A glimpse into upcoming urban forestry research: Why have a tiny percentage of ash trees survived EAB? How can LIDAR be used to improve urban forest management? How do mycorrhizae help young trees access soil moisture? Why do seemingly healthy trees fail, unpredictably impacting power lines, and how can better failure models be developed?
TREE Fund raises these funds through its annual Tour des Trees epic bike ride. It’s not too late to register to ride in the 2019 Tour des Trees or to sponsor a rider. This year’s ride is in Kentucky and Tennessee, Sept 16-20.
“Backyards are very important,” says coauthor Dexter Locke. New insights from research on “Urban form, architecture, and the structure of front and backyard vegetation,” by Alessandro Ossolaa, Dexter Locke,
Brenda Linc, and Emily Minord in the Journal of Landscape and Urban Planning. 185 (2019) 141–157
Residential yards comprise most land and green space across cities. Despite yards being ubiquitous, little comprehensive information exists on how vegetation varies between front and backyards. This hinders our ability to optimize greening interventions on private urban land.
We devised an accurate GIS algorithm to locate and classify front and backyards within residential landscapes. By applying this method to the greater Boston area, we measured vegetation structure (i.e., canopy cover, height and volume) of front and backyards with LiDAR and multispectral imagery. We further investigated relationships between urban form, architectural style, socio-economics, and the structure of front and backyard vegetation across Boston’s residential landscapes.
On October 5th, 2018, Nina Bassuk led a tour of the new Sustainable Landscapes Trail on the Cornell campus after an opening ceremony in which, instead of ribbon-cutting, officials celebrated with a “downpour” of water onto the permeable asphalt of the Peterson parking lot, which is underlain by CU-Structural Soil and also features a large bioswale.
A number of the 20 sites along the Trail are associated with the Urban Horticulture Institute/Nina Bassuk, including chinkapin oaks (Quercus muehlenbergii) in CU Soil outside Stocking Hall, goldenrain trees (Koelreuteria paniculata) and silver lindens (Tilia tomentosa) in CU Soil outside Weill Hall, the Tower Road Bioswale, the Ag Quad Biodetention Basins, and the Mann Library Entrance SITES Accredited Garden. Many of these projects involved Nina Bassuk and Peter Trowbridge “Creating the Urban Eden” students in their implementation. For instance, the creation of the Rice Hall Bioswale involved students using the research-based “Scoop and Dump” technique described here.
For nearly 15 years, Nina Bassuk and her grad students at the Cornell Urban Horticulture Institute (UHI) have been developing hybrid oaks for exceptional tolerance of urban conditions (drought, alkaline soil, etc.) Bassuk now has 230 hybrid oaks of 2-3 inch caliper in her research fields. “I’d be happy for villages and cities in NY to plant them out so I can continue to evaluate them over time,” she says.
She is offering them to municipalities of any size in April of 2019. The cost would be $50 per tree to cover the B&B process. Communities could arrange for transportation or pick the trees up themselves. Bassuk says it would be preferable to have at least five trees go to any one community so she can efficiently evaluate them around the state.
If your community would like to plant at least five of these unique, new oak hybrids, please contact Nina Bassuk at firstname.lastname@example.org. Read on for more background about this fascinating research.
Nina Bassuk Reviews Applied Tree Biology by Andrew Hirons and Peter Thomas
Reprinted from the April 2018 Arborist News (Volume 27, Number 2).
The first thing to notice in this very excellent text is the title, Applied Tree Biology. This is not exactly an arboriculture manual or a tree biology textbook. It very deftly explores tree biology and then links it to the art and practice of arboriculture. Although the “applied” part of the text is not limited to managing trees in difficult environments, there is a definite subtext focusing on the trials of trees growing in managed or urban environments.
Ten comprehensive chapters address tree structure (wood, leaves, and roots), seed growth, water relations, carbon acquisition, nutrition, interactions with other organisms, and finally, environmental challenges. Each chapter is lavishly illustrated with graphics and pictures; it is difficult to find a page that does not have some illustrative feature. Given that this book is up-to-date and rather dense in content, the illustrations are very welcome.
In April 2018, the Cornell Urban Horticulture Institute team of Nina Bassuk, Bryan Denig, Yoshiki Harada, and Barbara Neal released an extensive report on the elms (including American elms) of the National Mall in Washington, D.C. The report details a study conducted at the request of the National Park Service to examine the current conditions of the trees and soils on the tree panels of the National Mall, and it includes a fascinating history of the landscape. Here are some highlights from the report.
The National Mall elm trees are an important planting in the monumental core, yet they face several challenges. The soils of the tree panels are very compacted, most likely due to the constant pedestrian use and the numerous large organized events that take place on the Mall. Unevenness in the size and distribution of the tree canopy has resulted from decades of mortality (often due to Dutch Elm Disease) and the planting of certain elm varieties with growth forms that are seen as incompatible with the planting as a whole.
From June 17–20, 2017, the research team conducted a tree inventory and collected soil data and samples for later analysis. In addition, in November 2017, ground penetrating radar done by Council member Gary Raffel was used to document root growth for seventeen of the trees. This report deals with the current tree and soil conditions, while management recommendations are in a separate report to be released in late 2018 or early 2019.
Whoa. Worms can cause a lot of problems, as we’ve been exploring on the blog with regard to the organic matter over-consumer, Asian jumping worm. A Michigan Tech study entitled “Evidence of damage from exotic invasive earthworm activity was highly correlated to sugar maple dieback in the Upper Great Lakes region” points to … just that. That is, the way in which earthworms (which, due to glacial scraping in the past, are not native in Michigan or in New York) are directly and indirectly contributing to or causing maple decline, which has affected urban forests as well as exurban ones.
Michigan Tech did a great summary of the research and here is the abstract for the study, published in the journal Biological Invasions. The lead author is Dr. Tara Bal, who wrote her dissertation about sugar maple decline in the Upper Great Lakes Region.
Sugar maple (Acer sacharrum Marsh.) in the western Upper Great Lakes region has recently been reported with increased crown dieback symptoms, prompting investigation of the dieback etiology across the region. Evaluation of sugar maple dieback from 2009 to 2012 across a 120 plot network in Upper Michigan, northern Wisconsin, and eastern Minnesota has indicated that forest floor disturbance impacts from exotic invasive earthworms was significantly related to maple dieback. Other plot level variables tested showed significant relationships among dieback and increased soil carbon, decreased soil manganese, and reduced herbaceous cover, each of which was also be correlated to earthworm activity. Relationships between possible causal factors and recent growth trends and seedling counts were also examined. Maple regeneration counts were not correlated with the amount of dieback. The recent mean radial increment was significantly correlated with various soil features and nutrients. This study presents significant evidence correlating sugar maple dieback in the western Upper Great Lakes region with earthworm activity, and highlights the need for considering the impacts of non-native earthworm on soil properties when assessing sugar maple health and productivity.
New NYSUFC Board Member Joseph Charap is the Director of Horticulture and Curator for Green-Wood in Brooklyn. He’s also a new dad—his son Benjamin was born on September 3rd. Charap and his Green-Wood colleagues are transforming the historic landscape of this cemetery into an urban arboretum/public garden and expanding the ways people utilize its many resources.
I am a native New Yorker and I grew up in Lower Manhattan. After earning a BA and an MA in English Literature, I began working in a schizophrenia research lab. In my limited free-time, I assisted a professional gardener working in residential gardens around the city. It was during this time that I really began to connect with trees and other plants.
Through this work and other projects, it became clear to me that horticulture was my calling, but that I needed to get professional training. After a chance meeting with New York Botanical Garden (NYBG) Vice President Francisca Coelho in 2013, I applied to and was accepted into NYBG’s School of Professional Horticulture. During my second year of the program, I held an internship at Green-Wood, and upon graduating, I was hired as Curator of Plant Collections. In January of 2017, I was made Director of Horticulture at Green-Wood.
Green-Wood Cemetery was founded in 1838 as one of the earliest “rural cemeteries.” It’s an accredited Level II Arboretum, occupying 478 acres in Brooklyn. We believe we will achieve Level III Accreditation within the next five years, as we continue to diversify our tree and shrub collection. [Level III arboreta have at least 500 species of woody plants, employ a collections curator, have substantial educational programming, collaborate with other arboreta, publicize their collections, and actively participate in tree science and conservation.]