Spacial patterns of fine root abundance in mixed larch-ash plantation

Abstract

Horizontal and vertical distributions of fine root abundance (mass per unit ground surface area) were investigated in a densely planted larch-ash-stripe-mixed forest on dark brown forest soil in northeast China. There was evidence for some degree of below-ground niche partitioning (or differentiation) between the two species in both the horizontal and vertical directions. The ash fine roots largely penetrated into the larch belt (larch sub-community) in surface soil (0–20 cm). indicating a possible inductive effect of larch ecological field on ash roots: while the penetration of larch fine roots into ash belt (ash sub-community) was much restricted, which reflected a negative influence of ash ecological field on larch roots. In the vertical direction of marginal soil, the ash fine roots were mainly distributed in topsoil with a vertical gradient similar to that as in the internal ash sub-community, but the larch fine roots were relatively compelled to deeper soil layers by the competition (or exclusion) of marginal ash trees. All the differences or complementarity were considered to the result of interspecific competition, which was important to the coexistence of the two forest species and the sustainability of mixed plantation.