Yew can grow to be thousands of years old, its secret is that it can heal its injuries. So strong is this ability to heal that if two branches grow to touch they rub, damage each other, heal and fuse together then grow on as a single member. All through large sections you will then find trapped bark where once outside branches are now totally inside, snapped off ends and all. But the grain effects around such a feature are incredible. Hell on the chisels though.