The Pro-B Method Application of Uneven-Aged Silviculture

Uneven-aged Silviculture:
The Proportional Basal Area Method


The selection of a silvicultural system should be based on a landowner’s objectives, the silvical characteristics of crop trees (and their competitors), any constraints on the treatments available for use, as well as any potential stand damaging agents.  So, what situations might suggest, or require, that a manager select an uneven-aged system?

An admittedly incomplete list might include:

  • Even-aged systems are deemed unacceptable to the landowner
  • A desire to maintain the aesthetics of the stand
  • The need for a short-temporal-scale ‘sustainable’ system
  • Wildlife habitat considerations
  • Policy/legal requirements
  • Selection may be the most suitable for the desired species


However, even if an uneven-aged approach to managing a forest seems to be the most appropriate choice, many natural resource managers have little or no experience with the application of selection silviculture.  The Pro-B method was developed to provide land managers with a relatively simple tool for applying selection silviculture in the field.  Like any tool, Pro-B can be applied inappropriately.  To reduce that potential, we present the ecological foundations for the system so that the practitioner can determine whether selection is appropriate in their particular situation.  Common misconceptions related to selection silviculture are described to further reduce the potential for failure.  In addition, we have provided some background on the traditional approaches for regulation in uneven-aged stands and include a bibliography of scientific literature related to selection silviculture for those who wish to delve deeper into the history and current research on the subject.  Still, the primary reason for the development of this site was to document and freely distribute the Pro-B methodology.  We hope you find it useful and welcome any suggestions for improvement of this site or questions that would help us to clarify the procedure.

This website was developed with support provided by the USDA Forest Service under coop agreement 14-CA-11330123-081, Pro-B Expert System.

Last modified: October 19, 2018