Laserfiche WebLink
2. If an optical point bar is used, intercepts will be recorded based on the item <br />intercepted by fine crosshairs situated within each of 10 optical scopes located at 10- <br />centimeter intervals. <br />3. If a 10-point frame is used, sharpened pins will be used to determine intercepts at <br />10-centimeter intervals. Care will be taken to NOT record "side touches" on the <br />pins as this will result in a significant overestimation error. <br />The following sampling rules should apply during data collection. Intercepts will be <br />recorded for the first (typically highest) current annual (alive during the current growing <br />season) plant part intercepted without regard to underlying intercepts or attachment to a <br />living base except when multiple strata are present. In this circumstance, multiple live <br />hits may be recorded, but only one hit per stratum with the second live hit being recorded <br />separately and not used to calculate total ground cover. Otherwise, the intercept will be <br />litter, rock or bare soil. Rock intercepts are based on a particle size of 2 mm or larger <br />(MRCS definition), otherwise it would be classified as bare soil. To distinguish between <br />current year senescent plant material and litter (including standing dead), the following <br />rule should apply: 1) if the material is gray or faded tan it should be considered litter; and <br />2) if the material is bright yellow or beige it should be considered current annual (alive) <br />and recorded by species. On occasion, experience with non-conforming taxa may <br />override this rule. <br />When using laser or optic instruments during windy field conditions, the observer should <br />consistently utilize one of the following techniques for determining a hit: 1) record the <br />first item focused upon that is intercepted by the narrow laser beam or cross-hair; 2) wait <br />a few moments and record the item intercepted for the longest time, or 3) block the wind <br />and record the intercept. When using a pin frame, the observer must wait for the wind to <br />subside. <br />With regard to gaps in the overstory, the point-intercept procedure naturally corrects for <br />overestimations created by 2-dimensional areal (quadrat) or 1-dimensional linear (line- <br />intercept) techniques. In this regard, the 0-dimensional point is extended along a line-of- <br />sight until it "intercepts" something that is then recorded. Frequently points simply pass <br />through overstory gaps until a lower plant part, litter, rock or bare soil is encountered. <br />Regardless of instrument, a total of 100 intercepts per transect will be recorded resulting <br />in 1 percent cover per intercept. This methodology and instrumentation (excepting the <br />10-point frame) facilitates the collection of the most unbiased, repeatable, precise, and <br />cost-effective ground cover data possible. Identification and nomenclature of plant <br />species should follow Weber and Wittman (1996) Colorado Flora: Western Slope or <br />newer text. <br />Determination of Production <br />Where production samples are to be collected (7+ year-old units or Bond Release units) <br />current annual herbaceous production will be collected from a 1/2 m2 quadrat frame <br />placed one meter and 90° to the right (clockwise) of the ground cover transect to facilitate <br />4.15-30 Revision Date: 3/14/08 <br />Revision No.: TR-72