Ash Reduction Model 2" Diameter Class                      
Version 1.4, Tara L. Eberhart, Andrew J. Storer, Linda M. Nagel  
Copyright Michigan Technological University   Version 1.4 Input Requirements  
10/3/2008   ASH Trees Only  
  Trees per Acre  
  Ash Species may be used, but if not known use Any Ash Species column  
  Forest Trees   Use Open Grown Model if most trees are receiving 4 or 5 sides of direct sunlight  
  2" Size Class Increments   Use Forest Model if working in a forest setting or most trees receiving sunlight on 3 sides or less  
  No. Trees Per Acre      
  DBH Class " Any Ash Species Green Ash and/or White Ash Black Ash % Surface Area                
  10           Retaining Small Trees      
  12           Target Percentages      
  14           Diameter Limit Cut      
  16           99%      
  18           95%      
  20             90%      
  22             75%      
  Total     *Cutting all ash down to this size limit  
    Retaining Large Trees  
    Target Percentages  
    Diameter Limit Cut  
    * Cutting all ash up to this size limit  
This version of the model serves to show what diameter limit cut would be needed in order to reduce the total surface area of ash trees in a stand by a desired amount.  
The bottom table of Retaining Large Trees is calculated from the same graph as the top table, with the percent axis reversed.  
This model can be used with Fraxinus nigra, or F. pennsylvanica and F. americana combined, or if species is only partially known, or not known at all, any ash species may be entered.  
Separate equations are used for individual species but the total ash reduction is combined for all the ash in the stand.  
Light Exposure and crown class have been accounted for in this model. The open grown version is appropriate if the majority of trees in the target area  
are open grown trees, or are receiving full sunlight on 4 or 5 sides including the top of the tree.  
The Forest version of the model is appropriate if the target reduction area is a forest setting and the majority of trees are receiving sunlight on 3 sides or less.  
Over 500 ash trees have had their specific morphology recorded to estimate total surface area which is a good indicator of total phloem available to emerald ash borer.  
This model only works with the ash component of a stand regardless of total stand size, other tree species presence, or how much ash there is present.  
Depending on management goals, this model can be used to determine a lower diameter limit cut to retain small trees,  
and an upper diameter limit cut to retain large trees. Surface area can be used as an estimate of phloem, a critical resource, available to  
emerald ash borer in a stand. Use of this model in management decisions will reduce the ash resource available to emerald ash borer  
by a target percentage and help maintain ash as a component in our forests and its genetic diversity  
Note: surface area reduction will reduce the amount of breeding substrate (phloem) in the stand by a target level,  
thereby reducing the population potential of eab, not ensuring remaining ash to be uninfested  

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