It will ultimately grow so large that it will be impossible to remove it, and there might be some adverse effect on the tree. How big's the pine? Wisteria are pruned in mid to lat summer, cutting back new laterals by a half, and then again in January, cutting back the new growth made after the first prune to two buds. However, if you're worried abou the tree, it may be best to give it the big final prune! Phil J

thanks Phil; I will try the former advice first :) the tree is about 6 meter high; but you should see the way Wisteria has wrapped the trunk so tightly and broadly; I wonder if we prune it half way along the trunk rather than a big final one, would it shoot anew?