Black walnut trees are prized for their high quality hardwood and tasty walnuts. Black walnuts are a top choice for furniture making and other woodworking that displays their beautiful dark finish and straight grain. This tree can fetch $10 or more per board foot! They are a relatively fast growing tree and may begin to produce nuts after 4-6 years, with larger quantities after 12+ years. They can reach heights of 100 - 130 feet.