The dramatic coloring in this maple, Acer Rubrum,  is caused by the Ambrosia Beetle. The beetle causes pinholes 1/100" - 1/4" in diameter and attacks only recently killed/cut trees, logs, and green lumber. They usually bore into the sapwood of both hard and softwoods although sometimes they affect the heartwood. Interestingly, the beetle does not consume the wood; rather, when he excavates his "tunnel", he introduces two types of fungus.

The first grows on the walls of the "tunnel" and it is this fungus which is consumed by the beetle for nourishment. The fungus is called Ambrosia and the name was passed on to include the beetle. The second fungus is a staining fungus which, if introduced, causes greenish-gray or bluish-black staining around the pinholes.