WOODWORKING
Heartwood
Heartwood is usually graded lower than sapwood because it retains more imperfections and
knottiness than sapwood.
Best used for exposed conditions or as structural members because it is stronger and more durable
You can identify lumber made of heartwood simply by looking at the end grain of the board. If
the grain pattern has tight arcs, chances are it has been cut from the inner layer where the growth
rings of the tree are a lesser diameter.Milling Lumber:
As illustrated below, wood is milled from a tree longitudinally (i.e. the full length of the tree). Notice the
growth rings. The heartwood growth rings form smaller, tighter circles than the sapwood. Now, notice how
the larger beams are milled from the center of the tree, while the thinner boards used for veneer or decorative
pieces are cut from the out layers.
The illustration on the right shows how lumber is milled from a
tree to get the most use of the wood.
Unit II: Understanding Wood