Laserfiche WebLink
Sample adequacy requirements for effected area cover data were <br />calculated using the OSM formula <br />s=t= <br />nmin = ldz~ <br />where nmin = the minimum adequate number of cover Transacts <br />s= = sample variance <br />t= = a designated t-statistic 10.84 for a one-tailed test with <br />BO% confidence) <br />d = desired limits of detection 10.1 or 10%1 <br />x = sample mean <br />2.5.2 Collection and Analysis of Shrub and Tree Data <br />Shrub heights end densities and tree heights, densities, and <br />diameters at breast height IDBHI were measured at each cover transact <br />location. In some vegetation types additional sample sites were randomly <br />located to meet sample adequacy requirements. <br />• The crown height of the first two individuals of each shrub <br />species with a canopy overlapping the transact line were measured to the <br />nearest centimeter. Likewise, the height end DBH of the first two indi- <br />viduals of each tree species with canopies overlapping the trensect line <br />were measuretl. DBH's were recorded to the nearest centimeter and heights <br />were estimated to the nearest meter. Accuracy of tree height estimates was <br />improved through the occasional use of en Abney inclinometer, tope measure, <br />and geometry calculations. When the appropriate number of tree or shrub <br />species was not present along the trensect for measurement, those individual <br />tree end shrub species nearest the trensect line were selected and measured. <br />Quadrats were used to collect density data. A rectangular <br />quadrat 50 meters by 5 meters was established along the cover trensect. Tne <br />number of mature (greater then 1.3 meters in height) trees rooted within the <br />quadrat was recorded by species. Quadrat size and shape varied for shrub <br />tlensity estimation. A circular quadrat with a 1.25 meter radius 14.9 m2 <br />in areal was centered at the end of the line trensect in the Rabbitbrush <br />Shrubland and shrubs counted by species. A square quadrat 5 meters by <br />5 meters located et the end of the line trensect was used in the Juniper <br />Woodland effected and reference areas. <br />Shrub end tree tlata were analyzed statistically using the same <br />OSM formula as for cover with density used for the mean. <br />• <br />-4- <br />