The oldest method, which was develop prior to the availability of computers to fit the
equations, are whole stand average site curves. In this method, researchers collect
stand average age and the top height of the stand (the height of the dominant tree
in the stand). These observations are plotted on graph paper and "average guide
curve" drawn through the points. Then the curve was scaled to go through the
known index points. Most of the site index curves created before 1940 were done
this way. This method has a strong assumption in that the height averages the top
damage contained in the initial stands.