Analysis of the Urban Forest Structure of Morgantown, WV: Role of Remote Sensing in Sampling

Sandhya Mohan, Department of Biology, West Virginia University, smohan@mix.wvu.edu

Jonathan R. Cumming, Department of Biology, West Virginia University, jcumming@wvu.edu

Urban forests, defined as assemblages of trees and associated vegetation in an urban setting, have structural and functional components that provide distinct ecosystem benefits to the city residents including storm water retention and pollution abatement. Information about urban forest structure, such as species composition, tree density and tree health is a prerequisite for planning, designing and managing city vegetation on local and regional scales. Small cities such as Morgantown, WV, (population < 50000), tend to be under-represented in urban forest assessments but constitute approximately 70% of the U.S. cities and therefore need to be studied. Remote sensing is a useful tool to assess rapidly changing land use that plays a major role in altering urban forest structure and associated function. Land use/ land cover classes in the city of Morgantown and adjoining areas was delineated by manual digitization using WV DOQQs (1:12000, NAPP, 1996) for Morgantown North. One hundred and twenty plots (0.4 ha) were randomly located within these classes and each plot assessed for percent tree cover, ground cover type, tree species diversity, abundance and basal area /ha. Trees were measured for DBH, height, and crown dieback. The most abundant tree species in Morgantown are Acer saccharum, Prunus serotina, Robinia pseudoacacia and Acer rubrum, which reflect the composition of the native forests of the area. Residential areas had the highest species diversity, though ornamental species were most abundant. Forest and urban vegetation corridor classes had the highest values for tree cover, basal area and number of trees per hectare. Invasive and pioneer species such as Ailanthus altissima and Lonicera sp were more abundant in commercial and in institutional areas. For assessing change in land use, current data for the city coverage was acquired by ADAR System 1000 on a Piper Apache airplane (at 10,000 ft). The georectified and mosiacked images are then compared with DOQQs for changes within land use classes. Information on change in urban forest structure is important for small cities like Morgantown to aid in invasive species control, tree planting decisions and monitoring vulnerable species for signs of decline.