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Killing of the above-ground portion of the plant will stimulate production <br />• of root suckers and crown sprouts, which results in thickening of open <br />stands and merging of scattered stands into continuous thickets. Con- <br />versely, stands that age without disturbance tend to thin out into scat- <br />tered clumps. Brown (1958) also found the oak shrub much more dense on <br />steep slopes than on gradual slopes. <br />The dense shrub cover in the WSC permit area restricts the abundance <br />of understory plants. The ground thickly covered with oak litter and few <br />grasses and forbs are present. In the oak shrub openings herbaceous growth <br />is sparse, although a few forbs (e.g., aster, goldenrod, beggars tick, and <br />sweet clover) and some grasses (e.g., inland bluegrass, wheatgrass, <br />junegrass and bromegrasses) provide some herbaceous cover. Rocky outcrops <br />often cause openings in the shrub overstory, and these sites have little or <br />no herbaceous vegetation. <br />The shrub overstory is itself variable. Some areas have stands of <br />pure Gambel oak; elsewhere the oak is accompanied by a number of other <br />shrubs including Oregon grape, Woods rose, snowberry, serviceberry and <br />sometimes chokecherry. Shrub canopy cover is generally high, often <br />approaching 100 percent, except in the infrequent openings where there is <br />little or no shrub cover. <br />The character of the oak shrub vegetation results in extremely <br />variable data when herbaceous cover and productivity and shrub density are <br />sampled. Approximately 45 percent of the quadrats sampled during the 1980 <br />vegetation study (see Appendix XVII) had no herbaceous vegetation. Instead <br />.7 <br />2.04-44 <br />