alongside something else that was intended to function as a barrier or screen.
So I’d suggest that a hedge is never an entirely natural element, and can always be explained in terms of its use or intended use as a barrier, boundary, ornament or screen.