Nights are cool throughout the year at the TTR. For all these reasons, restoration of disturbed land, although difficult because of low rainfall, would be somewhat easier to achieve at the TTR than in the Mojave Desert. The revegetation experiences at the Palanquin study site on Pahute Mesa on the NTS (Wallace et al., 1973) are of some relevance to the conditions at the TTR. Both sites are in the Great Basin Desert. Both have less than 20 cm of rainfall per year on the average. Both are shrublands, although with somewhat different vegetation (Wallace et al., 1972; Leavitt, 1974; Rhoads, 1974; Rhoads and Mullen, 1974). After the native ground cover of the Palanquin close-in fallout pattern had been killed by radiation from a nuclear test, the area rapidly became a grassland. Measurements taken 4 years after this event showed very little grass in the undisturbed areas compared to a grass cover of 28% in an area in which the shrubs had been killed by the radiation (Wallace et al., 1972). The grasses were typically Sitanton jubatum and Hilaria jamesit, although Oryzopsis hymenotdes and Poa sandbergii also were abundant. Important considerations arise from these effects. For one, when the shrubs were killed, they could no longer compete with seedlings for soil moisture. Such plants then survive. However, since few grass seeds were available in the area at the time the vegetation was killed, it took about 4 years to build up a sufficient supply of grass seed to complete the process of grassland development. This is typical when shrub competition minimizes seed production of nonshrub species. It is expected then that any revegetation process can be hastened by planting grass seed into the disturbed areas resulting from cleanup procedures. Soil conditions differ markedly at Pahute Mesa and on the TTR, the more produc- tive soils being at Pahute Mesa. In addition, the radiation kill at Pahute Mesa did not involve any soil disturbance such as removal of topsoil containing seeds and soil organic matter. Any cleanup operation which removes topsoil containing the majority of the soil organic matter will result in far more drastic effects than the radiation kill at Pahute Mesa. The results then at the Palanquin site could not be expected to be completely duplicated at the TTR without careful land manipulation. The limiting factors for reestablishment of vegetation for disturbed areas will be the same in any desert. These are: first, low soil moisture; second, unfavorable soil structure resulting from very low soil organic matter; third, harsh chemical soil environment related to salinization and high CaC03; fourth, the invasion of disturbed areas by unwanted annual plant species such as Salsola; and fifth, animal activity which destroys many new seedlings. These five factors result not only in difficulty of plant reestablishment, but also in soil instability ending in wind and water erosion. Principles and practices for land restoration and revegetation which may be useful at the TTR and elsewhere have been outlined previously (Wallace and Romney, 1974). It is generally considered that revegetation is extremely difficult to achieve with less than 25 cm annual precipitation (Bleak et al., 1965). The 13 cm at TTR falls well below this level. Since the TTR is in a cattle-grazing area, revegetation and land manipulation should be done with future grazing in mind. Initially, however, the restored area should be 67