The present investigations were made from 11 trees of Quercus alba, 17 trees of Q. montana, 16 trees of Q. velutina and 9of Q. borealis maxima. All specimens were taken from the knobs area of Bartholomew and Brown counties in Indiana, from stumps left by lumbering operations carried on from July to September: 1934. Sections were brought to the laboratory and measurements were made with a binocular microscope suspended over the section. The annular ring widths of eight equidistant radii were taken on each of the 53 sections measured. During the measuring, medullary rays were followed instead of geometrical radii. In this manner the width of the annular growth was taken in a direction eliminating the error of oblique measurement. When a radius was completed, a number tag was placed at the end of the radius. This allowed for a recheck to be made at any desirable time. Annular ring measurements were taken of the years 1909-1933 inclusive, a growth period of twenty-five years. The measurement of eight radii per section aided in eliminating the errors of unequal growth along different radii in the same tree.