RT Journal Article SR Electronic T1 Abstracts JF Arboriculture & Urban Forestry (AUF) FD International Society of Arboriculture SP 18 OP 18 DO 10.48044/joa.1981.7.1.18 VO 7 IS 1 YR 1981 UL http://auf.isa-arbor.com/content/7/1/18.abstract AB