Cornell Urban Horticulture Institute Director Nina Bassuk and Dept of Horticulture Post-doctoral Associate Fred Cowett recently published a paper called “Street Tree Diversity in Three Northeastern U.S. States” in Arboriculture & Urban Forestry, the scientific journal of the International Society of Arboriculture. What follows is the abstract, and the full paper is here.
Abstract. Street tree diversity is widely viewed as a key component in the resilience of street tree populations to pests, diseases, and climate change. Assessment of street tree diversity is considered integral to sustainable street tree management and preservation of the ecosystem services and social benefits that street trees provide. This paper assesses street tree diversity in three northeastern U.S. states— New Jersey, New York, and Pennsylvania—by analyzing municipal street tree inventory data stratified by the 2012 USDA Plant Hardiness Zones. Despite the lesson learned from the historical devastation of overplanted American elms (Ulmus americana) by Dutch elm disease, and awareness of the contemporary threats posed to ashes (Fraxinus spp.) by the emerald ash borer (Agrilus planipennis) and to maples (Acer spp.), and other tree genera by the Asian longhorned beetle (Anoplophora glabripennis), results presented here indicate a current concentration of street trees among a relatively small number of species and genera, and in particular the dominance of maples as street trees. Results also show a positive relationship between street tree diversity and warmer average minimum winter temperatures. Consequently, there is a clear need in all three states for greater species and genus diversity in statewide and municipal street tree populations. However, meaningful impediments exist to increasing street tree diversity, especially in the short term.
Some blog posts resonate long past their original publication date date. Transplanting and a Deeper Look at “Fall Hazards” was one of the top five posts in 2015 and was the second most viewed post in 2016. Former NYC Director of Street Tree Planting Matt Stephens and Taking Root Editor Michelle Sutton coauthored this story questioning commonly held beliefs about “fall hazards,” mostly as it applies to B&B trees, but they also discuss the interaction of the fall season with other production methods, like bare root. Nina Bassuk helped craft the section called “The Five Branches of Transplanting Success,” which should be of interest to anyone planting trees.
Kristy King and NYC Forest Restoration: Dreaming Big for the City’s Natural Areas Many readers wanted to learn about the work of the NYC Natural Resources Group, which manages 5,000 acres of forested natural areas across the five boroughs of NYC, and about Director of Forest Restoration Kristy King. Her dream for NYC: “… that all forested areas are dominated by native species and that invasive species have been managed to the point that natural forest regeneration is occurring and that the public holistically values the natural resources in their area.”
NYSDEC Urban Forestry Intern Jennifer Kotary: Get to Know Her! Many blog readers were keen to know about this dynamic up-and-comer. “My internship research involved in-depth exploration of what communities are doing to protect and build green infrastructure across the state. Via Mary’s [Kramarchyk] assigned projects, I was able to produce tangible evidence that there is quite the statewide collective will to plant and nurture an expanding canopy as well as many career and volunteer opportunities to do so.”
SMA’s 2016 Urban Tree of the Year: Musashino Zelkova generated a lot of buzz. ‘Musashino’ has been a successful and popular street tree for many more years in Japan, proving itself useful as a narrow, upright form of zelkova. It can tolerate drought and heat and is pH adaptable and pollution tolerant. See a list of all the past SMA Urban Trees of the Year here.
Gary Raffel: Get to Know Him! Gary has served the Council in a variety of capacities, including as a board member. “I started Dynamic Tree Systems in 2002, offering general tree care service as well as Plant Health Care and Integrated Pest Management programs. I later wanted to find a niche in the industry and purchased a Tree Radar Unit at a time when there were only three of us in the U.S. and eleven people in the world using the equipment. A few years later I became the company’s international trainer, such that when a new unit was sold I would fly to the particular client and spend a week training them on their new equipment (I still do that, in addition to Dynamic Tree Systems).”
Drs. Susan Day and Nina Bassuk have collaborated on a variety of research projects in the urban forest, with a special focus on soil remediation. Susan Day is an associate professor in the Virginia Tech Departments of Forest Resources & Environmental Conservation and Horticulture, and longtime Council stalwart Nina Bassuk directs the Urban Horticulture Institute at Cornell.
Here, Susan Day summarizes her findings after ten years of researching Soil Profile Rebuilding (SPR), a technique that the urban forestry community will be hearing about! See also this post from 2014 about Nina Bassuk’s related soil amendment research.
Soil Profile Rebuilding: An Alternative to Soil Replacement
by Susan Downing Day
Urban foresters and their allies know poor soils can lead to an endless cycle of dieback and tree replacement. Even if trees do establish, growth can be underwhelming and tree health disappointing. Increasingly, project managers have been turning to soil replacement, where existing soils are excavated and removed and replaced with “recycled” or blended soils. These soils present their own challenges, however. For example, many imported blends rely on high sand contents to improve drainage, resulting in low water-holding capacity and drought stress for unirrigated plantings. Resulting sharp transitions in soil texture introduce the possibility of creating a “bath tub” effect in situations where it is impossible to replace all the soil and new soils are confined to the immediate vicinity of individual trees.
There is an alternative to soil replacement that is especially appropriate where there are extended open soil (unpaved) areas such as in street medians—soil rehabilitation. Soil rehabilitation can help restore important ecosystem functions such as stormwater transmission and vegetation support to existing native soils.
October 9-15, 2016, cyclists will experience a week of unforgettable scenery, cycling and camaraderie as the Tour des Trees rolls through the Piedmont region of North and South Carolina, starting and ending in Charlotte, NC.
Tree plantings and community engagement are hallmarks of every Tour, and Professor Elwood Pricklethorn (aka Toronto arborist and veteran Tour cyclist Warren Hoselton) provides educational programs for young audiences along the way. The Tour also adds new trees to the growing urban forest planted by its cyclists.
Since 1992, the Tour des Trees has grown to become the largest fundraiser for tree research and education in the world. In 2015, it generated over $340,000 that will be used to support a variety of research projects and educational programs for budding tree care professionals.
Four years ago, I embarked upon my first journey with the Stihl Tour des Trees to benefit the TREE (Tree Research and Education Endowment) Fund. I could not have known how much of an impact that one week would have on my life. I remember how hard that first tour was—I never knew my knees could hurt that bad from just pedaling a bicycle. I am happy to say that through three bike tours, my fellow bike riders became among my dearest friends. We have encouraged and learned from each other. The biggest lesson I have learned is that it’s okay to ask for help—and sometimes the nicest people will come along and help you without you even asking.
Above: Allen Nichols doing a chestnut planting demonstration with home schoolers in Plattsburgh, NY.
I became aware of the American chestnut (Castanea dentata) when my father pointed out the remains of dead trees to me when I was just a boy. I was aware of the resprouts that keep coming up and then dying back from the blight. Then, when I was a teenager I witnessed the death of all the great American elms on our farm, which gave me a vision of what must have happened when the Chestnut blight killed all the chestnuts 50+ years earlier. I think that the devastation to ash trees today by Emerald Ash Borer and ash yellows and decline is giving the next generation a glimpse of what has happened in the past.
Our Council blog was viewed more than 14,000 times in 2015! Here are the top five posts:
Sumana Serchan: Get to Know Her! Sumana Serchan is an urban forester with NYC Parks and Recreation. Sumana has a master’s degree in Environmental Management from the Yale School of Forestry and Environmental Studies and a bachelor’s degree in Natural Resources/Conservation from the Rubenstein School of Environment and Natural Resources (University of Vermont). She grew up in Kathmandu City, Nepal.
Transplanting and a Deeper Look at “Fall Hazards” NYC Director of Street Tree Planting Matt Stephens and Taking Root Editor Michelle Sutton coauthored this story questioning commonly held beliefs about “fall hazards,” mostly as it applies to B&B trees, but they also discuss the interaction of the fall season with other production methods, like bare root. Nina Bassuk helped craft the section called “The Five Branches of Transplanting Success,” which should be of interest to anyone planting trees.
A New Method for Streamlining Tree Selection in NYCCouncil President and NYC Parks Senior Forester David Moore shares how the City streamlined its system for making tree species selections for 25,000 street tree plantings a year using an ingenious categorization of “biotopes.” A municipality of any size can use this article to think strategically about their tree selection process.
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.
At the 2015 ReLeaf Conference, you will have the opportunity to go behind the scenes of the SUNY ESF Chestnut Research and Restoration Project. Why is this research so critical? Why is bread mold key to the restoration of the American chestnut (Castanea dentata)? Watch these videos, and just try not to become infected with enthusiasm for this effort!
On ReLeaf Thursday, take a tour with Dr. Chuck Maynard of the laboratory and greenhouse where this groundbreaking research takes place. On Friday, hear the keynote talk from Maynard and Dr. Bill Powell, codirectors of the American Chestnut Research and Restoration Project, about restoring the American Chestnut.
Not yet familiar with NUCFAC? The 1990 U.S. Farm Bill created NUCFAC to advise the Secretary of Agriculture on matters relating to the protection, planting, and care of trees and forests in our nation’s cities and communities. NUCFAC brings together U&CF professionals to strategize the health and future preservation of America’s urban forests. Working together, the Council brings that a full spectrum of views into a consistent vision that is the foundation for a practical national policy on urban forestry.
One of the summer’s most widely circulated urban forestry-related stories was about the TD Bank Group’s evaluation of the economic value of Toronto’s urban forest. TD Bank Group, which acts as a think tank as well as an advisory group of economists and has a full-time environmental economist on staff, is chaired by Senior Vice President and Chief Economist Craig Alexander.
In a great interview with Alexander on the Alliance for Community Trees (ACTrees) website, he said that his group found that for every dollar of maintenance, the trees are returning between $1.35 and $3.20 (a 220% return) in benefits. Alexander says, “It’s a good investment. We aren’t including things we can’t measure like the intangibles of being able to go to a park and enjoy the trees. This is a low ball number because you can’t measure everything.”
It’s thrilling for City of Toronto urban foresters and indeed urban foresters everywhere to get this kind of affirmation from economists from the second largest bank in Canada (eighth largest bank in the U.S.). In their capacity as a policy think tank, Alexander said his group of economists does research on the environment and that this is the first of their reports on “natural capital.” He says, “Economics measures GDP, but there is a lot that doesn’t get measured, including the value of the environment.”
In the ACTrees article, Alexander says, “The challenge we have on public policy and environmental issues is at the end of the day, you have to have a dollars and sense argument on your investment. This kind of data also really helps politicians and government officials to make decisions. Everyone is facing fiscal constraints… we need to economically appreciate what trees do. In the aggregate the numbers are really impressive.” This is something urban foresters have known for a long time, but coming from TB Bank’s Chief Economist, it will greatly add to this awareness among the populace.
You can read the full TD Bank Group report here.
You can read a great profile of Toronto’s urban forestry program here, starting on p 10 in the July/Aug 2011 issue of City Trees.