Production playbook

The 2014 edition of the American Standard for Nursery Stock (ANSI Z60.1 – the Standard) has just been completed. The updated version will be published later this year by AmericanHort. The purpose of the Standard is to provide buyers and sellers of nursery stock with a common terminology in order to facilitate transactions involving nursery stock.

Growers need to be aware of the changes in this latest edition. The top five most important revisions to the 2004 edition are:

1. To make the Standard easier to use, new tables for each plant type include multiple specifications for each plant size specification, including minimum root ball size, various measurement ratios such as caliper:height or spread:height, minimum number of canes or branches, and minimum container class and in-ground fabric bag size.

2. Minimum requirements for all nursery stock in a new “General Standards” section include:

• Good living condition
• Typical in habit for the species in the region of the country in which it is grown
• Correct identification (by genus, species and, if applicable, cultivar) – new to this edition
• Substantially free of damaging insects and diseases – new to this edition
• Pruning cuts must be done in accordance with related consensus standards – new to this edition
• Type 1 and Type 2 shade trees may not have co-dominant stems in the bottom half of the crown – new to this edition
   

3. Clarification of the method for measuring caliper and the relationship between root flare and the soil line.

4. Changes to specifications for in-ground fabric bags and expansion of their application to all plant types.

5. Recognition of containers that “encourage or manipulate root growth” and recognition of fabric as an acceptable container material.

Other important revisions were included in the 2014 edition.
 

Aggregated plant type tables

The tables in the 2004 edition of the Standard were structured to address a single specification for multiple plant types or to address a single specification of a single plant type. New plant type tables in the 2014 edition aggregate the majority of the specifications for each separate plant type, by plant size interval, including minimum root ball diameters and depths, various measurement ratios (e.g., caliper:height or spread:height), minimum number of canes or branches, minimum and maximum container classes, and minimum in-ground fabric bag size.
 

Minimum acceptable container class specifications

The 2004 container class (size) tables provided a range of plant sizes that corresponded to each container class, and specifiers were “encouraged to specify a container class . . . in which the desired plant size falls between the minimum and maximum plant size (interval) shown.” Conversely, the new plant type tables provide minimum and maximum container class specifications for each plant size (interval) specification.

As a result, to the extent that nursery stock has been grown, specified, and sold using the 2004 “maximum plant size” in the smallest container listed, the nursery stock might not comply with the applicable 2014 plant type table. However, it is important to note that such plant size:container class combinations would likely have “excessive root growth encircling the inside of the container,” which was prohibited in the 2004 edition and is included in the 2014 edition.
 

New section 1 - general standards

The 2014 edition includes a new “Section 1 – General Standards” that applies to multiple (or all) plant types and is primarily compiled from text repeated in several plant type sections and in the Foreword of the 2004 edition.

Measuring caliper – Long-standing text describing where caliper is measured has been revised to clarify that the “4 inch” caliper size includes the entire interval “up to but not including 4½ inches,” such that, “If the caliper measured at 6 inches is 4½ inches or more, the caliper shall be measured at 12 inches above the ground level, soil line, or root flare, as appropriate.

Root flare “at or near” ground/soil line – Text has been added regarding the relationship between the root flare (“at or near”) the soil level for consistency of the method for measuring caliper with the methods for measuring height and root ball depth that were in the 2004 edition. Growers should note that trees with root flares “at or near” the ground or soil line will have larger caliper and height measurements than trees with primary structural roots well below the ground or soil line and, therefore, higher value in the marketplace.
 

Fabric bags

Several revisions to the 2004 edition relate to “fabric bags,” including:

• Clarification throughout the 2014 edition that all references are to “inground” fabric bags
• Addition of “in-ground” fabric bag sizes under 10-inch diameter (5-inch and 8-inch)
• Addition of in-ground fabric bag size over 24-inch diameter (30-inch)
• Smaller depth minimums for in-ground fabric bag sizes in relation to diameter
• Addition of in-ground fabric bag specifications for certain plant types that were not in the 2004 edition
• Recognition that fabric is an acceptable material for “above-ground” containers, as long as the root system meets the genera requirement for container-grown nursery stock (see “Recognition of Certain Containers,” below)

Minimum root ball diameters for sheared evergreens The 2004 edition required minimum root ball diameter specifications for “sheared” evergreens to be determined by cross-reference to the minimum root ball table applicable to Type 1 and Type 2 shade trees. For some plant types, integrating the specifications from the 2004 shade tree table into the new plant type tables resulted in inconsistent minimum root ball specifications for sheared and non-sheared evergreens of the same caliper. The new evergreen plant type tables remove the cross-reference to the shade tree table for determining minimum root ball diameter.
 

Recognition of certain containers

The 2014 edition recognizes containers that are now generally accepted in the nursery trade designed to manipulate root growth by root pruning and root training. Also, these containers may be manufactured with materials other than plastic (e.g., fabric, similar to in-ground fabric bags), such that the fabric container and a well-developed root system work together to hold the ball shape and protect the integrity of the root system during handling – even though the fabric “container” standing alone is not a “rigid” structure.

The 2014 edition eliminates the requirement from the 2004 edition that “the container shall be sufficiently rigid to hold the ball shape and protect the root mass during shipping.” The revised version also adds the following text (includes 2004 recognition of “treated” containers): “It is recognized that containers that encourage or manipulate root growth, such as the use of holes or fabric aeration to prune roots, coatings to prevent roots from reaching the sides of the container, or container shape to train roots to go in a certain direction, are acceptable in the trade.”

For more: Warren Quinn, The Quinn Management Group, LLC; warren@tqmgrp.com.