Age-diameter relationships of Quercus species in relation to edaphic factors in gallery forests in Northeast Kansas

Age-diameter relationships were evaluated for Quercus macrocarpa and Q. muehlenbergii in relation to soil and topographic factors in 18 gallery forest stands in northeast Kansas. Tree diameter was significantly correlated with age (r² = 0.33-0.96, P < 0.05) for Q. macrocarpa and Q. muehlenbergii in 81% and 85% of the stands, respectively, when seven or more individuals of either species were surveyed, indicating that variation in growth rates for these species was low within most of the stands. However, considerable variation in growth rates of these species was evident between stands, which was not explained by differences in stand density. High growth rates for Q. macrocarpa were correlated (P < 0.05) with low topographic slope (r² = 0.54), and low available soil NH₄ (r = 0.73) and NO₃ (r = 0,72), whereas high growth rates for Q. muehlenbergii were correlated with high K (r = 0.62), suggesting that edaphic factors influence growth rates of these species.