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Idaho Class I Streamside Tree Retention Rule or the “Shade Rule”

For more than ten years the Idaho Forest Practices Act Advisory Committee (FPAAC) has been working to develop a new Class I Tree Retention rule.  The process began when the Idaho Department of Environmental Quality (IDEQ) first recommended that FPAAC and the Idaho Department of Lands (IDL) needed to address some potential shortcomings in the current rule.  The findings of IDEQ were presented to FPAAC in 2000 and 2004 following quadrennial water quality audits.  More than ten years have been devoted to finding and evaluating possible protective measures to replace or modernize the standards in the existing rule.

Class I streams are defined as being fish-bearing or used for domestic water use, therefore, the level of protection is considerably higher.  Shade over a stream is considered important in Idaho because many of our fish species require cool water temperatures to survive and shade is associated with cooler water temperatures.  Additionally, it is considered beneficial for streams to have trees occasionally fall into or across the stream to provide large woody debris for structure and nutrient cycling.  The new rule was designed to better provide for both shade and large woody debris recruitment.  FPAAC decided to express and measure streamside tree density with Relative Stocking in part because it is already being used as an accepted measure of shade in riparian environments.  Relative Stocking (RS) is a more robust measurement than traditional density measurements such as trees per acre and basal area in that it considers density, size, and site productivity.

In 2012, IDL began the rulemaking process that included input from the public and many statewide stakeholder groups.  Through this process a rule was created, based on scientifically sound principles, using actual Idaho forest stand data.  The rule contains stocking requirements that provide the necessary threshold of shade to protect streams and assure large woody debris recruitment for stream structure.  The rule provides two management options for landowners to choose from, offering a level of flexibility that is unique to Idaho.  Additionally, the rule creates two zones within the Stream Protection Zone (SPZ) of the Class I stream, an inner and an outer zone.  The purpose of creating two zones within the SPZ is to provide greater protection to trees closer to the stream and therefore of greater importance to the stream for both shade and large woody debris recruitment.

Relative Stocking, expressed as a percentage, shows the extent to which trees utilize a plot of forestland.  Simply stated, Relative Stocking is essentially the percentage of stocking that a stand is currently at relative to that stand’s capacity.  So a stand at 60% relative stocking is at about 60% of its capacity of trees.  This point is when stands are generally considered fully stocked and land managers begin to consider harvesting.  Because there is a substantial difference in the carrying capacity of forestlands in Idaho, five forest types were identified to stratify the state.  Each of these forest types represents several habitats that exist on the landscape and dryer less productive sites have different tree retention requirements than wetter more productive sites.

IDL is busy developing the tools and resources necessary to help landowners and industry professionals implement the new rule on the ground.  These tools will include spreadsheets and worksheets for calculating RS on the ground as well as a Forester’s Forum publication explaining the rule and how to implement it on the ground.  The IDL is also restoring three full-time Private Forestry Specialist positions to help landowners and operators implement the new rule.  Already more than 1,000 people have attended presentations provided by IDL and our partners to introduce the new rule to loggers, landowners, and foresters.

A monitoring program to measure the effectiveness of the new rule is being developed by IDL, the Department of Environmental Quality (IDEQ), and the University of Idaho.  The purpose of this monitoring is to provide results to FPAAC about the effectiveness of the new rule so that it can be evaluated in the future and adjustments made as warranted.

The new rule will take effect on July 1, 2014.  We at IDL will strive to help landowners and operators implement this rule.  It is important we show that our integrated rulemaking process has been successfully applied and has resulted in a rule that is implementable and understandable.  It is also important that landowners have the management flexibility to continue to manage their property while providing protection to public resources.

By Archie Gray, CF, Forest Practices Program Manager, Idaho Department of Lands

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