Shoot and Root Growth of Three Tree Species in Sidewalks

Abstract

Three tree species (Tilia cordata Mill. ‘Olympic’, Acer campestre L., and Malus sp. Mill. ‘Adirondack’) were grown in a standard sidewalk pavement profile, an experimental sidewalk profile (SSM), and in the field. Root systems in the paved treatments were harvested after three years to analyze root length, root density, and profile distribution. SSM tree foliage quality (measured by SPAD 502) and shoot extension measured in the second and third years were not different than those of the field control trees. Tree foliage quality and shoot extension were reduced in the standard sidewalk profile. There was an increase in root length of Acer and Tilia in the SSM profile versus the standard sidewalk profile and an increase in depth of the root zone for all species. The results indicate several advantages in root and canopy growth for street trees grown in the experimental profile compared to the standard sidewalk pavement profile.