Posted: 28/08/2015 at 12:12
Up to you of course, but if you prune severely you'll end up with loads of water shoots and a sort of untidy lollipop/pollard effect.
I took notice of the aboriculturist I employed because he came highly recommended, was properly qualified and knew what he was doing. He lifted and thinned the crowns of our large ash trees four years ago - there've been no new branches grow out from where the branches were reduced which is what happens when this is done wrongly and he has not had to come back to do more work. I have however recommended him highly to friends.
As a farmer's daughter I've watched farmers and farmworkers pollarding, coppicing, pruning etc all my life and have seen what happens when differents regimes are followed.
However, to be honest, unless I'd got several acres and had room for lots of trees, I wouldn't waste the limited space in my garden on a goat willow. It'll seed everywhere and while they can look fantastic en masse around watermeadows etc they're hardly a beautiful tree in isolation, especially when hacked about.