Litterfall and soil characteristics in canopy gaps occupied by vine maple in a coastal western hemlock forest

Abstract

In some low-elevation coastal British Columbia forests, canopy gaps can be occupied by the hardwood tree species, vine maple (Acer circinatum). The objective of this study was to determine how vine maple gaps influence litterfall, litter decomposition, and forest floor and mineral soil properties. Measurements were made on six vine maple gaps paired with six conifer canopy plots. Vine maple gaps had significantly less conifer litterfall during the autumn, higher pH, and higher concentrations of Ca, Mg and K in the forest floor, thinner forest floors, and a weak tendency for lower C/N ratios, higher pH values and higher total N concentrations in the surface mineral soil. Vine maple litter was found to decompose significantly faster than conifer litter and to have higher concentrations of N, P, Ca, Mg, K, Fe and Zn. Decomposition rates of vine maple litter and of conifer litter did not differ significantly between vine maple gap and conifer canopy plots. Larger vine maple clones had significantly thicker forest floors with higher concentrations of Ca, and higher N concentrations and lower C/N ratios in the surface mineral soil than gaps with smaller vine maple clones. The results indicate that vine maple gaps may improve the nutritional status of the sites that they occupy within conifer forests. Key words: Litterfall, litter decomposition, soil-plant interactions, vine maple, canopy openings, canopy gaps