A method for quantitatively evaluating the successional relationships which exist between species was tested on data from Menominee County, Wisconsin. The method is based upon an examination of the changes in interspecific association which occur when successively larger diameter classes of one or both species are used as the basis for the calculation of an association index. With this method it is possible in most cases to determine which species tend to replace which others. In addition, by averaging replacement tendencies in various ways, index values can be arrived at which express the degree to which a particular species may be characterized as pioneer or climax. The results of the analysis agree well with other studies on succession in these forests. This method should prove useful in elucidating successional relationships, especially in areas where these are not well understood.