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    Climbers' CornerTree Academy

    Nineteen Years of Structural Soils


    The theory and research associated with the growing medium concept commonly referred to as Structural Soil has been available now for 20 years.  This presentation will highlight the progress of the technology in British Columbia region of Canada where structural soil has been used extensively since 1995.    The discussion will review what we have learned, the good and the bad.   

    In 2001, we provided a presentation to the 1st Milwaukee ISA conference that outlined what we had learned in the first six year of use.  It seems appropriate that an update of what has been learned after 19 years of use would be appropriate for this conference.    

    Subsequent to the initial installations, a number of critical advancements in the methods, materials and techniques have been tested and applied.   With the evolution of managed applications, the acceptance of Structural Soil has grown to the extent that this material has become an engineering standard that in many communities is no longer optional for trees installed in hardscape situations.  It has been generally acknowledged that more structural soil has been installed under the sidewalks of the British Columbia region than the rest of north America combined.

    This presentation will review the detailed design process, material selection, and make available examples of various installation methods.  We will also include discussion with regard to our experience in obtaining engineering approval for the use of this material under city streets and sidewalks.  Innovation in the installation process will be discussed  and critique of the limitations that have been identified will be provided. We will also provide a critical assessment of which tree species have proven to be the better selection for growth in Structural Soil.

    Recent information from other areas of north America suggest varied results in the use of similar materials.  The general consensus in British Columbia is that Structural Soil is working well but there have been exceptions.  Structural Soil continues to be specified regularly and with far more cost benefit than any of the other options that have become available in the recent past to the design profession.  Our discussion will reflect on why the British Columbia experience has been superior to what has been reported in other areas.    


    ISA Certified Arborist       

    Michael Mills is a Consulting Arborist certified by the International Society of Arboriculture.  He specialises in urban forestry and arboriculture, particularly tree preservation, tree evaluation and alternative tree installation design.   Michael also provides landscape consulting services focused on review services for newly installed landscapes.   Michael is well known as an advocate for sustainable landscape and urban forestry practices with over 35 years of experience in related fields of study.  He continues to work toward ongoing improvements in the practise of arboriculture and urban forestry in close association with the design fields of Architecture, Engineering and Landscape Architecture.  His work with alternative tree preservation techniques such as pre development root pruning and alternative tree installation designs such as structural soil have been recognized and adopted by many of the lower mainland municipalities.  He has also been recognized internationally by invitation to present his views on several topics at three international training conferences, numerous regional conferences and at the Canadian Urban Forestry Conference in Lake Louise.  Michael also owns and operates a nursery operation on the Sunshine Coast.    


    Climbers' CornerTree Academy

    ©International Society of Arboriculture 2009-2018
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