Predictive models are important tools not only for managers of urban street tree planting programs, but also for designers of urban infrastructure. Urban infrastructure often has elements that include restricted planting spaces, and ability to predict the Trunk Flare Diameter (TFD) of a mature tree can assist urban planners and natural resource managers in designing appropriate sites or selecting appropriate trees.  

Trunk Flare Diameter estimates can also be used to regenerate a list of stumps for removal. If you know the species and DBH of a tree that was cut-down, stump size at ground-line can be estimated using the calculator or the downloadable Excel based calculator. Click here to download a Microsoft Excel Trunk Flare.

Prediction of TFD has several potentially useful applications for urban planners and managers of urban street trees. 

  1. TFD models can be used to better inform the design or allocation of planting spaces with regard to tree species.  
  2. TFD predictive model is to identify potential tree and sidewalk conflicts using existing inventory data. 
  3.  TFD model is to generate a list of stump sizes for grinding. 
Trunk Flare Diameter

Stump & Trunk Flare Diameter Estimate Calculator

Select the species and enter DBH in inches
Click calculate to estimate the TFD size in inches


Estimated TFD
Research:
Hilber, D. R., North, E. A., Hauer, R. J., Koeser, A. K., McLean, D. C., Northrop, R. J., Andreu M. Parbs, S. (2020). Predicting trunk flare diameter to prevent tree damage to infrastructure. Urban Forestry & Urban Greening. https://doi.org/10.1016/j.ufug.2020.126645

Eric A. North, Gary R. Johnson, Thomas E. Burk. (2015). Trunk flare diameter predictions as an infrastructure planning tool to reduce tree and sidewalk conflicts, Urban Forestry & Urban Greening, Volume 14, Issue 1, Pages 65-71, ISSN 1618-8667, http://dx.doi.org/10.1016/j.ufug.2014.11.009.