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from about 11 feet to about 17 feet from the tree trunk produced 2.53 percent total herbaceous cover. The fourth zone extended from a distance of about 17 and outward and yielded 4.28 percent total herbaceous cover. The total herbaceous forage production from these four zones was reported to be 0, 293, 190 and 475 pounds of air -dry forage per acre. Blue grama roots in northern Arizona were reported by Jameson (1966) to average 0.9 g per 1/4 ft3 at the edge of the edge of a juniper tree, 8.8 g per 1/4 ft3 five feet beyond the canopy edge and 13.1 g perl /4 ft3 25 feet from the canopy edge and beyond. He stated that Juniper and Blue Grama roots are concentrated at different soil depths. Water extracts of the foliage of One -seed Juniper reduced the growth of wheat radicles 79 percent and that similar reductions were found in the growth of Blue Grama. In field studies from three locations, dominated by One -seed Juniper and Pinyon Pine, tree litter was found to be the most important factor influencing the growth of Blue Grama. It was found that both of these tree species contributed about the identical amount of litter. Working Pinyon- Juniper woodland in northern Arizona, Jameson (1966, 1967 and 197 1) reported that herbage production sites with no tree density averaged about 600 pounds of air -dry forage per acre while when canopy cover reached about 10 percent production was reduced to less than 200 pounds of air -dry forage per acre with less than 100 pounds of air -dry forage per acre on transects with 60 percent canopy cover and less than 50 pounds of air -dry forage on transects with 80 percent or more canopy cover. Laboratory studies performed on Utah Juniper extract on the germination of six range species resulted in Blue Grama, Created Wheatgrass and Sideoats Grama showing the greatest reductions in seed germination. The foliage litter also negatively affects the soils' properties and in laboratory studies, soil collected adjacent to juniper roots or ground up roots mixed with potting soil inhibited leaf growth of Blue Grama and Sideoats Grama. Alligator juniper showed the greatest negative effect, Utah Juniper the least and One -seed Juniper midway. Working in south central New Mexico on One -seed Juniper, Schott and Pieper (1985) reported that since the European settlement of the western United States, there has been a significant increase in the extent of Pinyon- Juniper woodlands and concomitant decrease in the production of understory species. This decline was "attributed to shading, water interception, litter accumulation and allelopathy." Their study involved an analysis of the understory vegetation beneath One -seed Juniper. Three locations beneath the tree were studied, immediately adjacent to the trunk, half the distance from the trunk to the edge of the canopy and at the edge of the canopy. They reported that total grass cover averaged 3.95 percent of the middle zone, 18.2 percent for the middle zone and 33.25 for the outer zone. Statistically significant differences in total plant cover were found for all zones. Three of the four grass species encountered all decreased in cover as they grew closer to the tree trunk. The parameters which were found to statistically correlated with grass growth were the degree of canopy closure, tree trunk diameter, and litter which were all negatively correlated with grass growth. Several factors were found to be related to the distribution of the grass cover, including shading, litter fall and litter accumulation, the latter two which are allelopathic 31