RT Journal Article SR Electronic T1 Reducing Surface Rooting of Trees with Control Planters and Wells JF Arboriculture & Urban Forestry (AUF) JO JOA FD International Society of Arboriculture SP 165 OP 171 DO 10.48044/jauf.1985.037 VO 11 IS 6 A1 J. Alan Wagar YR 1985 UL http://auf.isa-arbor.com/content/11/6/165.abstract AB Control of surface rooting was explored in a study of fruitless mulberry (Morus alba) and zelkova (Zelkova serrata). After 3½ growing seasons, average amounts of roots were reduced substantially in the top 8 inches of soil by PVC control planters and by wells that placed trees 18 inches below grade. Among trees in planters and wells, however, amounts of surface roots differed greatly, and the tendency of roots to return to surface layers may be partly associated with soil compaction and poor aeration. Mulberry roots returning to the surface layers were, on the average, smaller and zelkova roots fewer than the unconstrained roots of control trees of the two species. For a given trunk size, mulberry roots were much more massive than zelkova roots. Avoiding species with massive roots remains extremely important in selecting street trees.