Laserfiche WebLink
Above ground standing biomass of herbaceous species (production) was <br />determined as the mean dry weight of all species at all plots within each <br />inventory area, and expressed in gm/m2 and lbs/acre. Shr~ and tree density <br />values were computed as the mean number of plants per lOm and per acre for <br />all species. <br />Sample adequacy for all data was computed following Snedecor and <br />Cochran, 1967 as <br />n min = t2s2/(dx)2 <br />where: <br />n min = the minimum number of observations needed <br />t = the distribution value for a given confidence level <br />(i.e., 1.282 for the 80% confidence level for <br />shrublands) <br />s2 = the variance estimate for preliminary vegetation <br />sampling <br />d = the level of accuracy desired for the estimate of the <br />mean (i.e. 10%) <br />x = the sample mean <br />2.9 Livestock Carrying Capacity <br />. Livestock carrying capacity of each vegetation type was determined by <br />considering the nutritional requirements of cattle and sheep (Stoddard et al, <br />1975) according to the following assumptions. A cow and calf (cattle animal <br />unit) consumes 900 pounds of air dry forage per month and a ewe and lamb <br />(sheep animal unit) consumes 150 pounds of air dry forage per month. The <br />conversion of oven dry weight to air dry weight is 1.11. The ideal <br />utilization factor for forage grazing is 50 percent. The livestock carrying <br />capacity was determined by the following: <br />LCC = (1.11 x FA x .5)/FC <br />Where: <br />LCC = Livestock Carrying Capacity (AUM per acre) <br />FA =Forage Available (oven dry lbs/acre) <br />FC =Forage Consumption Requirement <br />(900 lbs for cattle AUht; <br />150 lbs for sheep AUM) <br />• <br />3 <br />