Treesearch

Two cultural treatments were evaluated over a 6-year post-treatment period to determine their effect on regeneration of native woodlands in southwestern North Dakota. Cultural treatments included livestock exclusion and the combination of felling and removal of low-vigor trees and transplanting of woody plants. Shrub density varied by species when grazed and ungrazed treatments were compared. American elm (Ulmus americana) increased on grazed areas. Thinning and removal of decadent tree stems stimulated sprout regeneration of green ash (Fraxinum pennsylvanica) and American elm, and...

Ten-year survival and growth of seedlings from 77 parent trees from throughout the Black Hills were compared, using a cluster-analysis technique. Five clusters were identified that account for most of the variability in survival and growth of the open-pollinated families. One cluster, containing 6 families, exhibited exceptional survival and growth. Another, containing 12 families, exhibited poor survival and growth. The performance of families in these two groups appears to be related to location and elevation of parent trees.

Prescribed burning created a more favorable seedbed by exposing mineral soil and increasing soil moisture, resulting in a twenty-fold increase in the number of seeds germinating on burned compared to unburned sites.

Five equation systems are described which can be used to estimate upper stem diameter, total individual tree cubic-foot volume, and merchantable cubic-foot volumes to any merchantability imit (expressed in terms of diameter or height), both inside and outside bark. The equations provide consistent results since they are mathematically related and are fit using stem analysis data from plantation-grown red and loblolly pine. Comparisons are made to determine which equation system provides the best overall fit to a set of validation data for each species. Results indicate that a system based...

A unique selection of antelope bitterbrush (Purshia tridentata [Pursh] DC) recently became the first accession of this valuable western shrub species to be released for commercial seed collection and production. Chosen for its productivity, palatability, winter leafiness, cover value, and seedling vigor, 'Lassen' antelope bitterbrush is a useful shrub for wildlife and livestock ranges, conservation plantings, and reclamation projects on adapted sites in the Intermountain and Pacific Northwest regions.

Genetic differentiation of 64 populations from central Idaho was studied in field, greenhouse and laboratory tests. Analyses of variables reflecting growth potential, phenology, morphology, cold hardiness and periodicity of shoot elongation revealed population differentiation for a variety of traits. Regression models related as much as 61 percent of the variance among populations to the elevation and geographic location of the seed source. Clinical patterns of adaptive variation provide the basis for developing seed transfer guidelines that will control maladaptation in reforestation. In...

Seedling populations were grown and compared in common environments. Statistical analyses detected genetic differences between populations for numerous traits reflecting growth potential and periodicity of shoot elongation. Multiple regression models described an adaptive landscape in which populations from low elevations have a high growth potential while those from high elevations have a low growth potential. Patterns of genetic variation reflect adaptation to a growing season of variable length. Adaptive landscapes are used to construct guidelines for limiting seed transfer in artificial...

Tests hypotheses for mule deer population increases between the early 1930's and mid-1960's. Concludes that livestock grazing and absence of fire converted vast areas of grasses and forbs to woody plants favored by mule deer. Mule deer populations, therefore, irrupted between 1930 and 1965 and have since experienced a decline as plant succession moves toward shrub senescence and trees. Habitat management alternatives are discussed.

Necrotic reactions in branch or main stems of western white pine (Pinus monticola Dougl.) caused by infection by the blister rust fungus (Cronartium ribicola J. C. Fisch. ex Rabenh.) are a major mechanism of resistance. Overall, 26 percent of the seedlings eliminated the fungus via this defense system. Heritability based upon crossing family groups averaged 33 percent for three sets of crossing groups. Heritability based upon individuals averaged 4 percent. The largest genetic advance (selected population compared to the original population before introduction of blister rust) could be...

I examined trends in bird species richness and overall bird abundance in riparian habitats among elevations varying from 6740 ft. to 9800 ft. in southeastern Wyoming. Bird species diversity ranged from a low of three bird species and 23 pairs in subalpine shrub willow habitat to a maximum of 21 species and 101 pairs in lowland cottonwood habitat. Bird communities were less diverse at higher elevations probably because of the reduced vegetational complexity and increased environmental severity at high elevations. Few bird species found in subalpine riparian habitats contained unique (but...