RT Journal Article SR Electronic T1 Effects of a Deep Layer of Mulch on the Soil Environment and Tree Root Growth JF Arboriculture & Urban Forestry (AUF) FD International Society of Arboriculture SP 242 OP 245 DO 10.48044/jauf.1991.056 VO 17 IS 9 A1 Watson, Gary W. A1 Kupkowski, Gary YR 1991 UL http://auf.isa-arbor.com/content/17/9/242.abstract AB After two years, no detrimental effects were found from application of 0.45 m (18 in) of wood chip mulch over soil in which the roots of trees were growing. Soil temperature, moisture and oxygen diffusion rate (ODR) were similar to soil without mulch. Root density in mulched soil was not different from unmulched soil; additional roots had proliferated into the mulch.