TY - JOUR T1 - Causes and Consequences of Deep Structural Roots in Urban Trees: From Nursery Production to Landscape Establishment JF - Arboriculture & Urban Forestry (AUF) SP - 182 LP - 191 DO - 10.48044/jauf.2009.031 VL - 35 IS - 4 AU - Susan D. Day AU - Gary Watson AU - P. Eric Wiseman AU - J. Roger Harris Y1 - 2009/07/01 UR - http://auf.isa-arbor.com/content/35/4/182.abstract N2 - Recent research has improved our understanding of how structural roots of landscape trees respond to being located abnormally deep in the soil profile. This condition is widespread among landscape trees and may originate during nursery production, at transplanting into the landscape, or when construction fill or sediment deposits bury root systems of established trees. Deep structural roots sometimes hinder successful establishment of trees, occasionally enhance establishment, and often have little or no effect on growth or survival. When trees respond to deep structural roots, effects are sometimes observed when root collars are as little as 7.5 cm (3 in) deep. In some cases, deep structural roots are implicated in girdling root formation, but research in this area is quite limited. This review describes scientific progress in our understanding of deep structural roots and encompasses their history, causes, and significance, as well as interdisciplinary efforts to address deep planting and tree response during establishment to deep structural roots. A theoretical model of short-term tree response to deep structural roots is presented that helps explain these conflicting outcomes and provides a decision framework for practitioners evaluating trees with deep structural roots. ER -