However, with Hard Maple, it is actually the sapwood that is valuable for lumber and other wood products, not the heartwood.
In other words, Hard Maple lumber is cut from the outer ring of the tree, therefore bigger sap areas are preferred by lumber mills and timber buyers. Setting aside whether or not a log could sell as veneer, in general, the smaller the heartwood of a Hard Maple tree, the more valuable it is. The heart size of Hard Maple trees depends on many factors and is usually hard to predict before cutting.Determining Hard Maple Quality
Because you can't tell how big the heartwood is relative to the sapwood, Hard Maple is one of the more difficult species' of hardwood timber to value while standing. It is just impossible to know how they will cut. While not fool-proof, there are some rules of thumb for valuing Hard Maple while it is still standing. In general, the more tight the bark on a Hard Maple tree is, the more likely it is to contain high quality wood. Locations with more of certain types of minerals can cause the hearts of Hard Maple trees to grow larger. Further, wetter locations tend to grow Maple with larger hearts. Two Maple trees from the same tract of land and stand of timber can present radically different rations of heartwood to sapwood. Hard Maple is best when it is small hearted, tight-barked and bright white in color. In the picture below the two trees on the left are very high quality, small-hearted and of veneer quality, while the tree on the right has a large heart and will not yield high quality Hard Maple lumber.