New Guideline Specifications for Nursery Tree Quality from the Urban Tree Foundation

Specifications and details are required elements of the design and construction process – they’re what ensure the proper components get built in the right place and to the right standards. Yet for trees, all too often the details and specifications don’t actually depict conditions that are optimal for growth. ANSI A300 established standard tree planting language and encourages professionals to write specifications, but there are few that are current, recognized, and available. Uneven foundational knowledge of how to properly detail and specify trees and improve their growing conditions is one reason urban trees may struggle to thrive.

To address this issue, Brian Kempf and Tyson Carroll of the Urban Tree Foundation, Dr. Ed Gilman with the University of Florida, and Jim Urban, FASLA, recently developed a comprehensive set of new, improved, peer-reviewed details and specifications for urban trees to be used by landscape architects, engineers, architects, contractors, urban foresters, arborists, municipalities, and state agencies.

The specifications (available in Word and PDF) cover the following topics:

The details (available in AutoCAD and PDF) cover the following topics:

I spoke to Brian Kempf, director of the Urban Tree Foundation, and Tyson Carroll, a landscape architect and project manager, about how this project came about, what improvements these details and specifications make, and what they hope and expect for how they will be used. Our conversation has been edited and condensed.

When did the effort to write these details and specifications start, and how long did they take to develop?

The idea of creating new details and specifications had been discussed for a while, because we’ve noticed for some time that landscape construction specifications and details are often out of date. For too long there has been a disconnect between the different professions in our industry around standards for tree quality, planting, and care.

The actual effort to go after the grant, get the money, and put it together to create a viable tool began around 2011. CalFire Urban and Community Forestry funded the effort. That’s when we got organized and assembled a team. It was a major undertaking that took about a year and a half going from concept to launch. We’re in the middle of the launch process now.

What are the most pressing issues you observe needing to be addressed?

Everything! From how the plant is grown and what it should look like, to how you prep the soil, create the planting space, and more – but mainly it comes down to the quality of the tree, site preparation, and planning.

Specifications need to establish the criteria and requirements for the project. For plant quality, this is an essential first step for success. We often see landscape architects call out “Z60,” which references the size of the plant in relation to the size of the root ball, but has nothing to do with quality. Essentially, there was no clear accountability, and in many cases people weren’t even aware whether their chosen specification was adequate.

The details, because they are pictures, tell a story in a way that the specifications can’t. They are meant to define some of the most common problems with trees and help people understand what they mean and how to evaluate and accept or reject the stock based on these essential criteria. Our goal for the details was to call out the critical elements found in the specifications to know about quality trees, site preparation, and and planting practices in a way that is easily understandable by designers and installers.

Who were your peer reviewers?

Our peer reviewers included consulting arborists, arborists, municipalities, growers, landscape contractors, and landscape architects. We tried to get reviewers from across the industry. It was important to us to obtain input from a variety of professionals who have different perspectives from across the country.

You’re located in California. Are these details and specs geared toward people working in the Western half of the U.S.?

We worked hard to make sure the details and specifications address the various issues that affect people in different parts of the country, but there’s no way to cover 100 percent of scenarios. What we’re providing is the base, the bones, to allow them to change whatever may be necessary for their site or project. We particularly want to get these out to smaller firms and communities with fewer staff and resources so that they can use these for their development standards.

Is it fair to call these documents best management practices (BMPs)?

I wouldn’t call these BMPs; I would call them peer-reviewed and say they are in accordance with industry BMPs. We pulled the very best information that we could from both researchers and practitioners. It took a year and a half and was incredibly intensive. It was not easy! It required a lot of writing, a lot of drawing, a lot of editing, and a lot of discussion.

How do you hope these details and specifications will be used?

We want these to be used by everyone – and we want to make it as easy as possible. Specs and details are not cheap to develop so we’ve seen that firms are sometimes reluctant to redo them. We made these free to use and modify without asking permission or giving any credit because we want to remove any barrier to people incorporating them into their projects.

In addition to delivering peer-reviewed, research-drive tools in people’s hands, we hope this will encourage people from across our industry to use these as a basis for their projects and modify them to confirm to local conditions. I’ve worked with many wonderful people over the years but still see a lot of finger pointing. This is a tree-driven effort, yes, but our feeling is that a complete landscape package is essential because these issues are all interrelated. Our hope is that people will be willing to embrace the tools if they see that.

All the specifications and details are open source, free, and can be edited by the user to fit the specifics of the site and the project goals. You are free to use them in projects without charge and without credit to the Urban Tree Foundation or any of the project team members. The authors write, “Although we encourage modification to fit your specific site and project needs, make your changes only after carefully considering all the pertinent variables at the planting site.”

Funding for this project was provided by the California Department of Forestry (CDF), Urban Forestry Program.

You can download the new specifications and details here.

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