Ectomycorrhiza density in coastal Japanese black pine stands with various understory vegetation

Abstract

Root and ectomycorrhizal density was examined in coastal Japanese black pine (Pinus thunbergii) stands. We set plots in 3 different types of understory vegetation in the stands: A-type; no-understory vegetation, B-type; herb layer less than 500 mm in height, C-type; shrub layer taller than 1000 mm and herb layer. The length of fine roots was shorter, and the number of the roots was less in the pine stands with dense understory vegetation. In such stands, the number of ectomycorrhizae per root-length (mm) and per unit volume of the soil sample (cm³) also reduced. These results suggested that vegetation succession caused decline of root and ectomycorrhizal activity. These parameters could be new simple indices for assessment of pine stand health.