Which comes first, the root or the crack?

The Ohio State University and the City of Cincinnati Park Board conducted a study of street trees in Cincinnati, Ohio, U.S., during the summers of 1999 and 2000. Four genera of trees were examined from four different plant families. Approximately 600 trees planted within the past 20 years were observed. The condition of the nearest sidewalk joint and the incidence of a root for Quercus (oak), Koelreuteria (goldenraintree), Zelkova (zelkova), and Gleditsia (honeylocust) were observed. All genera responded similarly in that roots were more likely to be found under a crack in the sidewalk than under an intact sidewalk." Co-authors are: T.D. Sydnor, M. Knee, R. Hunt, and B. Bishop.

[Ti: Which comes first, the root or the crack?]
[Au: DAmato, N.E. et al., , ,]
[So: Journal of Arboriculture 28(6):277-282.]
[Ky: Maintenance]]

[Issue/Page: 28(6):277-282]