Transplanting and a Deeper Look at “Fall Hazards”

B&B trees on truck Matthew Stephens
B&B trees dug properly—i.e., when dormant. Photo by Matthew Stephens

by NYC Parks Director of Street Tree Planting Matthew Stephens and Taking Root Editor Michelle Sutton

We coauthored this story questioning commonly held beliefs about “fall hazards,” mostly as it applies to B&B trees, but we also discuss the interaction of the fall season with other production methods, like bare root. The section, “The Five Branches of Transplanting Success,” should be of interest to anyone planting trees, period!  With the help of Nina Bassuk and others, we tried to break down the complex interactions at work with transplanting. This article originally ran in Arbor Age (Fall 2015).  

The nursery industry is reluctant to dig certain species of trees in the fall, yet the “fall hazards” lists can vary significantly among nurseries. Also varying is the experience of nursery customers, including city foresters who plant hundreds or thousands of trees each year. In addition to digging season, there are other interacting factors at play in the fall planting picture.

A More Nuanced Look
Cornell Urban Horticulture Institute Director and street tree expert Dr. Nina Bassuk says, “Those fall hazards lists are generalizations. Typically the trees that appear on those lists are trees that are more difficult to transplant, period. In spring they don’t become easy to transplant; they’re just observed to be easier in the spring than in the fall.”

Tree Pittsburgh Director of Urban Forestry Matthew Erb has overseen the planting of more than 25,000 trees (mostly B&B) since 2008. “I’m sure if you look hard enough, you will find nearly every species on someone’s fall hazard list,” he says.

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Cornell Urban Hort Institute: Interesting Research Continues Apace

The Council’s longtime Board member and beloved speaker, Nina Bassuk, gives us an update on three areas of research underway at UHI. Dr. Bassuk will be the plenary speaker for the NYSUFC Conference this July. (Register now for best rate!) 

UHI researchers are attempting to fast-track propagation of alkaline-tolerant oaks that should come onto the market in the next five to ten years.
UHI researchers are attempting to fast-track propagation of alkaline-tolerant oaks that should come onto the market in the next five to ten years. Photos Courtesy UHI.

New Oaks for Tough Sites 
Dr. Nina Bassuk founded and directs Cornell’s Urban Horticulture Institute (UHI) and conducts applied research in the areas of plant improvement, transplanting technologies, and soil remediation.  “We think of everything we do in terms of potential practical value to the field,” she says.

For example, owing to hybridizing work UHI has been doing since the early 1990s, some oak introductions will be coming onto the market in the next five to ten years that could be game-changers: a whole series of oaks—not just English and bur oak—that can tolerate a pH of 8.0! That means oaks with foliage that stays green in the alkaline soil conditions prevalent in urban settings (and we are increasingly recognizing that in terms of plant stress, “urban” conditions are everywhere—not just in cities.)

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