. Planning single-span skylines. Logging, Skyline. appears most profitable or that has the highest cost. Skyline yarding costs should not be compared directly with yarding costs of other systems since yarding distances for skylines may be greater. Instead, total logging costs (, all costs from stump to delivery point) should be used in a comparison. LAYOUT OF CUTTING UNITS Once the comprehensive logging plan has been completed, layout of cutting units may be started. This phase of work is done by use of aerial photographs, topo- graphic maps, and timber-type maps. Aerial photos in ster
. Planning single-span skylines. Logging, Skyline. appears most profitable or that has the highest cost. Skyline yarding costs should not be compared directly with yarding costs of other systems since yarding distances for skylines may be greater. Instead, total logging costs (, all costs from stump to delivery point) should be used in a comparison. LAYOUT OF CUTTING UNITS Once the comprehensive logging plan has been completed, layout of cutting units may be started. This phase of work is done by use of aerial photographs, topo- graphic maps, and timber-type maps. Aerial photos in stereopairs may be used to identify preliminary landings, anchor points, and spar trees. Anchors may be located within proposed cutting units, but more often it is desirable to locate them outside a cutting unit to improve deflect- ion or to take advantage of larger anchor stumps. Detail identified on the photos may be transferred to a topographic map for use in laying out cutting units and skyline roads. Good-quality skyline road profiles may be plotted from topographic maps having a scale of 1 inch = 400 feet and a contour interval of 20 feet. The planner should be aware that accuracy of topo- graphic maps in mountainous terrain may be questionable and suitable only for pre- liminary work pending onsite confirma- tion. Accurate data on timber volume per acre and log size are needed for estimat- ing yarding and rigging costs. Timber-type maps should also be superimposed on the topographic maps to identify more clearly where skyline roads may be located. Figure 2 illustrates location of skyline roads in a forest area which has been laid out for single spans. M I PROPOSED ACCESS ROAD CUTTING UNIT BOUNDARY LANDING ANCHOR POINT SKYLINE ROAD e x. Figure 2.—Rock Mountain skyline logging Please note that these images are extracted from scanned page images that may have been digitally enhanced for readability - coloration and appearance of these illustrations may not perfectly re
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