Adams, Robert P., and Thomas A. Zanoni. 1979. The distribution, synonomy, and taxonomy of three junipers of southwestern United States and northern Mexico. Sout
Vasek, F.C. 1966. The distribution and taxonomy of three western junipers. Brittonia 18: 350-372.
Vatikus, M.R. and L.E. Eddleman, COMPOSITION AND PRODUCTIVITY OF A WESTERN JUNIPER UNDERSTORY AND ITS RESPONSE TO CANOPY REMOVAL, Proceedings Pinyon-Juniper Conference, Jan. 1987, p. 456-460.
Understory production was sampled in 1983 and 1984 by clipping small plots on a per tree basis. Areas with intact juniper canopies and areas from which juniper had been removed in 1982 served as treatment comparisons. Canopy removal resulted in species -specific productivity increases. Production increases were greatest beneath the canopy and least in the interspaces. Poa sandbergii did not respond to canopy removal, while other perennial grasses provided small, but variable production increases. Annual grasses and forbs contributed most to elevated productivity following juniper removal.
Vest, E.D., BIOTIC COMMUNITIES IN THE SALT LAKE DESERT, University of Utah, Institute of Environmental Resources Ecology and Epizoology Serial No. 73, Salt Lake City, UT., 1962.
Wagstaff, F.J., ECONOMICS OF MANAGING PINYON-JUNIPER LANDS FOR WOODLAND PRODUCTS, Proceedings Pinyon-Juniper Conference, Jan. 1987, p. 168-172.
Pinyon-juniper forests provide a broad array of economic products ranging from edible nuts and various wood products to recreational benefits and wildlife habitat. Utilization of the renewable woodland products provides basic employment, income and other benefits. Value of the standing crop on some of the more productive pinyon-juniper sites is several hundred dollars per acre based on just the value of domestic fuelwood. Although rotation may be long, the lack of viable alternative uses of the land and the strong demand for the woodland products means management and use of these forests make economic sense.
Wakely, L.A., CHANGING HABITAT CONDITIONS ON BIGHORN SHEEP RANGES IN COLORADO, Journal of Wildlife Management, vol. 51, 1987, p. 904-912.
Changes in habitat associated with the decline and extinction of 36 populations of rocky mountain bighorn sheep in Colorado were investigated using a mapping approach. Differences in habitat conditions were compared between: 1) 19 ranges currently occupied by bighorn sheep (in 1982) and 17 ranges no longer supporting sheep herds; 2) presently occupied vs. recently (ca. 1970) abandoned portions of 3 sheep ranges; and 3) habitat characteristics of the declining Beaver Creek herd in 1962 vs. 1977. Ranges supporting greater numbers of bighorn sheep had more high-visibility habitat, greater area dominated by grass and rock cover, more habitat on and near open escape terrain, and dense shrubland and forest resulted in fragmentation and reduced amounts of high-visibility habitat on and near open escape terrain on the Beaver Creek range. In the absence of fire or habitat management, vegetation succession has been a major cause of habitat loss for bighorn sheep in Colorado.
Ward, T.J., M. Asce, S.J. Krammes, and S. Bolton, A COMPARISON OF RUNOFF AND SEDIMENT YIELDS FROM BARE AND VEGETATED PLOTS USING RAINFALL SIMULATION.
The overall effects of vegetative cover on runoff and sediment yields are well known. Many references to the qualitative and quantitative effects can be found throughout the natural science and engineering literature. What is lacking are studies which detail the effects of cover on specific hydrologic and hydraulic processes of their representative parameters so that the results may be used for simulation modeling. Data from 108 small plot rainfall simulator experiments on pinyon-juniper woodlands in Arizona and New Mexico were analyzed to determine quantifiable effects of cover on hydrologic and sediment yield parameters. Significant effects were identified and linear models were developed to quantify them. Other published techniques for rangelands were applied to the data with limited success.
Wasson, G.E., THE AMERICAN INDIAN RESPONSE TO THE PINYON JUNIPER CONFERENCE., Proceedings Pinyon-Juniper Conference, Jan. 1987, p. 38-41.
The American Indian has occupied pinyon-juniper lands for eons with total harmony with Mother Earth. Values of the Indian and U.S.European are completely different; the former emphasize living in harmony with all other living things, the latter focus on monetary rewards and technical change, with polluting side effects. By adopting the Indian method of management, pinyon-juniper lands can be restored to full productivity. Trees should not be cut, rather pine nuts should be harvested and processed into high protein food for starving people on our planet.
Weise, D.R., SURVIVAL OF DAMAGED SINGLELEAF PINYON ONE YEAR AFTER WILDFIRE, USDA Forest Service General Technical Report RM-191, Ft. Collins, CO. ,In: J.S. Krammes (tech. coord.), Effects of Fire Management of Southwestern Natural Resources, 1990, p. 229-23 1.
Welden, C.W., William L. Slauson, and Richard T. Ward, SPATIAL PATTERN AND INTERFERENCE IN PINYON-JUNIPER WOODLANDS OF NORTHWESTYLE="COLORADO, Great Basin Naturalist, 1990, p. 3 13-3 19.
The local spatial arrangement of the coniferous trees Pinus edulis and Juniperus osteosperma was mapped In two woodland stands and measured In two shrub-dominated stands In the semiarid Peceance Basin of northwest Colorado. In the woodlands, small trees were often clumped, while medium and large trees were either randomly or uniformly dispersed. Significant regressions were obtained between a tree's basal area or canopy area and the area of its Dirichlet domain (the region closer to it than to any other tree). Both findings from the woodland stands accord with results obtained by other workers in other vegetation. Like earlier workers, we interpret these patterns Indicate density-dependent mortality and density-dependent depression of growth rates among the trees In the woodlands. In contrast, the trees in the shrub-dominated stands are located at random with respect to each other. However, they are strongly associated with shrub cover. Apparently, tree seeds arrive in these stands primarily by long-distance dispersal, and the establishment of seedlings is more likely In the shade of shrubs.
Wells, P.V., SYSTEMATICS AND DISTRIBUTION OF PINYONS IN THE LATE QUATERNARY, Proceedings Pinyon-Juniper Conference, Jan. 1987, p. 104-108.
The wide prevalence of Pinyon-juniper woodlands at very low elevations in the hot-desert providences of the southwest is well established by a quarter-century of paleobotanical studies on Neotoma (wood rat) middens, dated back to the last glacial. The PJ type shifted upward some 1,000-1,500 m in elevation and has extended northward In to the Great Basin and Rocky Mountains some degrees of latitude (640 km), mainly during the early Holocene. In spite of these shifts (no doubt previously reiterated during glacial/interglacial cycles), there is a consistency as to taxon of pinyon pine recorded as exquisitely preserved fossils in the Pleistocene period at low desert elevations and the nearest living pinyon surviving on higher mountains of each desert province. The first examples in the northern Mohave desert of Pinus monophylla and in the Chihauhuan Desert of P. remota have been augmented in the Sonoran Desert (c. Baja California: P. quadrifolia; se. California and south Arizona: P. edulis fallax) and northernmost Chihauhuan Desert: P. edulis. Thus, the PJ type is a very ancient set of plant communities of remarkable stability despite its migrational history.
Weltz, M. and K.M. Wood, SHORT DURATION GRAZING IN CENTRAL NEW MEXICO: EFFECTS ON INFILTRATION RATES, Journal of Range Management, vol. 39, 1986, p. 365-368.
The objectives of this study were to determine the influence of short duration grazing, continuous grazing, and grazing exclusion on infiltration rates on 2 range sites in southcentral and eastcentral New Mexico.
Short duration grazing had no beneficial effect on the hydrology of 2 different range sites. The terminal infiltration rates of both short duration grazing systems, after the cattle had grazed the area, were about one-half the terminal infiltration rate of the same area before the cattle grazed the area. Cattle distribution within the different grazing treatments had no effect on infiltration rates at 0.4, 0.8, and 1.2 km away from water for a moderate continuous, heavy continuous, and a short duration grazing system. Moderate continuous grazing was superior to heavy continuous and short duration grazing, based on the hydrologic variables evaluated.
West, N.E., D.R. Cain, and G.F. Gifford, BIOLOGY, ECOLOGY, AND RENEWABLE RESOURCE MANAGEMENT OF THE PYGMY CONIFER
WOODLANDS OF WESTERN NORTH AMERICA, Utah State University Agriculture Experiment Station Reserve Paper No. 12, Logan, Utah., 1973.
West, N.E., K.H. Rea, and R.J. Tausch, BASIC SYNECOLOGICAL RELATIONSHIPS IN JUNIPER-PINYON WOODLANDS, The Pinyon Juniper Ecosystem: a Symposium. Utah State University, Logan, UT., 1975, p. 41-52.
West, N.E., R.J. Tausch, K.H. Rea. and P.T. Tueller, PHYTOGEOGRAPHICAL VARIATION WITHIN JUNIPER-PINYON WOODLANDS OF THE GREAT BASIN, Great Basin Naturalist Memoirs, vol. 2, 1978, p. 119-136.
West, N.F,., FACTORS AFFECTING TREATMENT SUCCESS IN THE PINYON-JUNIPER TYPE, Proceedings of the Second Utah Shrub Ecology Workshop, 1982, p. 21-33.
Substantial increase in forage for ungulates in pinyon-juniper woodlands are possible only through type conversions. Criteria for success of these projects depend on management objectives. Factors that influence success can be divided into pre-treatment, and posttreatment categories. Each category can further be divided into environmental, biological, and managerial subdivisions. The literature has been reviewed for interrelationships of ecological and management influences on success of type conversions. it is foolhardy to rely on only one or even a few factors to predict success, thus a list of factors has been developed that have positive and negative influences on each of three major planned type conversions approaches: chaining/cabling, prescribed burning and herbicidal treatments. If most of the predeterminable and controllable factors are positive and economic and social constraints are low or absent, then treatment of a given site may be successful. Uncontrollable factors such as drought may still cause the project to fail. Treating relatively small areas in any one year minimizes the cumulative effect of such unpredictable deterrents. This author doubts whether there are many sites remaining in Utah which should be chained or cabled. The environmental conditions for success via this treatment are more limited. Costs and social objections against such treatment make chaining/cabling a much less viable option now and likely in the future. Prescribed burning and second generation pelleted herbicides have the most promise for retreatment and initial type conversions. They have, however, attendant costs and shortcomings that have to be examined on a case-by-case basis.
West, N.E., SUCCESSIONAL PATTERNS AND PRODUCTIVITY POTENTIALS OF PINYON-JUNIPER ECOSYSTEM, National Research Council/National Academy of Science, 1986, p. 301-1332.
About 11 species of pinyon and 9 species of juniper trees dominate the woodlands occupying about 325,000 Km2 (60 million acres) in semi-arid portions of the western U.S. The present area is much greater than that found in pre-Columbian times largely because livestock grazing has lead to reduce competition from herbaceous plants, less frequent fires and other associated causes for increase in tree populations. Reduction of livestock numbers did not earlier, nor does not now, offer any hope of reversing these successional changes. With fire removed as a controlling factor, the much greater physiological efficiency of trees leads to their full climatic climax expression. Loss of forage in the woodland understory caused land managers to conduct programs of tree destruction during the 1940's through early 1960's. These type conversions were largely designed to benefit the livestock industry. Increases in cost of manipulation and legislation that forced closer scrutiny of full ecological impacts have inhibited tree reduction programs in recent years. The current decline in management action will probably result in continuing soil erosion and loss of site potential. Therefore, it is suggested that the following, less costly actions be undertaken: (1) Retreatment of sites that were poorly managed following seeding with grass and browse; (2) Prompt seeding of desirable forage species onto sites affected by wildfire; (3) Accelerated use of prescribed burning of stands of trees where trees are sparse and understory fine fuels adequately carry fire and provide seed sources; (4) Increased research and pilot testing of second generation pelletized herbicides to curtail tree advances onto sites that were originally grasslands, brushlands, or savannahs; (5) Collaboration with foresters, wildlife managers, and others to plan small patchwise rotational tree harvesting schemes on the areas that have always had some, but now have thickened, stands of even-aged tree regeneration.
West, N.E. and Nicholas S. Van Pelt, SUCCESSIONAL PATTERNS IN PINYON-JUNIPER WOODLANDS, Proceedings - Pinyon-Juniper Conference, Jan. 1987, p. 43-52.
Managers and students of pinyon-juniper woodlands must have information on how these ecosystems respond through time to human and natural influences. We document the importance of plant succession and describe six kinds of change that operate within present-day woodlands. Our purpose is to broaden thinking on woodland dynamics and to describe how intervention and research can be designed to give more definite outcomes, answers, and predictions. Many more successional sequences need to be obtained, using a variety of techniques, starting points, and disturbance regimes.
West, N.E., INTERMOUNTAIN DESERTS, SHRUB STEPPES, AND WOODLANDS, In: M.G. Barbour, and W.D. Billings (eds.), North American Terrestrial Vegetation. Cambridge University Press, New York., 1988, p. 208-230.
West, N.E., R.J. Tausch, K.H. Rea, and P.T. Tueller, TAXONOMIC DETERMINATION, DISTRIBUTION, AND ECOLOGICAL INDICATOR VALUES OF SAGEBRUSH WITHIN THE PINYON-JUNIPER WOODLANDS OF THE GREAT BASIN, Journal of Range Management, 1978, p. 87-92.
Various sagebrush taxa are major understory components of most Great Basin pinyon-juniper woodlands. Improved understanding of their identification, distribution, and ecological indicator significance Is necessary to interpret site differences for these ranges. Morphology within sagebrush taxa is so variable that chromatographic determination is more easily and objectively relied upon for identification. Big sagebrush is so widespread and likely genetically diverse that sub-specific designations are more helpful in reading site conditions. The various sagebrush taxa are found in particular situations in Great Basin woodlands. Climatic differences explain the Basin-wide distributions much more than geologic, landform, or soil conditions. SOILS and exposure become more Important on the local scale. Presence of a particular sagebrush taxon within pinyon-juniper woodlands can be used for comparisons of site favorableness provided one understands the general distribution of the other sagebrush taxa.
White, G.C., R.A. Garrot, R.M. Bartman, L.H. Carpenter, and A.W. Alldredge, SURVIVAL OF MULE DEER IN NORTHWESTYLE="COLORADO, Journal of Wildlife Management, vol. 51, 1987, p. 852-859.
Survival of mule deer in Piceance Basin, Colorado, was measured with radio telemetry for 3 years on 1 study area and 4 years on another. Survival rates for deer >6 months old were estimated for yearly intervals beginning 1 December, male and female (P=0.567). There were significant differences (P=0.250) in survival rates among years for fawns, and adult females, and between age classes (P<O.001). The mean survival rate for each respective age class was 0.244 + 0.056 (SE) and 0.832 + 0.030 (SE). Mean fawn survival was similar on the 2 study areas even though major mortality cases differed (P<O.001). From 46-76% of fawns on 1 area died from predation each year, whereas 49-83% of those on the other area starved. A Cox model analysis of S fawn body size variables revealed weight as the best predictor of overwinter survival. However, this was not consistent among years on 1 area, which suggested that not all mortality selected for small-bodied fawns. Average weight on 1 December was largest for fawns that lived, intermediate for fawns taken by predators, and smallest for fawns that starved. Variability in 5 body size parameters was consistently greatest for fawns taken by predators, suggesting little selection, whereas variability was smallest for fawns that lived, indicating selection for survival.
Whitford, W.G., SOIL FAUNA AS REGULATORS OF DECOMPOSITION AND NITROGEN CYCLING IN PINYON-JUNIPER ECOSYSTEMS, Proceedings -Pinyon-Juniper Conference, Jan. 1987, p. 365-368.
There was no correlation between decomposition rate of buried barley straw and population of soil fauna. There was net immobilization of nitrogen in decomposing straw during the first 100 days followed by net mineralization. Net nitrogen mineralization was correlated with high population numbers of fungus feeding tarsonemid mites.
Wilcox, B.P. and K.M. Wood, HYDROLOGIC IMPACTS OF SHEEP GRAZING ON STEEP SLOPES IN SEMIARID RANGELANDS, Journal of Range Management, vol. 41, 1988, p. 303-306.
Infiltration, sediment concentration of runoff, and sediment production from lightly grazed and ungrazed semiarid slopes were compared using a hand-portable rainfall simulator. The study slope was located in the Guadalupe Mountains of southeastern New Mexico. Average slope steepness was 50%. The objective of this study was to determine the impacts of light grazing by sheep ( 10 ha/AU) on steep slope infiltrability and sediment production. Infiltrability on the grazed slopes was 12-17% lower than on the ungrazed slopes. These results are comparable to what has been reported from moderate slope gradients. Sediment concentration of runoff from the lightly grazed slopes was significantly higher than from the ungrazed slopes only at the end of the dry run (45 min.) Sediment production was significantly greater from the grazed slopes for the dry run, but not the wet run. Percentage difference of sediment production between the grazed and ungrazed slopes was well within the range published for moderate slope conditions. These data give no indication that steep slopes (30-70%) in semiarid regions are any more hydrologically sensitive to light grazing than are moderate slopes.
Wilcox, B.P.; K.M. Wood and J.M. Tromble, FACTORS INFLUENCING INFILTRABILITY OF SEMIARID MOUNTAIN SLOPES, Journal of Range Management, vol. 41, 1988, p. 197-206.
The objective of this research was to determine the effects of selected vegetation, soil, rock, and slope variables on infiltration of semiarid rangelands with slope gradients ranging from O-70%. Analyses were made on 2 sets of data collected a year apart in the Guadalupe Mountains of New Mexico and consisted of Pearson and partial correlation analysis of the dependent infiltration variables and independent site veronals. In addition, infiltration was regressed against uncorrelated factors produced by factor analysis. Vegetal cover and biomass strongly influenced infiltration. The relative importance of grasses, shrubs or litter was dependent on their respective abundance, especially as soil water storage became satisfied. Infiltration was negatively correlated with rock cover and the smallest rock size fragments were the most negatively related. When the effects of vegetal cover and slope were removed (using partial correlation analysis) however, the medium sized rock fragments (26-150 mm) were positively related to infiltrability, and the smallest rock fragments (2-12 mm) were negatively related. Partial correlation analysis also suggested a positive correlation between infiltrability and slope gradient.
Wilkins and J.M. Klopatek, PLANT WATER RELATIONS IN ECOTONAL AREAS OF PINYON-JUNIPER AND SEMI-ARID SHRUB ECOSYSTEM, Proceedings -Pinyon-Juniper Conference, Jan. 1987, p. 412-417.
Plant-soil water potential parameters for pinyon (Pinus edulis), Juniper (Juniperus osteosperma), and several Great Basin shrub species were measured on Black Mesa in northeastern Arizona. internal water potential components from pressure-volume curves were correlated with whole plant water potential, soil moisture, and atmospheric vapor-pressure deficit to compare and rank species according to their drought-resistance capabilities on disturbed coal mine sites. Statistical analyses showed both intra- and intercommunity differences. Mean site water potentials were significantly more negative in the shrub-steppe community than in the pinyon-juniper woodland.
Williams Gerald F.; and George B. Coltharp, FACTORS INFLUENCING INFILTRATION AND EROSION ON CHAINED PINYON-JUNIPER SITES IN UTAH, Journal of Range Management, Vol. 25, May 1972, p. 201-205.
Relations between vegetal and edaphic factors and infiltration rates and erosion measured on 550 infiltrometer plots at chained pinyon-juniper sites in Utah were analyzed by multiple regression analysis. Those factors most important for predicting infiltration rates (regardless of time intervals) included total porosity in the 0-3 inch bare soil surface, soil texture in the 0-3 inch layer of soil, and crown cover (percent or tons per acre). The ability to predict infiltration rates (as determined by R2)) varied with time and location. Factors that influence sediment discharge were so variable from one geographic location to another that no consistent relation was found.
Wilson, D.E., ECOLOGICAL DISTRIBUTION OF THE GENUS PEROMYSCUS, The Southwestern Naturalist, vol. 13, December 1968, p. 267-274.
An analysis of the ecological distribution in the Sandia Mountains, New Mexico, of five species of Peromyscus is presented. Variables considered include elevations, exposure, vegetation, and mammalian associates. The five species occur sympatrically, but generalized ecological separations can be seen.
Wittie, R.D. and K.C. McDaniel, EFFECTS OF TEBUTHIURON AND FIRE ON PINYON-JUNIPER WOODLANDS IN SOUTHCENTRAL NEW MEXICO, USDA Forest Service General Technical Report RM-191, Ft. Collins ,In: J.S. Krammes (tech. coord.), Effects of Fire Management of Southwestern Natural Resources, 1990, p. 174-179.
Woffinden, N.D. and J.R. Murphy, DECLINE OF A FERRUGINOUS HAWK POPULATION A 20 YEAR STUDY, Journal of Wildlife Management, 1989, p. 1127-1132.
A central Utah population of ferruginous hawks became extinct from 1967 to 1986. The decline was initially correlated with a black-tailed jack rabbit population crash. The hawk populations did not respond numerically to an increase in prey numbers. Occupation of nesting territories varied; S of the 21 territories contained nesting pairs in only 1 year and 2 other territories contained nesting pairs in 11 and 14 years during the study. The failure of the population to increase as prey increased and habitat vacancy occurred may be explained by low production and nonadultism. Estimated first year and adult mortality rates of 66 and 25% scale favorably with mass. Seral vegetative changes may be depressing jack rabbit population recovery and hence be responsible in some degree for low numbers of ferruginous hawks.
Woodbury, A.M. and C. Cottam, ECOLOGICAL STUDIES OF BIRDS IN UTAH, University of Utah Biological Serial No. 7, Salt Lake City, 1962.
Wright, H.A., L.F. Neuenschwander, and C.M. Britton, THE ROLE AND USE OF FIRE IN SAGEBRUSH-GRASS AND PINYON-JUNIPER PLANT COMMUNITIES, USDA Forest Service General Technical Report INT-58, 1990, p. 48.
Wright, H.A., ROLE OF FIRE IN THE MANAGEMENT OF SOUTHWESTERN ECOSYSTEMS, USDA Forest Service General Technical Report RM-191, Ft. Collins., In: J.S. Krammes (tech. coord.), Effects of Fire Management of Southwestern Natural Resources, 1990.
Young, R.P., FIRE AS A VEGETATION MANAGEMENT TOOL IN RANGELANDS OF THE INTERMOUNTAIN REGION, USDA Forest Service General Technical Report INT-157, Ogden, UT. In: S.B. Monsen, and N. Shaw (compilers), Managing Intermountain Rangelands Improvement of Range and Wildlife Habitats, 1983, p. 18-31.
Young, J.A. and J.D. Budy, ENERGY CRISIS IN 19TH CENTURY WOODLANDS, Proceedings-Pinyon-Juniper Conference, Jan. 1987, p. 23-28.
The pinyon-juniper woodlands of the Great Basin were a vital source of wood products for the mining industry from the 1860's to the 1920's. Pinyon and juniper were cut extensively for fuel wood and/or the production of charcoal, the only available fuel or energy source for the smelters of central Nevada. Firewood and fence posts for ranches were also important uses of pinyon-juniper. Deforestation by cutting and wildfire continued unabated until the 1920's and 1930's, when fossil fuels, wood substitutes, and fire control combined to decrease use of this vegetation type.
Young J.A. and R. Evans, STEM FLOW ON WESTERN JUNIPER (JUNIPERUS OCCIDENTALIS) TREES, Proceedings - Pinyon-Juniper Conference, Jan. 1987, p. 373-381.
Stem flow is the water from precipitation that is intercepted by plant canopies and conveyed down the outside of the stems to wet the soil at the base of the plant. For western juniper (Juniperus occidentals, Hook) trees, stem flow was only a small fraction of the precipitation intercepted by the canopy. However, this moisture may be important in the nutrient flux of the trees. The first stem flow in the fall after the summer drought was enriched in nitrate-nitrogen although the quantity of nitrogen per unit area was small. The enrichment of the stem flow may not be as important as the precise placement of the moisture at the base of the tree. The combination of favorable moisture and temperature conditions at the base of the tree leads to litter decay and nitrification. The root system of the trees had many fine roots in the trunk base area.
Zanoni, T.A. 1978. The American junipers of the section Sabina (Juniperus, Cupressaceae)--A century later. Phytologia 38:433-454.
Zanoni, T.A. and R.P. Adams. 1979. The genus Juniperus (Cupressaceae) in Mexico and Guatemala: Synonymy, key, and distributions of the taxa. Bol. Soc. Bot. México 38: 83--131.
- A bibliography containing over 2,500 references to the literature concerning fossil and Recent species of bivalves in the genus Corbicula is presented for the period 1774 ‑ 2005.
- A bibliography containing over 2,500 references to the literature concerning fossil and Recent species of bivalves in the genus Corbicula is presented for the period 1774 2005.