 Assessing Urban Ecosystems
Data Needs for Sample Inventory Projects
The data needs of UFORE depend to a certain extent upon the nature of the output desired -- i.e., what forest functions or values are to be quantified. See the Manual for details.
Field data inputs:
All Projects must contain field data inputs. In addition, if sampling is conducted, the following variables are required:
- Study area boundaries and size
- Land use categories and sizes (required if study area is stratified)
- Number of plots in each land use strata
UFORE Plots
The plot size and number of plots needed for a UFORE project are not fixed, although UFORE plots are usually .1 acre in size (circle with 37.2 foot radius).
The number of plots needed depends on the accuracy needed. Typically 200 plots will produce about a 10% standard error for the total number of trees. In the past, smaller cities have used 30 plots and larger cities such as New York and Baltimore have used approximately 200 plots.
A UFORE project typically begins with digital aerial photographs and land use maps of the study area, which are usually available for individual cities from local agencies. If these maps and photos are not locally available, the can be obtained from the USGS for free or at low-cost. The digital map is used in selection of field plot locations; aerial photographs aid field crews in determining the location of the plots. Where available, digital versions of aerial photographs can greatly simplify and speed up the sampling process. The i-Tree Sample Inventory Generator helps to automate this process.
After field plots are located on aerial photographs, whether electronically or manually, the plot locations are typically transferred to a street map of the area for ease of navigation for field crews. Where field plots were located on digital, geo-referenced photographs, plot locations can also be identified by their unique latitude and longitude. This allows the use of the geographic positioning system (GPS) units to locate the plots in the field.
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Weather and pollutant concentration inputs
In addition to field data inputs, and depending on outputs desired, location specific weather and air pollution inputs are required. These data are available for the United States for the year 2000 at no cost from the USDA Forest Service office in Syracuse, NY (support).
Weather data
Hourly weather data are necessary to analyze:
Air pollution data
Hourly pollution concentration data are required to analyze:
- air pollution removal by the urban forest
- relative ranking of species effects on air quality
Twice daily sounding measurements are needed to calculate percent air quality improvement due to pollution removal. Available from the Forest Service office in Syracuse for some areas or from NOAA, see the Manual.
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