Different pieces of wood cut from a large tree may differ decidedly, particularly if the tree is big and mature. In some trees, the wood laid on late in the life of a tree is softer, lighter, weaker, and more even-textured than that produced earlier, but in other trees, the reverse applies. This may or may not correspond to <answer>heartwood</answer> and sapwood. In a large log the sapwood, because of the time in the life of the tree when it was grown, may be inferior in hardness, strength, and toughness to equally sound <answer>heartwood</answer> from the same log. In a smaller tree, the reverse may be true.
In a large log, will the heartwood or sapwood usually be stronger and tougher?
heartwood