when turned green,heart and sapwood of cherry,damson,greengage,plum etc;are all soft and easy to turn,with no noticeable difference between heart and sapwood,the only two things to watch is all the sap coming out,its like being in a shower its so wet and dead knots inside the trunk/branch that your turning can cause a wavy cut to set up which can be difficult for a novice to rectify,with this i find its easiest to cut from the opposite direction with fine well controlled cuts until the ridges set up by the wobble are cut away.