ANSI A300 Pruning Standard Changes in Public Review Period
ANSI A300 Part 1, Pruning, is being revised, and changes are in the works. What are the implications for arborists?
By Geoff Kempter
The revision of the ANSI A300 pruning standard brings important changes that will affect how arborists and other landscape professionals write their work specifications. Improvements in the flow should make the whole process easier. Changes also include removal of “Pruning Methods” and a greater emphasis on specifying pruning objectives. The separate “Utility Pruning “section will be gone, and for the first time, the concept of “Pruning Systems” will be introduced. Though these changes are significant, the end result will be a document that is easier to use, and should help practitioners improve their pruning specifications, and their service to clients.
Here’s how you can participate:
The public review period for the revision of A300 Part 1 Pruning and A300 Part 9 Tree Risk Assessment standards is in effect from August 19, 2016 to October 3, 2016.
Review drafts and download copies here
There are two methods for providing input and comments:
1. Send your comments to your member representative. Your representative will use your comments to develop comments or suggestions for your organization. If you chose this method, a formal response from the A300 committee will not be provided.
2. Send your comments directly to the A300 secretary, Bob Rouse. The committee will review your comments at the next committee meeting on October 4-6, 2016 and provide an official response to each comment. Email comments to Bob at rrouse@tcia.org
Here are some thing you should know before providing comments:
Improved flow
The revised document’s content has been re-ordered to better reflect the natural flow of work and the structure of a good specification. Earlier versions placed several pages of definitions at the beginning, and the “Objectives” section was in the middle. A separate section for utility pruning was orphaned at the end.
The new version recommends specifying objectives first, followed by how the objectives are to be accomplished (see Figure 1), and lastly any other necessary details. The large “Definitions” section has been moved to the end of the document.
Figure 1: Comparison of structure of old and new versions of ANSI A300 Part 1, Pruning.
New “Pruning Specifications” section
A stated purpose of A300 is to guide the development of written specifications, whether for the simple removal of one branch or for the maintenance of a million trees along a utility system. This section provides information on what should be included in most pruning specifications.
This section also provides guidance about specifying how much to prune. Earlier versions recommended removing no more than 25 percent of the crown or foliage in an annual growing season. However, there was no restriction on removing 25 percent in consecutive growing seasons. The standard also stated that the pruning amount “shall be adjusted according to species, age, health and site.” Despite this explicit guidance, to many, 25 percent had become a de facto threshold, not to be exceeded regardless of other circumstances. The revision recognizes that far more or less that the 25 percent guideline may be necessary and emphasizes consideration of objectives, species, size, age, condition and site when specifying how much to prune.
Removal of “Pruning Methods (types)”
The 2008/2014 version required one or more pruning “methods” to be specified, including “Clean,” “Raise,” “Reduce” and “Thin.” These terms were often ambiguous or misunderstood, or confused with objectives. For example, as a specification “clean the crown” lacks specifics (what, how much, where, what size, etc.). As an objective, its purpose is not clear – is the crown being cleaned to reduce risk, promote health, improve appearance? Objectives need to be clearly stated in specifications to ensure that tree owners and arborists clearly understand what is to be done before work starts. “Clean” has been removed from the standard, though it remains a defined term.
Likewise, “thinning” has also been removed (though it also remains a defined term) due partly to the ambiguity of the term. While “thinning” is widely understood to refer to the process of pruning to reduce the density of live branches, the term “thinning cut” was often described as the removal of a branch to a parent (as opposed to a “reduction cut,” which removes a branch to a smaller lateral). This implied that the process of “thinning” must be performed with “thinning cuts.” However, most arborists would agree that a combination of reduction cuts and cuts to parent stems should be used if thinning is necessary. This contradiction, along with the fact that the process of “thinning” is often prescribed even when not necessary, is why the term was removed.
Rather than specifying a “method,” the revision places emphasis on specifying one or more pruning objectives, and what is required to accomplish those objectives. So returning to our “clean the crown” example, an alternative specification could include clearly stated objectives e.g. “reduce risk and improve tree health,” a pruning system and a description of what to prune, including the sizes, types and locations of pruning cuts. Lastly, other details such as clearance distances, debris disposal methods and other information can be added as needed.
Looking ahead
As ANSI A300 has expanded in scope, so too has the amount of work necessary to maintain the standard. Currently the full committee meets just twice each year, with much of the work done by subcommittees behind the scenes. ASC A300 needs the ongoing engagement of the many industry associations, universities, corporations, government agencies and, most importantly, the volunteers who donate their time and expertise in creating these standards that continue to drive improvements in the profession of arboriculture.
Geoff Kempter is the chair of the ASC A300 Pruning Revision Subgroup. He has served as the Asplundh representative on the ASC A300 Committee since 1996.