Seasonal fluxes of some ions through the overstory, underbrush, and organic soil horizons of an aspen-birch forest

A study was made of the water and chemical fluxes in a predominantly deciduous forest at Chalk River, Ontario. The chemistry of water moving to the soil through trembling aspen, large‐tooth aspen and paper birch is strongly modified by interaction with all major components in the system: the overstory leaves and trunks, the underbrush stems and leaves, and the organic plus upper mineral soil horizon. The dominant controls on the chemistry of water reaching the forest floor are those exerted by the overstory. Hydrochemical changes through the underbrush are, generally, of the same type as those through the overstory, but of a smaller size. A significant, positive relationship was found between the hydrogen ion flux imposed on the overstory, and the net loss of calcium, magnesium, and potassium from the canopy, showing that acid deposition is having an effect on the export of these nutrients from the canopy.