Thanks guys.
It grew like that; there used to be a group of trees growing on the other side, shading it - hence the lean, but they died and were removed last fall. The one to the left was also taken down. The one growing through the shed is pretty bad too, will probably be brown by fall, but the owner is going to try and save it.
Was a bit of a pain, but the whole thing only took about an hour and a half. Roped the larger limbs and threw the small ones. The wood was already dried and light, so the blocks were easy to place.