It may feel like summer has barely arrived but the fall planting season is just 10 weeks away. This is a fitting time to get familiar with industry accepted standards for nursery stock (if you aren’t already). The American National Standards Institute‘s Z.60, American Standard for Nursery Stock establishes professional standards for trees and shrubs grown in the nursery trade.

This 109-page publication was drafted and edited by a committee of horticultural researchers and green industry professionals from across the country and was recently revised in 2014. Best of all, the standard is published by AmericanHort and free to download from their website.

ANSIz60The Z.60 addresses details about plant quality that might go unnoticed by a non-tree expert, which include but are not limited to:

  • Classifications for different types and sizes of woody plants
  • Root ball dimensions
  • Size and spacing of branches
  • Ratio of stem diameter to root ball size
  • Height-to-spread ratios for tree canopies
  • Conifer-specific standards
  • Parameters for evaluating plant quality

Here are some potential applications…

If you’re purchasing trees to plant, be sure they meet the standards before you buy. If your city requires tree planting as part of the development process, then specify that all code-required trees meet the standards. Municipal inspectors, code enforcement officers or city foresters can use the standards for guidance on when to accept or reject those code-required trees. And lastly, any contract for tree planting is not complete without a provision that requires adherence to the Z.60 standard.

The urban forest is only as good as the trees we plant in it, so let’s be planting the best possible trees.