The present study is an attempt to determine what rainfall periods show the highest degree of correlation with growth in three species of deciduous trees from Brown County, Indiana, and to determine which area of the tree, i.e., the top or the bottom, gives the closest growth-rainfall correlation.

Fuller has shown that there is a close correlation between precipitation for the calendar year in Illinois and increase in diameter in Quercus borealis maxima as shown by thickness of its annual growth rings. Kleine, Potzger, and Friesner, using 11 trees of Quercus alba, 17 of Quecrcus montana, 16 of Quercus velutina, and 9 of Quercus borealis maxima, found a correlation between annual growth and rainfall for the months June, July and August. This work, as in the present study, was done on sites with considerable relief and hence subject to excessive run-off.