Treesearch

Eight-year tree growth of western larch (Larix occidentalis) and Douglas-fir (Pseudotsuga menziesii) was measured following prescribed underburning on burned and control plots in western Montana. Western larch on bun.ed plots had reduced radial growth in the first year following fire but increased growth in the next 7 years. Douglas-fir had similar growth on burned and unburned plots. Growth was not reduced by low levels of crown scorch or cambial injury. Stand basal area growth was less on burned plots due to high fire-caused mortality.

Mortality was determined in a stand of Douglas-fir 8 years after 20 plots were treated with light surface fires. Logistic regression was used to model long-term mortality as functions of morphological variables measured shortly after burning. Independent variables were diameter at breast height, height of needle scorch, percentage of the prefire crown volume scorched, season of burn, and the number of quadrants with dead cambium at 1.4 m bole height. Mortality increased with increasing scorch height, percent crown scorch, and dead cambium. It decreased with larger diameter. The best...

Describes the climate of the largest designated wilderness in the conterminous United States. Contains numerous maps, graphs, and tables. Shows annual patterns and 10-day details during the fire season. Includes both average values and frequency distributions. Examines relationship of climatic averages to topography, persistence of weather, and climatic trends.

Small mammals and vegetation were sampled over two years in Rocky Mountain juniper woodlands and adjacent grasslands in South Dakota. Juniper woodlands provided specialized habitat for two woodland species, white-footed mice and bushy-tailed woodrats, and attracted a number of species generally associated with grasslands.

Carrying capacities for cattle competing with black-tailed prairie dogs (Cynomys ludovicianus) were estimated by a linear programming technique for management of cool-season grasses in western South Dakota. Forage utilization was allowed to range from 20% to 80%. Under management for cool-season grasses (western wheatgrass (Agropyron smithii); needlegrasses (Stipa spp.)), stocking rates of cows ranged from 43 to 214 per hectare over a 6-month grazing season, and cow-calf stocking rates ranged from-43 to 214 per hectare over a 6-month grazing season, and cow-calf stocking rates ranged from...

Diets of greater prairie chickens on the Sheyenne National Grassland of North Dakota were examined. During the winter months agricultural crops (primarily corn) were the predominant food items. Green vegetation was consumed in greater quantities as spring progressed. Dandelion flowers and alfalfa/sweetclover were the major vegetative food items through the summer. Both juvenile and adults selected diets high in digestible protein obtained through consumption of arthropods and some plants.

This paper describes a method for trapping prairie grouse hens on display grounds. The basic principle of the trap is a drift fence which funnels visiting hens into traps. The trap has been used successfully in at least 6 states and 2 provinces and on 4 species of prairie grouse. This method is less expensive and less disruptive than rocket or cannon nets.

To predict prairie dog establishment in areas adjacent to a colony we sampled: (1) VISIBILITY through the vegetation using a target, (2) POPULATION DENSITY at the colony edge, (3) DISTANCE from the edge to the potential site of settlement, and (4) % FORB COVER. Step-wise regression analysis indicated that establishment of prairie dogs in adjacent prairie was most likely to occur when an area was near a densely populated colony edge with high visibility through the vegetation.

Prairie chickens (Tympanuchus cupido pinnatus) were first censused on the Sheyenne Grasslands in 1961. The population was extremely low in the 1960's, gradually increased in the 1970's, and reached a peak of 410 in 1980. Sufficient evidence exists to link the increase in numbers of prairie chickens on the grasslands from 1961 through 1987 to changes in land management, primarily the introduction of ratational grazing pratices and prescribed burning of meadows.

Twenty radio-tagged prairie-chickens (6 cocks, 14 hens) were followed during the winter of 1984-85 on the Sheyenne National Grasslands in North Dakota. A total of 3,945 (2,879 day and 1,066 night) locations were obtained from 9 December to 15 March. Winter survival was high at 58.8%. Mean winter home range was 8.4 km2 and slightly larger for hens than cocks (8.8 km2 size vs 7.7 km2). Mean winter to spring movements were 4.4 km for cocks and 6.4 km for hens. All locations were within 6700 m of a known booming ground; 64% were within 2400 m with a mean of 2078 + 980 m. Cocks remained closer...