Soil and sugar maple response 15 years after dolomitic lime application

Dolomitic lime (CaMg(CO3)(2)) was applied in 1994 at rates of 0-50 Mg ha(-1) to sugar maples (SMs) (Acer saccharum Marsh.) in a base-poor and declining northern hardwood stand subjected to a high level of acid deposition in Quebec. The soil chemistry and the SM nutrition, growth, crown vigor, and regeneration status were evaluated 15 years after treatment. The soil chemical properties still responded strongly to lime after 15 years. Similarly, the foliar Ca and Mg concentrations were still higher for treated trees relative to the control trees. After 15 years, the mean crown dieback of trees decreased quadratically with the lime rate, from 39% for the control trees to a value of 1-3% for the lime rates of 5 Mg ha(-1) and higher. Additionally, the stem basal area increment for the limed trees was nearly double that of the unlimed trees in 2009. The lime application was also beneficial to the SM regeneration. The overall SM seedling density increased with the lime rate, being nearly twice as much in the 50 Mg ha(-1) (32 seedlings m(-2)) compared with the controls (16 seedlings m(-2)). The proportion of the SM seedlings to all of the other species increased quadratically from 22% in controls to more than 55% in the 5-50 Mg ha(-1) treatments. In contrast, the proportion of competitive species decreased quadratically with the lime rate, including American beech (Fagus grandifolia Ehrh.) for which the proportion in the treated plots (24%) was nearly half the proportion observed in the controls (46%). However, increase in stem density of regeneration and canopy closure in response to lime application limit the development of the regeneration which did not benefit in terms of diameter and height. These results show that a single lime addition has long-term beneficial effects on the soil chemistry and the SM nutrition, vigor, growth, and regeneration in base-poor and declining northern hardwood stands. Moreover, the results confirm that liming is an essential tool to restore the SM representation and health in acidic and base-poor soils. Crown Copyright (C) 2012 Published by Elsevier B.V. All rights reserved.