The Rutgers Urban Forestry Program is a partner in several graduate program and post-doctoral research projects housed within the departments of Ecology, Evolution, & Natural Resources, Environmental Science, Plant Biology, and Landscape Architecture.
A selection of research publications from the Urban Forestry Program are listed below.
Ryan J. Schmidt, Brianna Casario, Pam Zipse, Jason C. Grabosky
Poster is linked in the title, formal technical document to follow.
Jason Grabosky
In an increasingly urban world society, there is a need to provide fit habitats for urban dwellers. Toward that end, the development of methods for urban tree and whole urban canopy management is foundational for the provision of a quality environment. Life cycle curves are a convenient method which can be developed for specific or generalized service value provisions. Furthermore, such curves can be developed on common design forms and tree typologies within a regional species palette. A series of studies in New Jersey and Florida inform the idea to suggest the feasibility and merit of such an approach for urban tree management planning.
Grabosky, J. (2017). Life cycle curves linked to root zone colonization space for urban trees as a foundation to meet urban forest design and longevity goals. Acta Hortic. 1189, 363-370
DOI: 10.17660/ActaHortic.2017.1189.70
Allyson B.Salisbury, Frank J. Gallagher, Joshua S. Caplan, Jason C. Grabosky
Improving our understanding of plant responses to elevated trace metal concentrations under field conditions will enhance restoration and urban greening practices in settings with contaminated soils. This study examined the effects of trace metal pollution on the leaf gas exchange rates of mature, field grown Betula populifolia Marsh. (gray birch) trees, additionally assessing whether elevated temperature and drought compounded the effects of trace metal contamination. The study compared B. populifolia growing in areas of comparatively high and low trace metal loads (HML and LML, respectively) within a former rail yard at Liberty State Park in Jersey City, New Jersey, USA. Gas exchange parameters were determined monthly from May through September in 2014 and 2015 using a portable photosynthesis system. The effects of drought and high temperature were assessed during a short heat wave in July 2015 and via a manipulative experiment, respectively. During a few of the measurement months, some parameters differed significantly between the LML and HML groups. However, when considered over the entire study period, no significant differences in biophysical parameters were observed between groups. The photosynthetic capacity of B. populifolia thus appears to be fairly robust across this site’s steep gradient of trace metal contamination. Nonetheless, leaf mass per unit area was significantly lower in the HML group, indicating that metal loads affected resource allocation within trees. Also, immediately following the heatwave in 2015, intrinsic water use efficiency declined significantly in the HML group, suggesting that extreme climatic conditions can have a disproportionate effect on the physiological performance of plants growing in metal contaminated soils.
Salisbury, A., F. Gallagher, J. Caplan, J. Grabosky. 2017. Maintenance of photosynthesis by Betula populifolia in metal contaminated soils. Science of the Total Environment; doi:10.1016/j.scitotenv.2017.12.279
Dr. Grabosky is currently working with several graduate students on a variety of research projects related to urban and community forestry.
If you are interested in pursuing graduate studies in Urban Forestry, contact Dr. Grabosky.
Landscape-Scale Evapotranspiration in the New Jersey Pinelands (YouTube link)
Bernard Isaacson, PhD, Ecology & Evolution
Forest evapotranspiration (ET) is the dominant term in water budgets over forests, so minor changes in ET have outsize impacts on the behavior of associated water resources. This research uses remote sensing inputs and DisALEXI model outputs to quantify the effect of generalized forest management actions, forest composition, forest density, and other disturbances on ET over the coastal plain pine forest of southern NJ. The water budget in this system is dominated by ET, and almost all precipitation not recycled into the atmosphere moves through the underlying unconsolidated sand and gravel aquifer. Results indicate that long-term changes to forest structure arising from reductions in disturbance cause considerable, and previously ignored, increases in ET. Disturbance-dependent ecosystems experiencing less-frequent disturbance may witness negative consequences for the stability of groundwater resources due to increased landscape-scale water use by vegetation. Regulatory and administrative conditions established to safeguard the forest resource from some of those disturbances may thus be counter-productive for ensuring robust water provisioning.
The Allometric Relationship of Tree Diameter and Crown Volume (Full Dissertation)
Richard Leopold, PhD, Ecology & Evolution
The objective of this study is to analyze the allometric relationship between the diameter at breast height (DBH) and crown volume. The question presented is: Does site type influence this relationship? The species selected for this study are Quercus rubra, Quercus palustris, Acer rubrum, Acer platinoids, Pyrus calleryana, Gleditsia triacanthos, Planatanus X acerifolia, Zelkova seratta,all species of Tilia spp, and Fraxinus spp. Four different site types have been identified, lawns, pits, small strips, and large strips. Lawns are classified as areas with non-limited root growth in all directions. Pits are growing areas that are limited in root growth in all directions, sidewalk cutouts. Strips are areas with non-limited growth in two directions 180 degrees from one another, areas between the street curb and the sidewalk. Furthermore, strips have been divided into large strips, greater than 4 feet up to 12 feet in the limiting directions, and small strips, less than or equal to 4 feet in the limiting direction.
The DBH is measured, recorded and a bright dot placed at the point of measure to provide a known height for image analysis. A high resolution digital photograph is then taken. The image is then processed using software called ImageJ. This software allows us to scale the pixels of the image to the known height of 4.5 feet based on the location of the dot placed on the tree. The following image measurements are taken, DBH, total tree height, crown height, and crown diameter at regular intervals of crown height. Volume of the crown is then calculated by way of analyzing each crown segment as a truncated cone (Cadori et al. 2016, Heger 1965).
Once the crown volumes have been calculated the allometric relationship for each species site combination will be performed. An analysis will be used to determine if there are significant differences in the allometric scaling relationship of DBH and crown volume between the different site types. Understanding how site type influences growth patterns can allow us to better employ the concept of the right tree for the right site. Furthermore, time and money can be saved by predicting multiple measurements while only having to take one measurement.