Treesearch

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...

Guidelines are provided to help forest managers and silviculturists develop even- and/or uneven-aged cutting practices needed to convert old-growth and mixed ponderosa pine forests in the Front Range into managed stands for a variety of resource needs. Guidelines consider stand conditions, and insect and disease susceptibility. Cutting practices are designed to integrate maintained water quality, improved wildlife habitat, and enhanced opportunities for recreation and scenic viewing, with providing wood products.

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...

Conifer establishment following regeneration treatments can be predicted in the grand fir-cedar-hemlock ecosystem of the northern Rocky Mountains. Alternative treatments can be evaluated by a model that represents regeneration establishment and early development. This model is designed to be used with the Intermountain Forest and Range Experiment Station's Prognosis Model (Stage 1973). Mathematical equations representing most harvest and site preparation methods common in the northern Rocky Mountains predict the probability of stocking, trees per acre, species composition, and tree heights...

Cao's compatible, segmented polynomial taper equation (Q. V. Cao, H. E. Burkhart, and T. A. Max. For. Sci. 26: 71-80. 1980) is fitted to a large loblolly pine data set from the southeastern United States. Equations are presented that predict diameter at a given height, height to a given top diameter, and volume below a given position on the main stem. All estimates are inside bark. A condition is given that forces the Cao model to be exactly compatible with any total main stem volume equation. An exact volume estimation formula is derived. Twelve benchmarks, which represent realistic...

Describes a model for predicting moisture content of fine fuels for use with the BEHAVE fire behavior and fuel modeling system. The model is intended to meet the need for more accurate predictions of fine fuel moisture, particularly in northern conifer stands and on days following rain. The model is based on the Canadian Fine Fuel Moisture Code (FFMC), modified to account for solar heating of fuels and to predict diurnal trends in fine fuel moisture. The model may be initiated without extensive data on prior weather. When compared to the FFMC and the fire behavior officers' procedures, the...

Three alternatives using digital thematic mapper (TM), analog TM, and a combination of either digital or analog TM data with low altitude photography are discussed for level I and level II land use/land cover classes for a proposed national inventory. Digital TM data should prove satisfactory for estimating acreage in level I classes, although estimates of precision may be unreliable. Either the digital or the analog TH combined with low-altitude photography (LAP) are expected to yield satisfactory estimates for most level I and level II classes. Reliable estimates of precision can be...

Discusses fire as an ecological factor for forest habitat types occurring in central Idaho. Identifies "Fire Groups" of habitat types based on fire's role in forest succession. Considerations for fire management are suggested.