UHI Research Conclusions: Scoop & Dump Soil Remediation Strategy

In their recent paper in Urban Forestry and Urban Greening, “Long-Term Remediation of Compacted Urban Soils by Physical Fracturing and Incorporation of Compost,” study authors Miles Sax, Nina Bassuk, Harold van Es, and Don Rakow published their findings after twelve years of applied research. The technique, “Scoop & Dump Soil Remediation,” was introduced in a previous Council blog post about Urban Horticulture Institute research.

From the Urban Forestry and Urban Greening paper’s Abstract:

On the Cornell University campus a long-term study has measured the impacts of a soil remediation strategy on plant growth and soil quality using the Cornell Soil Health Test. The Scoop & Dump (S&D) process of soil remediation consists of physically fracturing compacted urban soils, incorporating large quantities (33% by volume) of compost with the use of a backhoe, and annually top dressing with mulch. This study was designed to investigate the impact of this remediation technique for the amelioration of compaction and degradation of soils in the urbanized environment.

From the Urban Forestry and Urban Greening paper’s Conclusion:

The authors found that the Scoop & Dump method of soil remediation showed improvement in soil quality indicators – bulk density, resistance, aggregate stability, potentially mineralizable nitrogen, active carbon and organic matter content – compared to unamended sites. Over a period of 12 years, soil quality indicators – bulk density, active carbon and potentially mineralizable nitrogen – improved over time showing long-term beneficial effects of using the Scoop & Dump Technique.

The application of the Scoop & Dump soil remediation strategy is an appropriate method for restoring soils damaged by heavy equipment, building construction and urbanization impacts. With minimal annual maintenance including the addition of shredded bark mulch, these improvements in soil quality are maintained or enhanced over time. This technique offers a practical, research-based tool for green industry professionals, arborists and landscape contractors and has a strong potential for improving soil quality using locally sourced materials and sustainable methods.

Citation:
Sax, M.S., Bassuk, N., van Es, H., Rakow, D., Long-Term Remediation of Compacted Urban Soils by Physical Fracturing and Incorporation of Compost, Urban Forestry and Urban Greening (2017),  http://dx.doi.org/10.1016/j.ufug.2017.03.023

Underutilized Trees for Urban Use: ‘Regal Prince’ Oak

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Foliage of Regal Prince oak ● Photo by itrees.com

Regal Prince is the trademark name for Quercus x warei ‘Long’, a narrow, upright hybrid of fastigiate English oak (Quercus robur f. fastigiata) and swamp white oak (Quercus bicolor). Its leaves are clearly intermediate in shape and are glossy and leathery like those of swamp white oak. In Ithaca, Nina Bassuk and Andy Hillman first planted Regal Prince in 2005, and the oaks have performed well there ever since.

Quercus bicolor x robur 'Regal Prince'
Regal Prince oaks alongside the main thoroughfare in Ithaca, New York. Photo by Nina Bassuk

“It’s a good tree for tight spaces—not a shade tree as such,” says Cornell Urban Horticulture Institute Director Bassuk. “It has the shape of the fastigiate English oak but is more tolerant of poor drainage and is mildew resistant, unlike Q. robur. It also tolerates a higher pH than does straight Q. bicolor. During last summer’s drought its foliage stayed green throughout so it appears both wet and dry tolerant (after establishment of course).”

Read more…

Street Tree Diversity in Three Northeastern U.S. States

IMG_8973Cornell 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.

New Guide to CU Structural Soil®

Cover of CU Soil guideRecently, the Cornell Urban Horticulture Institute, headed by Nina Bassuk, published a 57-page Comprehensive Guide to CU-Structural Soil.

This is THE publication to share with your municipality’s engineers and leadership, to show the why and how of CU-Structural Soil.

CU-Structural Soil®, also known as CU-Soil®, is a two-part system comprised of a rigid stone “lattice” that meets engineering requirements for a load-bearing paving base, and a quantity of uncompacted soil that supports tree root growth.

The first section of the Guide discusses the role of soil volume and how to calculate how much soil volume a tree needs.  No matter how well matched your tree species is to its site, limited soil volume is something few trees can abide, much less thrive in.

CU schematic
CU-Soil conceptual diagram

The Guide goes on to give the case for CU-Structural Soil  in particular, and answers FAQs like “How much CU-Soil will I need?”, “How do you plant trees in CU-Soil?”, “Can it be retrofitted for use under existing trees?”, and “How is irrigation and drainage handled?” It also explains how to obtain CU-Soil that meets quality control specifications. (This, by the way, is why CU-Soil is licensed—to ensure quality control. Otherwise, anyone could mix up rocks and soil and claim to be selling “CU-Soil.”)

Read more…

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.

Read more…

Bare Root & UHI Webinars Update

Thanks to Nina Bassuk’s research and extension efforts in bare root transplanting technology, tens of thousands of trees have been planted in New York and the greater Northeast that would otherwise not have been. In 2014 alone, 8800 bare root trees were purchased by 93 municipalities across 11 states from Schichtel’s Nursery in Western NY.

Bare root planting by volunteers in Utica. Photo by Roger B. Smith
Bare root planting by volunteers in Utica. Photo by Roger B. Smith

Schichtel’s Sales Manager Jim Kisker, who has partnered with Nina on bare root and other research since 1990, says the vast majority of the nursery’s bare root sales go to municipalities that are using her bare root technique. Kisker says, “When I listen to some of our municipal customers give presentations on the success they’re having with bare root, they’re up in the exceptional 93-96 % survival rate with the dip and bag method. We know it works, because the same municipalities come back every year. Some have been buying from us, with this method, for 10-15 years and in some cases, 20-plus years.”

NYS DEC Urban Forestry Program Manager Mary Kramarchyk says, “When learning about volunteer efforts across the state, I find it uplifting that so many local tree stewards already know about bare-root tree planting and that they find it much easier to do than balled and burlap trees.”

Read more…

Ithaca’s Urban Forest Master Plan: A Template for Other Munis

Ithaca UFMPLooking for a template as you craft or revise your community’s urban forest master plan (UFMP)? Ithaca once again leads the way. The newly revised document includes a master plan, tree inventory data, and arboricultural guidelines.

To borrow from the Pittsburgh UFMP, “An Urban Forest Master Plan is a road map, providing detailed information, recommendations, and resources needed to effectively and proactively manage and grow a city’s tree canopy. More importantly it provides a shared vision for the future of the urban forest to inspire and engage stakeholders in the care and protection of trees.”

Ithaca Shade Tree Advisory Committee Chair Nina Bassuk says, “Ithaca’s newly revised UFMP has components that many municipalities might be interested in, including specs for soil, soil volume, and nursery stock. It also has our tree care guidelines for site selection, tree selection, tree protection during construction, tree removal, and even our solar panel policy.” There are meticulously rendered tree planting details for varied circumstances including planting with CU-Structural Soil.

Nina says, “I would also like to point folks to our Community Forestry website, where resources include several management plans and ordinances that might be of interest, and advice on creating master plans.”

Read more…

Nina Bassuk Receives Frederick Law Olmsted Award from Arbor Day Foundation

RELEAF 255Last fall, the NYSUFC nominated beloved Cornell Urban Horticulture Institute (UHI) Director and longtime former Council President Nina Bassuk for the Arbor Day Foundation’s Frederick Law Olmsted Award. Current Council President Andy Hillman read the award description and said, “This appears to have been written for Nina!”

The Frederick Law Olmsted award recognizes an outstanding individual with a lifelong commitment to tree planting and conservation at a state or regional level. Further, it honors someone who: shows outstanding personal commitment over their career or lifetime for the betterment of the environment, mobilizes people in tree planting and care, makes unique or extraordinary contributions and commitment with regards to tree planting, landscape, conservation, education, or research, and serves as a role model and mentor to others.

The Council is so very pleased to announce that Nina received the Frederick Law Olmsted Award for 2015. Here is a video the Arbor Day Foundation made about Nina’s work that shows why she was the perfect candidate:

It was challenging to summarize Nina’s accomplishments in the three pages indicated by the award nomination guidelines. Here are some highlights:

  • Thanks to Dr. Bassuk’s research and extension efforts in bare root transplanting technology, tens of thousands of trees have been planted in New York and the greater Northeast that would otherwise not have been. In 2014 alone, 8800 bare root trees were purchased by 93 municipalities across 11 states from Schichtel’s Nursery in Western NY.
  • Dr. Bassuk has been the City of Ithaca Shade Tree Advisory Committee Chair since 1985, and she served on the Ithaca Parks Commission from 1991-2003. She served as the President of the NYS Urban Forestry Council from 1990-2001 and thereafter as a Board Member.

Read more…

Essential and Updated: The Cornell Woody Plants Database

Like me, you may have a dog-eared, well-worn copy of the Urban Horticulture Institute’s (UHI) Recommended Urban Trees: Site Assessment and Tree Selection for Stress Tolerance. Another fantastic resource for urban foresters and UF volunteers that has just been updated is the Cornell Woody Plants Database.

Screenshot 2014-12-01 06.11.09

Nina Bassuk says, “What makes the site unique is its focus on matching woody plants to site conditions, a feature sometimes lacking on other plant selection sites and a consideration that is sometimes lost in the design and plant selection process.” With its extensive image collection and cultural information, the site is also very useful for woody plant ID and study.

Each entry includes ultimate size and shape, USDA Hardiness Zone, light requirement, salt tolerance, moisture tolerance range, insect and disease considerations, and key ornamental features. Impressively, each entry has Nina voicing a short audio lesson that reinforces ornamental and ID features. Nina says this is a work in progress, as she is re-recording some of the entries for better audio quality.

Screenshot 2014-12-01 06.24.02

There is a Course Plant Walk section, which you can use to find a series of plant walks through the beautiful Cornell campus based on different criteria like species (e.g., oaks, maples, and rosaceous and flowering trees) or tolerances (e.g., dry site and wet site trees); click on Maps to see the walk route.

The database was originally the outgrowth of the year-long joint Horticulture/Landscape Architecture (LA) course, “Creating the Urban Eden,” taught by UHI Director Nina Bassuk and Dept of LA Chair Peter Trowbridge.

The site had modest beginnings as an “online textbook” circa 2000. The first version consisted of a FileMaker Pro database running on the Cornell network from a Mac under a desk in the main offices of the Department of Landscape Architecture. Since then, the site has grown significantly more sophisticated with three major revisions that added additional features and functionality. The most recent upgrade was supported by a SUNY Innovative Instruction Technology Grant in 2013.

Check out the Cornell Woody Plants Database!

A young 'Canada Red' Prunus virginiana
A young ‘Canada Red’ Prunus virginiana