The vegetation distribution data used in the model were derived using the South Florida portion of the Florida Department of Transportation vegetation map, which is a satellite image at the 30m scale. Vegetation data is represented at both the 100m and 500m scales, which are aggregations of the 30m satellite image [FDG+94].
Each 100m and 500m grid cell contains two quality classes of forage: high quality and medium quality. High quality forage has a higher caloric value, but is lower in quantity. Medium quality forage, on the other hand, has a lower caloric value and is higher in quantity. In addition to high and medium quality forage, there is unlimited low quality forage of the least caloric value. This class of forage can satisfy only about 80% of a deer's daily energy requirements [CGF+95].
On the first day of the simulation, initial quantities of high and medium quality forage are assigned to each 100m grid cell based on its vegetation type and average water level for that year. These quantities are updated at the 100m scale daily, weekly, or monthly for growth effects, depending on a user-selected option. Depending on the time of year, forage amounts either increase or decrease due to seasonal vegetative growth and deterioration. After computing available quantities at the 100m scale, 500m forage quantities are computed by averaging values in the 25 constituent 100m cells. In addition to seasonal growth effects, forage amounts in specific 100m and 500m grid cells are updated daily after each deer grazes.