Crown Pruning Effects on Fine Root Development of Green Ash

2008 | P. Eric Wiseman, Virginia Tech

Arborists use structural pruning to improve crown architecture in young trees through selective thinning and reduction of live branches.  Pruning dose and timing are important considerations in writing a structural pruning prescription. Interestingly, the effect of pruning dose and timing on fine root dynamics has received little attention from arboriculture researchers. We used minirhizotrons (root observation tubes) to evaluate the effects of pruning dose and timing on fine root dynamics in small-caliper, field-grown green ash (Fraxinus pennsylanica). Four crown pruning treatments were evaluated: low-dose, growing season prune; high-dose, growing season prune; low-dose, dormant season prune; and high-dose, dormant season prune. Every two weeks, a miniaturized camera system was used to digitally photograph ash roots growing against the minirhizotrons. The digital images were analyzed using custom software to quantify root depth, physical dimensions, production and mortality rate, and longevity. The knowledge gained aids arborists to understand crown pruning effects on tree roots, which will bolster the scientific basis for future revisions of pruning standards and better inform pruning decisions in the field.

Year: 2008

Funding Duration: 1-3 years

Grant Program: John Z Duling

Grant Title: Crown Pruning Effects on Fine Root Development of Green Ash and Modeling Tree Growth to Better Predict Canopy Coverage in Urban Environments

Researcher: Eric Wiseman

Key words: Pruning; minirhizotrons; root growth

Peer Reviewed Publications from Grant:

  • Bartens, J., H. D. Grissino-Mayer, S. D. Day, and P. E. Wiseman. (2012). Evaluating the potential for dendrochronological analysis of live oak (Quercus virginiana Mill.) from the urban and rural environment – An explorative study. Dendrochronologia 30:15-21. View the Publication >
  • Bartens, J., P. E. Wiseman, E. T. Smiley. (2010). Stability of landscape trees in engineered and conventional urban soil mixes. Urban Forestry & Urban Greening 9(4):333–338. View the Publication >

General Audience/Trade Publications: none


  • Bartens, J. (2011). Live oak growth in the streets of Jacksonville, FL: Can we predict its future? Oral presentation at: Urban Tree Growth: An International Meeting and Research Symposium. View the Presentation >
  • Bartens, J., and P. E. Wiseman. (2010). Tree growth modeling to improve street tree size and canopy coverage predictions. In A. Koeser (Ed.), Proceedings of the 86th Annual International Society of Arboriculture Conference (CD-ROM Proceedings).