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Amherst, MA, United States

Shermana A.R.,60 Holdsworth Way | Kanea B.,60 Holdsworth Way | Autioc W.A.,05 Paige Laboratory | Harrisd J.R.,90 West Campus Dr. | Ryan H.D.P.,60 Holdsworth Way
Urban Forestry and Urban Greening | Year: 2016

Slow growth following transplanting is characteristic of the establishment period, which has been studied for many years. Most of this work, however, has been conducted on trees transplanted in nurseries or favorable growing sites. In urban areas, many trees are transplanted into more challenging growing conditions, and very few studies have investigated establishment period of such trees. We analyzed ten years of transplanting records for the metropolitan Boston, MA, USA area to determine the establishment period of three species commonly planted as street trees {hedge maple [Acer campestre L.], London planetree [Platanus x acerifolia (Ait.) Willd.], and red oak [Quercus rubra L.]}. Using piecewise linear regression, we determined the “break point,” the intersection of two lines fitted to a scatter plot of caliper versus years after transplanting. The break point indicates the number of years after transplanting at which growth rate increases—the establishment period. We also analyzed whether site factors affected stem caliper. Establishment period varied among species: 2.1 years, 4.0 years, and 5.9 years for red oak, London planetree, and hedge maple, respectively. Site factors variably affected stem caliper of different species. Stem caliper of London planetree and red oak increased with greater sidewalk cut-out area. Tree grates in sidewalk cut-outs adversely affected stem caliper of London planetree. Our results can help practitioners manage street trees in the northeastern United States, but more work on trees transplanted in urban areas is necessary to understand the initial post-transplant growth of street trees. © 2016 Elsevier GmbH

Kane B.,60 Holdsworth Way | Warren P.S.,60 Holdsworth Way | Lerman S.B.,60 Holdsworth Way | Lerman S.B.,U.S. Department of Agriculture
Urban Forestry and Urban Greening | Year: 2015

Trees in towns and cities provide habitat for wildlife. In particular, cavity-nesting birds nest in the dead and decayed stems and branches of these trees. The same dead and decayed stems and branches also have a greater likelihood of failure, which, in some circumstances, increases risk. We examined 1760 trees in Baltimore, MD, USA and western MA, USA, assessing tree risk and, for a sub-sample, noting the presence of cavity nests excavated by birds. In Baltimore, most trees were in areas of frequent use and had no visible defects. In western MA, most trees were in areas of infrequent use and 70% had visible defects. The most common defect in both locations was dead branches and stubs between 10 and 51. cm in diameter. Trees with a cavity nest had a greater likelihood of failure than trees without a cavity nest. Our data provide an overview of tree risk assessment and mitigation, a baseline understanding of risk parameters for common street trees in the Northeast and Mid-Atlantic regions of the United States, and insight into whether a balance can be struck between tree risk and provision of wildlife habitat. © 2015 Elsevier GmbH.

Reiland M.,60 Holdsworth Way | Kane B.,60 Holdsworth Way | Modarres-Sadeghi Y.,60 Governors Drive | Ryan H.D.P.,60 Holdsworth Way
Urban Forestry and Urban Greening | Year: 2015

In the United States, cabling is a common arboricultural practice intended to reduce the likelihood of failure of weakly attached or overextended branches, yet no studies have investigated whether this is true. We tested ten red oaks with and without (i) steel support cables and (ii) leaves using a conventional pull and release test. From acceleration time histories of freely swaying trees, we determined their natural frequency and damping ratio. Red oaks with cables had greater natural frequencies than trees without them because the cable increased trees' stiffness. Red oaks had greater natural frequencies when they were leafless, since the overall mass of the tree without leaves was smaller. Red oaks had greater damping ratios when they were in-leaf-presumably because of aerodynamic drag, but installing a cable did not affect the damping ratio. The latter finding suggests that the cable only affected trees' stiffness. Practitioners can use the findings to better understand the implications of installing support cables in trees, but additional work is needed to consider related variables such as the tension and height at which cables are installed. © 2015 Elsevier GmbH.

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