Laserfiche WebLink
The balance of the conifer stands suitable for timber harvest were managed <br />as uneven aged. Again, the management is on a 120 -year rotation using <br />partial cutting or individual and group selection as the harvesting method. <br />The intention is to enter each sawtimber stand on a 30 -year entry cycle, <br />reducing the stand basal area to about 80 ft2 acre - ' at each entry. Depending <br />on the species, initial stand density varies up to 150 ft acre -'. Each year <br />1:30''' of the total area is thinned. <br />Spruce -Fir is the second most prevalent forest cover type in the North Platte <br />drainage, occupying about 25 percent of NFS land or 124,281 acres. ' <br />Approximately 4,143 acres of spruce -fir were thinned in 2001 with no <br />change in flow simulated. After 5 years, a total of 20,714 acres were <br />harvested and water yield increased from 15.7 to 16.0 inches. After 15 <br />years, 62,142 acres were harvested and flow increased to - 16.6 inches. In <br />total, the 0.9 inch increase in flow generated 9321 acre -feet of additional <br />water per year. We expect the long -term sustainable increase over the 120- <br />year rotation will average 14,000 acre -feet of water per year. This <br />represents a sizable increase from the 124,281 acres of spruce -fir forest. <br />Ponderosa pine occupies 14,179 acres of the Suitable for Timber Harvest ' <br />area. Ponderosa pine was also partially or selectively harvested and reduced <br />to a basal area of 80 ft2 acre'. In the year 2001, 473 acres were partially cut <br />with not impact on the base line water yield of 1.2 inches. By year 2005, <br />2363 acres of ponderosa pine were harvested with no simulated change in <br />flow. Although minor increases in flow might be expected, precipitation <br />was so limiting in this forest type that an increase in flow from timber <br />harvest was not simulated. ,. <br />Limber pine occupies only 118 acres of suitable area and hydrologic <br />simulation indicated we could increase water yield from current yield of 8.6 <br />inches in year 2000 to 9.5 inches in year 2015. Unfortunately, because of <br />limited area, this equates to an increase in total yield of less than 10 acre - <br />feet. , <br />Douglas fir occupies only 764 acres of the Suitable for Timber Harvest area. , <br />Like limber pine, the area is too limited to generate much of a change. After <br />15 years of partial cutting, water yield increased from 12.0 inches to 12.6 <br />inches and represents an increase of 38 acre -feet of water per year. Base <br />water yield for douglas fir as presented in table 11 is much higher than the <br />average water yield presented in table 8 for current conditions. This is a I <br />40 1 <br />