Height or Height Class- The height of each tree species is recorded in inches. A height class is recorded for shrubs: .5 is given for shrubs less than one foot in height, 1 is given for shrubs between the height of 1 and 2 feet, 2 is given for shrubs between the height of 2 and 4 feet, and so on. Height measurements will be taken in subsequent years and used to help estimate the time it will take various species to reach a free-to-grow status.