Can Missouri Gravel Beds Function as a Year-Round Production System to Improve Tree Root Structure and Fine Biomass vs. Traditional Pot in Pot Production Methods

The Missouri gravel bed (MGB) concept originated from the practice of 'healing in' the roots of plants into moisture retaining material until the landscape site was prepared. While the initial MGB design was used just to extend the bare root tree planting season, this project proposes to test the ability of the gravel bed method to function as a year round production option for growers in Iowa. The objective is to grow trees with more fibrous root systems which are easier, more vigorous and economical to transplant and to improve the yearly above and below ground growth, making better quality trees marketable in less time. The aim is to test and demonstrate to growers the efficacy of this new tree production method as a way to reduce production costs while providing technical information to speed the adoption of the production method. If funded, this project will inform multiple industries including nursery, municipalities, and natural resource agencies and we would anticipate that it would produce trees with a higher success rate of survival in the landscape. This study is designed to provide initial results within a 30 month time frame and will utilize resources (established irrigation mainlines, mowing, weed control and other infrastructure) at both the Iowa State University (ISU) Forestry Greenhouse and ISU Horticulture Research and Demonstration Farm. It will be incorporated into current ISU Extension and Outreach programming which will facilitate information exchange and adoption across a wide spectrum of the industry. Written material will be disseminated at local, regional and national nursery industry meetings as well as online at the Forestry Extension website. Missouri gravel beds are not new, but the use and awareness of them has increased dramatically in the last 10 years. Researchers in Missouri and elsewhere have shown the efficacy of the systems but are unaware of research that evaluates the year-round seedling to transplant production scenario. A better understanding of the MGB system as a viable commercial production option and the ability of these systems to balance root structure, fine root production, and above ground growth to economically produce a merchantable tree from a bare root whip solely grown in a MGB is needed. For growers, retailers, municipalities, and homeowners the impact of such a production system is potentially substantial. The MGB system could overcome several disadvantages found in the three most common production systems. It should allow for substantially more roots to be retained than the B&B method, create a plant with fine root mass that equals or exceeds container grown seedlings with virtually none of the architectural problems (e.g. girdling roots) that plague most container derived trees in 20-30 years. Additionally, it should eliminate dormant season harvesting and storage challenges (temperature, and humidity) until planting that limits the bare root production method. Although upfront costs associated with the MGB production method might be higher, the entire system is reusable and if trees are produced faster, are of superior quality, are more economical to ship and plant because they are lighter and more compact, the return should be greater for the grower, municipalities, and landscapers. Trees produced from this system should also have higher transplant success rates reducing the 1 year plant guarantee replacement costs. Long-term, the impact will be realized with healthier trees that are able to withstand both disease and insect pressures on the landscape and harsh landscape settings while increasing benefits to air and water quality.

  • Supplemental Notes:
    • Add 528


  • English


  • Status: Completed
  • Funding: $38633.00
  • Contract Numbers:


    ISU proposal 129831

    Addendum 528

  • Sponsor Organizations:

    Iowa Department of Transportation

    800 Lincoln Way
    Ames, IA  United States  50010
  • Project Managers:

    Masteller, Mark

  • Performing Organizations:

    Iowa State University

    Iowa State University Forestry Extension
    339 Science II
    Ames, Iowa  United States  50011-3221

    Iowa State University, Ames

    Institute for Transportation Studies
    2711 S. Loop Drive, Suite 4700, Program for Sustainable Pavement Engineering and Research (PROSPER)
    Ames, IA  United States  50010-8864
  • Principal Investigators:

    Randall, Jesse

  • Start Date: 20141115
  • Expected Completion Date: 20181231
  • Actual Completion Date: 0
  • Source Data: RiP Project 38659

Subject/Index Terms

Filing Info

  • Accession Number: 01547621
  • Record Type: Research project
  • Source Agency: Iowa Department of Transportation
  • Contract Numbers: 2100000T001, ISU proposal 129831, Addendum 528
  • Files: RIP, STATEDOT
  • Created Date: Dec 12 2014 1:00AM