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Table 2.04.10 -7 <br />Mean Woody Plant Density (Stems /Acre) For Irrigated Pasture <br />Vegetation Type, New Horizon 2 Study Area, 1987' <br />Species <br />Stems /acre <br />Eleagnus angustifolia <br />0.5 <br />Juglans nigra <br />0.1 <br />Acer negundo <br />0.1 <br />Rosa nutkana <br />5.3 <br />Ulmus pumila <br />0_1 <br />Total <br />6.1 <br />' Tree densities reflect absolute counts of species occurring in the irrigated pasture type <br />using color aerial photography (stereo pairs, 1 = 500' scale). The total tree estimate for the <br />irrigated pasture type was 947 trees. Populus sargentii and Populus angustifolia occasionally <br />occurred along irrigated pasture borders containing ditches but were not included in the <br />densities. <br />2 Three Juglans nigra occurred in an irrigated pasture on the west side of the study area. <br />A total of 66 species were found to occur in the type (Attachment 2.04.10 -6, formerly Peabody <br />10 -1), with 21 of those species encountered in the cover sampling. Only 12 of these species <br />had relative cover values of 1 percent or greater. Of these 12 species, 8 were graminoids and <br />four were forbs. Though this represents a low level of diversity for native plant communities, <br />irrigated pastures that are in good condition and well managed should have a composition of <br />only a few species (Stewart 1973). <br />The general stocking rate for the irrigated pasture is approximately 1.2 AUM's /acre at a 70 <br />percent utilization rate. Since the production on these pastures can be sustained by irrigation, <br />this stocking rate should apply during the majority of the growing season. Ideally, the forage <br />should achieve a 4 -5 inch height in the spring and between pasture recovery periods before <br />grazing with allowance for a 4 -5 inch stubble height of vegetation remaining at the end of the <br />Revised September 2010 (PR 06) 2.04.10 -32 <br />