Response of Shade Trees Grown in In-ground Containers to Three Container Substrates

Abstract

Abstract Two-year-old branched seedling whips of green ash, Fraxinus pennsylvanica Marsh. and European birch, Betula pendula Roth, were grown for two seasons (1991 and 1992) in 38-liter (# 10) rigid, plastic, in-ground containers in three different substrate treatments: 10%, 50% and 100% soil, containing 10:30:60, 50:30:20, or 100:0:0 of field soil:sphagnum peat:ground pine bark, respectively. Trees were also planted directly into the soil (field-grown) to serve as a baseline control treatment. Top dry mass, trunk diameter and root dry mass in 1991 and 1992 and two size categories of root dry mass (<3 and 3<6 mm) in 1991 were consistently greatest for container-grown trees in the 10% soil treatment and least in the 100% soil treatments. Corresponding results for the 50% soil treatment were intermediate between the other treatments or similar to the 10% soil treatment. In 1991, the top dry mass and trunk diameter of both species grown in containers with 10% soil and in 1992, the top dry mass of ash, in the same treatment, were greater than those of field-grown trees.