Stem flow chemistry of Picea glehnii, Abies sachalinensis and Alnus japonica and its effect on the peat pore water chemistry in an ombrogenous mire in Ochiishi, eastern Hokkaido, Japan

Abstract

We investigated the chemical properties of stemflow of Picea glehnii, Abies sachalinensis and Alnus japonica as well as peat pore water chemistry, including the distance and depth profiles of pore water chemistry, in an ombrogenous mire. The effect of stemflow on the peat pore water chemistry was clear at the stem base in the peat forest in the mire, and the peat pore water around the stem base of a tree had its own chemical properties specific to each species. P. glehnii showed the highest concentration of salts both in stemflow and peat-pore water, whereas A. japonica showed the lowest concentrations; however, the gradient of the chemical environment from the stem base to outside of the canopy is formed. The peat pore water chemistry under the canopy was mainly controlled by the chemical processes diluted by the abundant peat pore water; the stemflow movement in the high water content of the peat was more slowly because of the flat topography (< 1°). This would be due to the fact that the chemicals in stemflow would be diluted by the abundant peat pore water. The spatial heterogeneity of chemical environment between microsites within forested peatland would be also contributed indirectly through the control of microorganism activity, and nutrient regeneration mediated the surface water and the stemflow of the dominant canopy trees.