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A total of 90 bushes (75 percent) sprouted in the old burn and 56 (50 percent) sprouted in the area not previously burned. The subsequent survival of the antelope bitterbrush was fairly poor. Only 108 of the 146 plants that sprouted were alive the next year. Mortality was particularly high among plants that sprouted after burning in the May and June treatments. The loss of antelope bitterbrush sprouts the second or third season following a fire has been a problem in many areas. Fred Wagstaff studied succession in an important mule deer wintering area in Wasatch County, Utah, four years after it had burned in a large fire in 1979.38 There had been considerable sprouting, but in a burned-unburned comparison, the browse production in the burned area was practically nil because of the small size of the plants and their coverage by even a slight snowfall. Remember, too, that Nord stressed how attractive sprouting browse in burns is to animals and the damage that concentrations of animals can do to postburn succession. In 1994 John Cook and his colleagues burned high-elevation (ca. 8,000 feet) mountain brush communities and studied the response of the vegetation.39 This modern study has additional significance because it was conducted in a geographical area where little has been written about Purshia species. The antelope bitterbrush was entirely eliminated by the fire in some locations, while in others as many as 66 percent of the plants survived. It is not clear if the surviving plants were regenerated from sprouts or were plants that escaped the fires. Within three years the surviving plants had sufficiently increased browse production to compensate for the lost vegetation. The authors found that the crude protein content of herbaceous vegetation in the burned areas was markedly higher than in paired unburned controls. Increased protein content may be significant in attracting concentrations of grazers and browsers to the vegetation in burned areas and therefore influencing succession. At another extreme of the distribution of antelope bitterbrush, W. W. Fraas et al. studied the effects of prescribed burning on an antelope bitterbrush– mountain big sagebrush/bluebunch wheatgrass community in the Steep Mountain area near Butte, Montana.40 They sampled burned and unburned communities eight years after the prescribed burn. Antelope bitterbrush density did not differ between burned and unburned communities, but cover, flower production, and seed production were found to be less on the burned site. James Blaisdell began his research on antelope bitterbrush during the early 1950s on the Upper Snake River Plains in response to complaints from wildlife managers that prescribed burning was destroying mule deer habitat. By the 1970s, prescribed burning was gaining acceptance among the managers of ponderosa pine woodlands in the Pacific Northwest. Robert E. Martin, then with the usda, Forest Service, and Charles H. Driver, a professor of forestry at the University of Washington, were among the major advocates of prescribed burn188 Purshia ing in woodland management, but they were concerned that criticism from wildlife managers was limiting the application of prescribed burning. To allay such criticism they prepared a lengthy review of the factors affecting antelope bitterbrush reestablishment following fire.41 The review was divided into sections on sprouting and seedling establishment. Under sprouting they discussed the following points: 11. Genetic variability and morphology 12. Phenological condition 13. Plant age 14. Competition 15. Soil type 16. Soil moisture 17. Burning conditions 18. History 19. Fuel load 10. Browsing pressure The genetic variability section summarizes studies of the variability of Purshia populations, including Wagle’s lengthy dissertation from the University of California at Berkeley.42 But neither the cited studies nor subsequent work has established that sprouting is a heritable characteristic in Purshia populations. Without citation, Martin and Driver reported that sprouting of antelope bitterbrush can occur from 3 to 13 months after fire. Martin and Driver also reported that antelope bitterbrush can develop lignotubers —swellings of the main stem at or just below the soil surface—that consistently sprout. They hedged their bet, however, by including a disclaimer that it was possible that lignotubers occurred only in central Washington, where Driver et al. had found them.43 Martin and Driver had a hard time with the phenology and sprouting sections . They reviewed the applicable literature indicating that total available carbohydrate reserves decrease with bud breaking, growth, and flowering (see Chapter 4). The problem is that some researchers (e.g., Blaisdell and Mueggler) have found that the best sprouting occurs...

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