Mountain Research Station Research Articles

Evaluating FIA Forest Inventory Data for Monitoring Mexican Spotted Owl Habitat: Gila National Forest Example

Abstract The habitat of the Mexican spotted owl must be monitored because of the owl's “threatened” status under the Endangered Species Act of 1973. A possible data source for habitat monitoring is the network of permanent plots maintained by Forest Inventory and Analysis (FIA), USDA Forest Service, Rocky Mountain Research Station. This article demonstrates how FIA data might be used to calculate stand density measures for monitoring owl habitat. Test results for New Mexico's Gila National Forest showed 26% of the mixed conifer and 35% of the pine-oak as suitable owl habitat for a forest structure scenario. Ninety-five percent confidence intervals for these estimates were from ±20 to ±35% for the mixed-conifer habitat area; for pine-oak they were ±50 to ±73%. Although results are encouraging for using FIA data to monitor owl habitat, critical linkage needs to be established between the owl's home-range requirements and the stand-density metrics tested. West. J. Appl. For. 15(4):195-199.

Chemical ionization mass spectrometer for long-term measurements of atmospheric OH and H 2SO 4

An atmospheric pressure/chemical ionization mass spectrometer (AP/CIMS) has been developed for continuous long-term measurements of atmospheric OH and H 2SO 4. The corresponding methods both involve chemical ionization of H 2SO 4 by NO 3 − ions with OH being first titrated by excess SO 2 to form equivalent concentrations of H 2SO 4 in the system. The chemical ionization mass spectrometry (CIMS) system has been operated since April 1998 at the Meteorological Observatory Hohenpeissenberg, a mountain research station of the German Weather Service in South Germany. A technical description of the apparatus is presented followed by a detailed estimate of uncertainties in calibration and ambient air measurements resulting from changes in instrumental and/or ambient parameters. Examples from both calibration runs and ambient air measurements are shown. For the present system and operating conditions accuracy, precision, and detection limit are estimated to be 39%, 30%, and 3 × 10 4 molecules cm −3 for H 2SO 4, and 54%, 48%, and 5 × 10 5 molecules cm −3 for OH measurements, respectively, based on 5 min signal integration.

Intermittent vs continuous hypoxia: effects on ventilation and erythropoiesis in humans

Recently, we showed that 5 days of normobaric intermittent hypoxia at rest (IH; 2 hours daily at 3,800 m simulated altitude; partial pressure of inspired oxygen 90 torr) can induce an increase in the isocapnic hypoxic ventilatory response (HVR) and blood reticulocyte count. The purpose of the present study was to compare these data with continuous exposure to the same hypoxic level. Four of the same subjects were exposed, a year later, to 2 days of continuous hypoxia (CH), and 4 different subjects were exposed to 8 weeks of CH, both at the White Mountain Research Station (3,800 m altitude, barometric pressure approximately 489 torr). Inspired minute ventilation (VI), end-tidal partial pressure of carbon dioxide, arterial oxygen saturation (SaO2[sat]), hematocrit, and hemoglobin concentration were measured at different times during the continuous exposures. The HVR was expressed as the increase in V1 per 1% decrease in SaO2. The HVR showed no significant difference in the control values 1 year apart (IH, 0.06 +/- 0.03; CH2d (2 days' continuous hypoxia), 0.19 +/- 0.07 L x min(-1) x %sat(-1); means +/- SE), and the HVR values were similar after 2 days of IH compared to CH (0.42 +/- 0.26 and 0.51 +/- 0.22 L x min(-1) x %sat(-1), respectively). On the new subjects after 2 weeks of CH, the HVR showed a maximum increase, similar to the increase observed after only 5 days of IH, hemoglobin concentrations and hematocrit were significantly increased (45.0 +/- 2.7% vs 51.5 +/- 3.0% and 14.5 +/- 0.7 vs 17.2 +/- 1.0 g x dL(-1), respectively). The HVR did not change significantly from week 2 to 8 of CH, whereas hematological data were still increasing at the end of the 8 weeks. Changes in ventilatory oxygen sensitivity induced by IH and CH are similar in magnitude but occur with different time courses. The effects of IH on erythropoiesis are significant but fewer than on CH.

Twentieth-Century Change in the Climate Record for the Front Range, Colorado, U.S.A.

The long-term climate records of the Mountain Research Station (MRS) at the University of Colorado cover a range of elevations from the lower montane forest zone (~2000–2400 m), through the upper montane forest (~2400–2800 m) and subalpine forest (~2800–3300 m) to the alpine tundra (>3300 m) on Niwot Ridge, Colorado. Temperature records from all four MRS sites and the additional high plains site of Longmont (1509 m) are analyzed for the period 1952–1997, after extraction of much extra data from the original thermograph charts. The records are adjusted for instrumental changes where necessary and all four records are judged to be homogenous. Contrasting temporal trends are uncovered at the various elevations with warming at middle elevations and absolute cooling above the treeline in the alpine tundra. The resulting increased surface-based lapse rates do not arise from changes in relative frequencies of airflow types as is shown by a synoptic analysis based on objective airflow indices. Lapse rate increases are most systematic for synoptic classes with westerly components and during fall, winter, and spring. Climate at high elevations of the Front Range appears to be responding in an unusual way to global-warming influences.

Twentieth-Century Change in the Climate Record for the Front Range, Colorado, U.S.A.

The long-term climate records of the Mountain Research Station (MRS) at the University of Colorado cover a range of elevations from the lower montane forest zone (~2000–2400 m), through the upper montane forest (~2400–2800 m) and subalpine forest (~2800–3300 m) to the alpine tundra (>3300 m) on Niwot Ridge, Colorado. Temperature records from all four MRS sites and the additional high plains site of Longmont (1509 m) are analyzed for the period 1952–1997, after extraction of much extra data from the original thermograph charts. The records are adjusted for instrumental changes where necessary and all four records are judged to be homogenous. Contrasting temporal trends are uncovered at the various elevations with warming at middle elevations and absolute cooling above the treeline in the alpine tundra. The resulting increased surface-based lapse rates do not arise from changes in relative frequencies of airflow types as is shown by a synoptic analysis based on objective airflow indices. Lapse rate increases are most systematic for synoptic classes with westerly components and during fall, winter, and spring. Climate at high elevations of the Front Range appears to be responding in an unusual way to global-warming influences.

Damage Assessment in Christmas Tree Plantations following Vegetation Control with Sheep and Geese

Abstract Christmas tree farming in the Southern Appalachian Mountains is a potentially profitable but labor and chemical intensive enterprise. Control of competition from unwanted vegetation usually requires multiple applications of herbicides. Because geese and sheep have traditionally been used as “weeders” in orchards and cropland, the objective of this experiment was to evaluate the potential of these animals for herbaceous vegetation control in Christmas tree plantations. Three types of field trials were conducted at the Upper Mountain Research Station located near Laurel Springs, NC, during two growing seasons (1992 and 1993) to evaluate the natural browsing tendency displayed by sheep and different breeds of geese for different tree species. Food aversion training in a Fraser fir plantation was a special focus of the trials. Sheep and geese were managed to consume herbaceous vegetation through controlled, rotational grazing. Herbage mass of the residue was maintained between 693 and 2,000 kg/ha. Damage observed on four tree species (white pine, Fraser fir, Canadian hemlock, Colorado blue spruce) by “weeder” sheep and geese was dependent on animal species or breed. Untrained sheep and Pilgrim geese were most damaging to 1 yr old transplants (damage scores of 5.3 to 2.3). Trees with damage scores of less than 7 were judged to have reduced commercial potential. "Training" sheep to avoid browsing trees (using a gelatin capsule containing lithium chloride to affect feed selection) is a promising technique worthy of further research. South. J. Appl. For. 23(1):11-15.

The 18O/16O and 17O/16O ratios in atmospheric nitrous oxide: A mass-independent anomaly

Measurements of the oxygen isotope ratios (18O/16O and 17O/16O) in atmospheric nitrous oxide (N2O) from La Jolla, Pasadena, and the White Mountain Research Station (elevation, 3801 meters) in California and the White Sands Missile Range in New Mexico show that N2O has a mass-independent composition. These data suggest the presence of a previously undefined atmospheric process. The La Jolla samples can be explained by a mixing between an atmospherically derived source of mass-independent N2O and biologically derived mass-dependent N2O. Possible origins of the mass-independent anomaly in N2O are discussed.

Mountains and Plains

EcologyVolume 78, Issue 5 p. 1610-1611 Book Review Mountains and Plains William D. Bowman, William D. Bowman University of Colorado, Mountain Research Station and EPO Biology, Campus Box 334, Boulder, Colorado 80309Search for more papers by this author William D. Bowman, William D. Bowman University of Colorado, Mountain Research Station and EPO Biology, Campus Box 334, Boulder, Colorado 80309Search for more papers by this author First published: 01 July 1997 https://doi.org/10.1890/0012-9658(1997)078[1610:MAP]2.0.CO;2Read the full textAboutPDF ToolsRequest permissionExport citationAdd to favoritesTrack citation ShareShare Give accessShare full text accessShare full-text accessPlease review our Terms and Conditions of Use and check box below to share full-text version of article.I have read and accept the Wiley Online Library Terms and Conditions of UseShareable LinkUse the link below to share a full-text version of this article with your friends and colleagues. Learn more.Copy URL Share a linkShare onFacebookTwitterLinked InRedditWechat Volume78, Issue5July 1997Pages 1610-1611 RelatedInformation

Term ovine placental vasculature: Comparison of sea level and high altitude conditions by corrosion cast and histomorphometry

The placental vascular architecture differs significantly at high altitude from that at sea level in the human and guinea-pig. Four sheep between 137 and 140 days of gestation, kept near sea level throughout gestation, were used as a normoxic control group for comparison of the placental vasculature with 10 other ewes, kept at high altitude (3820 m above sea level; Barcroft Laboratory, White Mountain Research Station, CA, USA). Placentomes from both groups were prepared for histology and scanning electron microscopy of vascular corrosion casts. Singular perfusion of fetal placentae, as well as combined maternal/fetal injection was performed. The influence of long-term hypoxaemia was determined by qualitative and semi-quantitative evaluation of corrosion casts and histological sections. The fetal vessel casts show a distinct difference in the arrangement of vessels of all sizes in response to long-term hypoxaemia. In the control group, stem arteries and veins are straight and parallel. In contrast, this is much less evident in the hypoxaemic group because arterioles and venules branch off the stem vessels more frequently and in an irregular manner. This leads to a capillary bed that is much more dense due to increased branching and capillary coiling. These observations are confirmed by histomorphometry. In the fetal vessels of high altitude sheep placentomes, we observed a decreased number of vascular cross sections (21.6 ± 4.7 sem versus 27.7 ± 4.0 sem; P=0.02). However, the average luminal size per cross section (77.9 ± 10.5 μm 2 sem versus 59.4 ± 7.4 μm 2 sem; P=0.004) was increased at high altitude and the percentage of lumina of the total area (5.7 ± 0.5 sem versus 5.3 ± 0.3 sem; P=0.09) indicated a trend towards an increase. In maternal vessels of high altitude placentomes, the number of vessel cross sections (6.5 ± 0.7 sem versus 6.0 ± 0.5 sem; P=0.2) remained unchanged, whereas the average luminal size (1108 ± 122 μm 2 sem versus 844 ± 77 μm 2 sem; P < 0.001) and the percentage of lumina out of the tot area (20.9 ± 1.8 sem versus 17.5 ± 1.7 sem; P<0.001) were increased. The interhaemal distance appeared to be slightly but not significantly increased at high altitude. These findings indicate that at high altitude the sheep placenta develops an increased materno-fetal absorptive surface to help guarantee substance exchange.

Evidence of preferential directions for gravity wave propagation due to wind filtering in the middle atmosphere

All‐sky TV images of wave structure in the near‐infrared hydroxyl (OH) nightglow emission were recorded over a 3‐month period during May, June, and July 1988 from a high‐altitude site at the Mountain Research Station (40.0° N, 105.6° W, 3050 m), near Nederland, Colorado. Well‐defined, coherent wave patterns associated with the passage of short period (&lt;1 hour) gravity waves were observed on a total of 22 occasions. The wave motions exhibited similar spatial and temporal properties during each month but a distinct tendency for northward propagation (68% of the wave azimuths within ± 40.0° N), with some eastward motion in May and June, was observed throughout the campaign. Although it is theoretically well known that upward propagating gravity waves can be blocked at a critical layer produced by the interaction of the waves with the horizontal background wind, observational evidence of this phenomenon is rare. To investigate the possibility that the asymmetry in the wave propagation directions was caused by the critical layer, a model based on mean climatological background winds and numerical tidal wave modes valid for any mid‐latitude site and time of the year was constructed to show the regions forbidden to upward gravity wave propagation from critical layer theory. These “blocking diagrams” which vary with height and time were constructed for the OH altitude (∼87 km) for the present paper. Comparison of the predicted (i.e., least restricted) and the observed directions of the wave motion show almost complete agreement. This suggests that middle atmospheric winds can play an important role in determining the flux and the azimuthal distribution of short‐period waves reaching the upper atmosphere.

A liquid-helium-cooled absolute reference cold load for long-wavelength radiometric calibration

We describe a large (78 cm) diameter liquid-helium-cooled blackbody absolute reference cold load for the calibration of microwave radiometers. The load provides an absolute calibration near the liquid-helium (LHe) boiling point, with total uncertainty in the radiometric temperature of less than 30 mK over the 2.5–23-cm wavelength (12–1.3 GHz) operating range. Emission from those parts of the cold load not immersed in LHe is ≤25 mK and the reflection coefficient is ≤3.5×10−4. This cold load has been used at several wavelengths at the South Pole, Antarctica and at the White Mountain Research Station, California to calibrate spectral measurements of the cosmic microwave background radiation. For the instruments operated at 20-, 12-, 7.9-, and 4.0-cm wavelength at the South Pole, the total corrections to the LHe boiling-point temperature (∼3.8 K) were 48±23, 18±10, 10±18, and 15±16 mK, respectively. In operation, the average LHe loss rate was ≤4.4 ℓ/h, allowing day-long periods of operation without a LHe fill. The boiloff rate is not strongly dependent on the radiative load at the aperture, yielding very stable operation and radiometric performance. Design considerations, radiometric and thermal performance, and operational aspects are discussed. A comparison with other LHe-cooled reference loads including the predecessor of this cold load is given.

Interdisciplinary Physics: Research Topics in Studying Man's Environment

AbstractThe interdisciplinary study of the environment using tracer elements is here described for three examples: The climate of the past, the gas exchange between atmosphere and ocean and the natural carbon cycle. In the first, the isotope ratios of hydrogen and of oxygen in ocean sediments, groundwater, polar ice and in tree rings was found to give much useful information. In the study of gas exchange which is controlled by a thin molecular diffusion boundary layer on the liquid side of the interface it was found that the exchange is more strongly influenced by the presence of surface waves than had been expected. To increase the understanding of the natural carbon cycle, radon-222 was used as an auxiliary tracer. With this nuclide as a reference, the diurnal and seasonal variations of the CO2 concentration at a mountain research station were analysed, and the source or sink fluxes causing these variations were calculated.

Simultaneous measurements of atmospheric emissions at 10, 33, and 90 GHz

As part of a larger experiment to measure the cosmic microwave background radiation spectrum, frequent simultaneous measurements of microwave thermal emissions from the earth's atmosphere have been made at 10, 33, and 90 GHz. We have performed these measurements at two separate locations, Berkeley, California, and the White Mountain Research Station located near Bishop, California, which differ greatly in altitude and climatic conditions. Typical values of the atmospheric antenna temperature measured in Berkeley (250‐m elevation) during good weather are 2.54±0.29, 12.4±0.3, and 34.3±0.5 K for 10, 33, and 90 GHz, respectively. Corresponding values measured at White Mountain (3800 m) are 1.11± 0.04, 4.48±0.18, and 11.0±0.1 K. Because the measurements are simultaneous in nature, correlations between the measurements taken at the various frequencies provide constraints on models of the microwave emission of the earth's atmosphere, especially models describing atmospheric emission as a function of precipitable water content.

Spruce Spider Mite Control, 1981

Abstract A 1980 study showed that 1.5 oz/gal or 3.0 oz/gal of Safer’s Insecticidal Soap applied by backpack blower or hydraulic sprayer was efficacious for controlling spruce spider mites. The present study was a temporal and spatial replication of the lower application rate (1.5 oz/gal) applied by both backpack mist blower and hydraulic sprayer. Approximately 300 trees at the Mountain Research Station, Waynesville, NC were divided into 6 blocks. Two blocks were randomly selected as controls while the remaining blocks were treated with 1.5 oz/gal of soap and applied with a Solo backpack mist blower. Ten, 5-cm twig samples were taken from the center of each plot and analyzed for eggs, larvae, nymphs and adults of the spruce spider mite. Twig samples were taken before treatment and 1, 2, and 4 wks after treatment. Two 50-tree plots, in Ashe County, NC, were divided into 2 blocks each. Each plot had a treated block and a control block. The treated blocks were sprayed by hydraulic sprayer with 1.5 oz/gal of soap. One, 5-cm twig sample was taken from each tree in all 4 blocks and analyzed for eggs, larvae, nymphs, and adults of the spruce spider mite. Twig samples were taken before treatment and 1 and 3 wk after treatment.

Living on the 700 Millibar Surface: The Mountain Research Station of the Institute of Arctic and Alpine Research

(1977). Living on the 700 Millibar Surface: The Mountain Research Station of the Institute of Arctic and Alpine Research. Weatherwise: Vol. 30, No. 6, pp. 233-238.

The Indian Peaks section of the Continental Divide seen from the upper limits of the krurnmholz, forest-tundra ecotone, above INSTAAR's Mountain Research Station.

The Indian Peaks section of the Continental Divide seen from the upper limits of the krurnmholz, forest-tundra ecotone, above INSTAAR's Mountain Research Station.

The Indian Peaks krummholz section of the Continental Divide seen from the upper limits of the forest-tundra ecotone above INST AAR's Mountain Research Station.

The Indian Peaks krummholz section of the Continental Divide seen from the upper limits of the forest-tundra ecotone above INST AAR's Mountain Research Station.

The Indian Peaks section of the Continental Divide seen from the upper limits of the krummbolz, forest-tundra ecotone, above INSTAAR's Mountain Research Station.

The Indian Peaks section of the Continental Divide seen from the upper limits of the krummbolz, forest-tundra ecotone, above INSTAAR's Mountain Research Station.

The Indian Peaks krummholz section of the Continental Divide seen from the upper limits of the forest-tundra ecotone above INSTAAR's Mountain Research Station.

The Indian Peaks krummholz section of the Continental Divide seen from the upper limits of the forest-tundra ecotone above INSTAAR's Mountain Research Station.

The Pathophysiology of Chronic Hypoxia in Chickens

The debilitating effects of the hypoxia encountered at high altitude have been recognized for many hundreds of years, and have recently been the subject of numerous scientific investigations (8,9). Prolonged residence at high altitude leads to characteristic anatomic and physiological alterations (4,8), as well as special pathophysiological conditions such as "Brisket Disease" in cattle (3). The domestic fowl is particularly suited to studies of the pathophysiology of chronic hypoxia. Since it is the most sensitive of small homeotherms to hypoxia (1), effects may be rather severe at mountain altitudes.c Because of their ovipary, colonies of chickens can be maintained at reasonably high elevations by carrying out incubation (i.e., embryogenesis, the process most sensitive to hypoxia) at lesser and more suitable elevations. In 1955, a colony of Single Comb White Leghorn (SCWL) chickens was established at an elevation of 12,500 feet, at the White Mountain Research Station," with week-old chicks introduced from sea level. In 1956, a few of the chickens were sacrificed to determine the cause of a persistent mortality among adults. No evidence of contagious disease was encountered; however, there were obvious heart lesions and signs of chronic circulatory insufficiency. More detailed examinations were made in 1960, 1962, and 1964, and the results are reported herein.