Constraining Irregular Shelterwood System for use at Haliburton Forest.

Abstract

Across Central Ontario, an increasing number of stands do not meet the criteria for management under the preferred system of Single Tree Selection. These stands are typically vertically and spatially heterogenous, and the traditional alternative of Uniform Shelterwood can be limiting. The Irregular Shelterwood System (ISS) is a new alternative that could allow for flexible sub-stand management.   However, the application of ISS can be insufficiently rigorous and make it challenging to meet the management goals of setting harvest intervals, auditing tree marking, predicting volume flows, or integrating sub-stand conditions with stand and forest level planning.  I present the current approach Haliburton Forest has taken to improve ISS outcomes at the stand and forest level.  This approach includes putting limits on the number and area of sub-stand treatments, novel stand analysis to identify dominant treatment needs, and a preference for the Extended or Expanding Gap variants of ISS over the Continuous Cover variant.    In aggregate these principles bring Irregular Shelterwood System closer to conventional silvicultural systems but emphasize differences that may allow for better stand diversity, growth, and value recovery.