Soil properties and maple–beech regeneration a decade after liming in a northern hardwood stand

Soil properties, regeneration, sugar maple (SM, Acer saccharum Marsh.) crown dieback, and light interception were evaluated following dolomitic lime application (CaMg(CO3)2; 0, 2, 5, 10 and 20 t ha−1) in a base-poor and declining northern hardwood stand of Quebec (Canada). Ten years after liming, soil pH, cation exchange capacity and base saturation increased with the lime rate. Meanwhile, concentrations of exchangeable K, Na, and acidity (0–20 cm) decreased. Concentrations and content of total carbon, organic matter, and total N decreased in the top sampled soil layer, mainly for the highest lime rate. Mean crown dieback of SM ranked from 0 to 3.4% among lime treatments, while it ranked 18.4% for the unlimed controls. Light interception by the canopy responded with an opposite pattern to crown dieback, with higher interception in lime treatments and lower in control. Proportion and diameter of SM regeneration stems increased with lime rate while proportion of American beech (AB, Fagus grandifolia Ehrh.) regeneration stems decreased in the understory. Height and stem diameter of the three taller regeneration stems (mainly AB) in each plot were inversely correlated with lime rate. Overall, the results suggest that the increase in soil fertility following liming had a beneficial effect on SM regeneration within 10 years, even if light availability was lower under treated SM than under control, and had an overall negative impact on AB regeneration.