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Search indexed NASA NTRS and DOE OSTI research on propulsion, heat transfer, battery materials and energy systems. Follow report and document links to the original sources.

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At least 19 records
All sourcesNASA NTRSDOE OSTI
DOE OSTI2026

AmeriFlux FLUXNET-1F CA-Na1 New Brunswick - 1967 Balsam Fir - Nashwaak Lake Site 01 (Mature balsam fir forest)

This is the AmeriFlux Management Project (AMP) created FLUXNET-1F version of the carbon flux data for the site CA-Na1 New Brunswick - 1967 Balsam Fir - Nashwaak Lake Site 01 (Mature balsam fir forest). This is the FLUXNET version of the carbon flux data for the site CA-Na1 New Brunswick - 1967 Balsam Fir - Nashwaak Lake Site 01 (Mature balsam fir forest) produced by applying the standard ONEFlux (1F) software. Site Description - immature balsam fir forest

Bourque, Charles P.-A.↗
DOE OSTI2023

Range-wide population assessments for subalpine fir indicate widespread disturbance-driven decline

Subalpine forests in western North America are threatened by rapid climate change, increased activity by endemic and exotic insects and diseases, and changing wildfire regimes. The interactive effects of these stressors have resulted in pronounced population declines in many subalpine tree species; however, a systematic assessment of the status and trends of subalpine forests is lacking. Subalpine fir (Abies lasiocarpa) is a widespread species across the western United States, with documented population declines in many parts of its distribution. Here we use subalpine fir as an initial leverage point to build a more complete understanding of subalpine forest baseline conditions and responses to environmental change. Specifically, we leverage the USDA Forest Service Forest Inventory and Analysis (FIA) database to (1) ask how subalpine fir populations are changing across the species’ distribution in the western US, (2) assess the drivers of recent subalpine fir population trends, and (3) explore whether those changes imply generalized species-wide and/or system-wide decline. We found that subalpine fir abundance and basal area are declining concurrently across ~ 62% of the species’ distribution, and increasing across ~ 19%. Range-wide, we estimated 25.02 ± 2.74 % subalpine fir mortality between 2000 and 2009 and 2010–2019 FIA inventory periods, with higher mortality concentrated in the eastern Oregon Cascades, central Idaho, and parts of southern Colorado. High regeneration density did not predict positive population trajectories, which were instead associated with higher rates of adult recruitment. While the importance of different mortality agents varied substantially between ecoregions, 83.4% of total range-wide mortality was related to fire or biological disturbance. Declining subalpine fir basal area coincided with declines in the basal area of other co-occurring tree species in 39% of subalpine forest area, and with increases in conspecific basal area in 22% of forest area. Fire disturbance was the single largest cause of subalpine fir mortality; however, even where subalpine fir fire mortality was high, mortality among other species was primarily caused by insects. In conclusion, our results suggest that subalpine fir declines across large portions of the western United States are driven by forest disturbance, and that declines in subalpine fir populations may be indicative of negative change in subalpine forest systems broadly.

54 ENVIRONMENTAL SCIENCES↗
DOE OSTI2023

Woodland wildfire enables fungal colonization of encroaching Douglas‐fir

Abstract Self‐reinforcing differences in fire frequency help closed‐canopy forests, which resist fire, and open woodlands, which naturally burn often, to co‐occur stably at landscape scales. Forest tree seedlings, which could otherwise encroach and overgrow woodlands, are killed by regular fire, yet fire has other effects that may also influence these feedbacks. In particular, many forest trees require symbiotic ectomycorrhizal fungi in order to establish. By restructuring soil fungal communities, fire might affect the availability of symbionts or the potential for symbiont sharing between encroaching trees and woodland vegetation. To investigate this possibility, we performed a soil bioassay experiment using inoculum from burned and unburned oak woodlands and Douglas‐fir forests. We examined how fire, ecosystem type, and neighboring heterospecific seedlings affect fungal root community assembly of Douglas‐firs and oaks. We asked whether heterospecific seedlings facilitated fungal colonization of seedling roots in non‐native soil, and if so, whether fire influenced this interaction. External fungal colonization of oak roots was more influenced by fire and ecosystem type than by the presence of a Douglas‐fir, and oaks increased the likelihood that Douglas‐fir roots would be colonized by fungi in oak woodland soil. Yet, fire increased colonization of Douglas‐fir in oak soil, diminishing the otherwise crucial role played by oak facilitation. Fire also strengthened the positive effect of Douglas‐firs on oak root‐associated fungal diversity in Douglas‐fir forest soil. Prior work shows that fire supports woodland ecosystems by stemming recruitment of encroaching seedlings. Here, we find evidence that it may contrastingly reduce fungal limitation of invasive seedling growth and establishment, otherwise relieved only by facilitation. Future work can investigate how these opposing effects might contribute to the net impact of changes in fire regime on landcover stability. Read the free Plain Language Summary for this article on the Journal blog.

54 ENVIRONMENTAL SCIENCES↗
NASA NTRS2016

Fir Decline and Mortality in the Southern Siberian Mountains

Increased dieback and mortality of dark needle conifer (DNC) stands (composed of fir (Abies sibirica),Siberian pine (Pinus sibirica) and spruce (Picea obovata)) were documented in Russia during recent decades. Here we analyzed spatial and temporal patterns of fir decline and mortality in the southern Siberian Mountains based on satellite, in situ and dendrochronological data. The studied stands are located within the boundary between DNC taiga to the north and forest-steppe to the south. Fir decline and mortality were observed to originate where topographic features contributed to maximal water-stress risk, i.e., steep (18 deg to 25 deg), convex, south-facing slopes with a shallow well-drained root zone. Fir regeneration survived droughts and increased stem radial growth, while upper canopy trees died. Tree ring width (TRW) growth negatively correlated with vapor pressure deficit (VPD), drought index and occurrence of late frosts, and positively with soil water content. Previous year growth conditions (i.e., drought index, VPD, soil water anomalies) have a high impact on current TRW (r = 0.60 to 0.74). Fir mortality was induced by increased water stress and severe droughts (as a primary factor) in synergy with bark-beetles and fungi attacks (as secondary factors). Dendrochronology data indicated that fir mortality is a periodic process. In a future climate with increased aridity and drought frequency, fir (and Siberian pine) may disappear from portions of its current range (primarily within the boundary with the forest- steppe) and is likely to be replaced by drought-tolerant species such as Pinus sylvestris and Larix sibirica.

conifer mortality↗
NASA NTRS2016

Fir Decline and Mortality in the Southern Siberian Mountains

Increased dieback and mortality of dark needle conifer (DNC) stands (composed of fir (Abies sibirica),Siberian pine (Pinus sibirica) and spruce (Picea obovata))were documented in Russia during recent decades. Here we analyzed spatial and temporal patterns of fir decline and mortality in the southern Siberian Mountains based on satellite, in situ and dendrochronological data. The studied stands are located within the boundary between DNC taiga to the north and forest-steppe to the south. Fir decline and mortality were observed to originate where topographic features contributed to maximal water-stress risk, i.e., steep (1825),convex, south-facing slopes with a shallow well-drained root zone. Fir regeneration survived droughts and increased stem radial growth, while upper canopy trees died. Tree ring width(TRW) growth negatively correlated with vapor pressure deficit (VPD), drought index and occurrence of late frosts, and positively with soil water content. Previous year growth conditions (i.e., drought index, VPD, soil water anomalies)have a high impact on current TRW (r 0.600.74). Fir mortality was induced by increased water stress and severe droughts (as a primary factor) in synergy with bark-beetles and fungi attacks (as secondary factors). Dendrochronology data indicated that fir mortality is a periodic process. In a future climate with increased aridity and drought frequency, fir (and Siberian pine) may disappear from portions of its current range (primarily within the boundary with the forest steppe)and is likely to be replaced by drought-tolerant species such as Pinus sylvestris and Larix sibirica.

Kharuk, Viacheslav I.↗
NASA NTRS1990

HI and FIR emission from S0 galaxies

A large body of work has accumulated in recent years which throws into disarray the traditional assumption that S0 systems are inert, non-starforming galaxies with uniform, old stellar populations. The copious 21-cm data have been recently reviewed and assessed by Wardle and Knapp (1986). This work showed that roughly a third of the several hundred observed S0's contain detectable amounts of neutral hydrogen (HI). More recently, Pogge and Eskridge (1987) have shown that a significant fraction of HI-rich systems also exhibit H alpha emission. Thronson et al. (1989) report detection of CO line emission from two thirds of the S0's in their sample. Both of these last papers, however, report on fairly small data sets (approx. 20 objects each). From co-added Infrared Astronomy Satellite (IRAS) data, Knapp et al. (1989) report that roughly two thirds of a sample of several hundred S0's are detected at 60 and 100 microns. Work by Bally and Thronson (1989) and Walsh et al. (1989) has shown that, while a large number of S0's follow a relation between radio continuum and far infrared radiation (FIR) emission similar to that found for spirals, significant numbers of both radio-bright, and FIR-bright S0's exist. Clearly, a large number of factors are involved in determining the state of the interstellar medium in S0 galaxies. The class is probably heterogeneous, suggesting that large data samples are required to sort out various sorts of objects. The 21 cm and FIR samples are the two largest currently available. It is therefore of interest to compare the two and see where this leads. The following results are already clear: HI and FIR flux data can be used to isolate strong candidates for systems which have gained their HI gas via accretion; a rough power-law relationship exists for galaxies which are undergoing relatively normal star-forming activity; a heterogeneous class of galaxies with strong FIR emission compared to their HI emission exists. Further work is required to determine the various physical processes responsible for this last class.

Eskridge, Paul B.↗
NASA NTRS1990

FIR statistics of paired galaxies

Much progress has been made in understanding the effects of interaction on galaxies (see reviews in this volume by Heckman and Kennicutt). Evidence for enhanced emission from galaxies in pairs first emerged in the radio (Sulentic 1976) and optical (Larson and Tinsley 1978) domains. Results in the far infrared (FIR) lagged behind until the advent of the Infrared Astronomy Satellite (IRAS). The last five years have seen numerous FIR studies of optical and IR selected samples of interacting galaxies (e.g., Cutri and McAlary 1985; Joseph and Wright 1985; Kennicutt et al. 1987; Haynes and Herter 1988). Despite all of this work, there are still contradictory ideas about the level and, even, the reality of an FIR enhancement in interacting galaxies. Much of the confusion originates in differences between the galaxy samples that were studied (i.e., optical morphology and redshift coverage). Here, the authors report on a study of the FIR detection properties for a large sample of interacting galaxies and a matching control sample. They focus on the distance independent detection fraction (DF) statistics of the sample. The results prove useful in interpreting the previously published work. A clarification of the phenomenology provides valuable clues about the physics of the FIR enhancement in galaxies.

Sulentic, Jack W.↗
DOE OSTI2021

Tree Diversity, Site Index, and Carbon Storage Decrease With Aridity in Douglas-Fir Forests in Western Canada

Forests are important for biodiversity, timber production and carbon accumulation, but these ecosystem services may be impacted by climate change. Field data collected from individual forest types occurring across a climatic gradient can contribute to forecasting these consequences. We examined how changes in temperature, precipitation and aridity affect ecosystem services in 23 mature Douglas-fir (Pseudotsuga menziesii) forests in nine climatic regions across a 900 km gradient in British Columbia, Canada. Using Canadian National Forest Inventory methodology, we assessed richness and diversity of plant functional groups, site index, and above- and below-ground carbon stocks. As aridity increased, ecosystem-level tree species richness declined on average from four to one species, Douglas-fir site index declined from 30 to 15 m, and ecosystem carbon storage decreased from 565 to 222 Mg ha –1 . Tree species richness was positively and herb species richness negatively correlated with carbon storage. Carbon storage by ecosystem compartment was largest in aboveground live tree biomass, declining in the following order: mineral soils > coarse woody debris and dead standing trees > forest floor > small and fine woody debris > understory plants. Mineral soil carbon at depths of 0-15 cm, 15-35 cm, and 35-55 cm increased with increasing mean annual precipitation and decreasing aridity. Our results indicate that as aridity increases and precipitation decreases, tree species richness, site index and carbon storage in existing Douglas-fir forests declines. However, assisted or natural migration of Douglas-fir into more humid regions could be associated with more diverse, productive, carbon-rich forests. This study informs carbon stock vulnerability and provides empirical data essential for carbon stock forecasts.

54 ENVIRONMENTAL SCIENCES↗
DOE OSTI2023

AmeriFlux FLUXNET-1F CA-Ca1 British Columbia - 1949 Douglas-fir stand

This is the AmeriFlux Management Project (AMP) created FLUXNET-1F version of the carbon flux data for the site CA-Ca1 British Columbia - 1949 Douglas-fir stand. This is the FLUXNET version of the carbon flux data for the site CA-Ca1 British Columbia - 1949 Douglas-fir stand produced by applying the standard ONEFlux (1F) software. Site Description - 1949 Douglas-fir stand; Tower Type 20" triangular tower; Latitude/Longitude 49.86725N 125.33360W (GPS survey, 2003. Coordinates updated/corrected May, 2006); Elevation 320 m; North-east facing terrain, 5-10 deg slope; Mean Air Temp. 8.3 °C* ; Mean Annual Precipitation 1461 mm * ; Date Operations Began June 1997 ; Frequency of EC Measurements 20.83 Hz; Frequency of Other Met. Sensors 1 - 4 sec, year round ; Soil Respiration Measurements 30 min., automated soil respiration system in 2000, periodically during growing season using portable system in 2002 ; * 1998-2001 averages from the 1948 Douglas-fir stand meteorological tower

Black, T. Andrew↗
NASA NTRS1988

A Landsat Thematic Mapper investigation of the geobotanical relationships in the northern spruce-fir forest, Mt. Moosilauke, New Hampshire

This investigation, in the northern spruce-fir forest at Mt. Moosilauke, NH, indicates that Landsat TM data can be used to distinguish between and map major vegetation zones. Principal components analysis can be used to reduce the dimensionality of the TM data; and in this simpler spectral space, it is easier to visualize the discrimination between major vegetation zones: the northern hardwoods zone, spruce-fir zone, fir zone, and alpine tundra zone. The moisture stress index highlights areas of heavy forest damage (fir waves), but does not correlate with low levels of damage in the mixed, background forest at Mt. Moosilauke. Care must be taken to avoid confusion between high-elevation climatically-stressed vegetation (normal krummholz forest) and damaged lower elevation forests, both of which have similar TM5/TM4 ratio values.

Torcoletti, Paul J.↗
NASA NTRS1991

Stratospheric spectroscopy with the far-infrared spectrometer (FIRS-2) - Overview and recent results

The Smithsonian Astrophysical Observatory's program of balloon-borne stratospheric spectroscopic measurements is described, including instrumentation, recent scientific results, and future plans. The design and operation of the FIRS-2 far-infrared spectrometer is discussed. The current status of our efforts to recover mixing-ratio profiles with about 1 percent precision is presented. Representative recent results are shown giving mixing-ratio profiles from 20 to 50 km, selected from the suite HOCl, HCl, HF, NO2, N2O, HNO3, OH, HO2, H2O2, H2O (and isotopes), O2 (and isotopes), O3 (and isotopes), and CO2 (and isotopes). The utility of O2 and CO2 spectral lines for information on view angle or temperature and pressure is discussed. Future plans are mentioned, including the use of FIRS-2 on a balloon platform for UARS correlative measurements, the use of FIRS-2 on the NASA DC-8 platform for polar measurements, and the potential benefits of a FIRS instrument on a Shuttle platform.

Traub, Wesley A.↗
DOE OSTI2023

AmeriFlux FLUXNET-1F CA-Ca2 British Columbia - Clearcut Douglas-fir stand (harvested winter 1999/2000)

This is the AmeriFlux Management Project (AMP) created FLUXNET-1F version of the carbon flux data for the site CA-Ca2 British Columbia - Clearcut Douglas-fir stand (harvested winter 1999/2000). This is the FLUXNET version of the carbon flux data for the site CA-Ca2 British Columbia - Clearcut Douglas-fir stand (harvested winter 1999/2000) produced by applying the standard ONEFlux (1F) software. Site Description - Tower Type: 10" triangular tower; Latitude/Longitude 49.87048N -125.29087W (GPS survey, 2003. Coordinates updated/corrected May, 2006); Elevation approx. 180m; Mean Air Temp. (for the growing season) 8.3 C*; Mean Annual Precipitation 1461 mm *; Date Operations Began August 2000; Frequency of EC Measurements 7.7 Hz (2000 ­ 2001), 20 Hz (2002); Frequency of Other Met. Sensors 4 sec, year round; Soil Respiration Measurements Periodically during growing season using portable system in 2002; * 1998-2001 averages from the 1948 Douglas-fir stand meteorological tower

Black, T. Andrew↗
DOE OSTI2026

AmeriFlux FLUXNET-1F CA-Ca3 British Columbia - Pole sapling Douglas-fir stand

This is the AmeriFlux Management Project (AMP) created FLUXNET-1F version of the carbon flux data for the site CA-Ca3 British Columbia - Pole sapling Douglas-fir stand. This is the FLUXNET version of the carbon flux data for the site CA-Ca3 British Columbia - Pole sapling Douglas-fir stand produced by applying the standard ONEFlux (1F) software. Site Description - Site: 1988 Harvested Douglas Fir (Pole-sapling); Tower Type 10" triangular tower; Latitude/Longitude 49.53462N -124.90044W (GPS survey, 2003. Coordinates updated/corrected May, 2006); Elevation approx. 170 m; Mean Air Temp. (for the growing season) 9.7 C *; Mean Annual Precipitation 1179 mm *; Date Operations Began: September 2001; Frequency of EC Measurements 20 Hz; Frequency of Other Met. Sensors 4 sec, year round; Soil Respiration Measurements Periodically during growing season using portable system in 2002; * 30-yr climate normals from the Comox Airport

Black, T. Andrew [University of British Columbia, ↗
NASA NTRS1986

Sun angle, view angle, and background effects on spectral response of simulated balsam fir canopies

An experiment is described that examines the effects of solar zenith angle and background reflectance on the composite scene reflectance of small balsam fir (Abies balsamea (L.) Mill.) arranged in different densities. In this study, the shape, density, and, consequently, the needle area index and phytomass of the canopies, as well as the background reflectance, were controlled. The effects of sun angle, view angle, and background reflectance on the multispectral response of small balsam fir trees were significant. Regression models relating spectral vegetation indices (i.e., normalized difference (ND) and greenness (GR) to phytomass) showed very poor relationships for balsam fir canopies with a grass background. However, strong linear relationships were found for ND and GR with phytomass for a background that simulated the reflectance of snow. Changing solar zenith angle significantly affected the models relating ND to phytomass for the snow background, but was not significant in the model relating GR to phytomass for the snow background

Ranson, K. J.↗
NASA NTRS1991

The relation between FIR and H I emission in galaxies

This project explored the relationship between the global far-infrared and neutral hydrogen (H I) emission from galaxies, based on data from the Infrared Astronomy Satellite (IRAS) and published radio data. 100 and 60 micron IRAS fluxes were used to establish a temperature corrected measure of the cold dust emission, and H I fluxes were drawn from the literature with the greatest possible consistency. The degree of correlation between the FIR and H I fluxes was found to be better than in previous studies, comparable to the correlation previously found between FIR and CO fluxes. The improvement was obtained largely by (1) separating 'stripped' from 'unstripped' galaxies, and (2) using compatible sources of H I data. Stripping occurs in clusters of galaxies and is probably caused by ram-pressure effects as a galaxy travels through the intergalactic medium. Our results suggest that stripped galaxies have had their outer-disk gas removed (approximately 80% of their total H I) while retaining most of their 100-micron-emitting dust. This strongly shifts the ratio of their 100-micron-to-H I fluxes. The second problem, arising from diverse sources of data, arises because differing telescopes and observational techniques give rise to substantial disagreement in the measured H I flux, and this degrades the correlation of the FIR and H I fluxes.

Schneider, Stephen E.↗
NASA NTRS1998

Alignment and Polarization Sensitivity Study for the Cassini-Composite InfraRed Spectrometer (CIRS) Far InfraRed (FIR) Interferometer

The Composite InfraRed Spectrometer (CIRS) instrument flying on the Cassini spacecraft to Saturn is a cryogenic spectrometer with far-infrared (FIR) and mid-infrared (MIR) channels. The CIRS FIR channel is a polarizing interferometer that contains three polarizing grid components. These components are an input polarizer, a polarizing beamsplitter, and an output polarizer/analyzer. They consist of a 1.5 micron thick mylar substrate with 2 gm wide copper wires, with 2 gm spacing (4 micron pitch) photolithographically deposited on the substrate. This paper details the polarization sensitivity studies performed on the output polarizer/analyzer, and the alignment sensitivity studies performed on the input polarizer and beamsplitter components in the FIR interferometer.

Crooke, Julie A.↗
NASA NTRS1998

Alignment and Polarization Sensitivity Study on the Cassini: CIRS FIR Interferometer

The Composite InfraRed Spectrometer (CIRS) instrument flying on the Cassini spacecraft to Saturn is a cryogenic spectrometer with far-infrared (FIR) and mid-infrared (MIR) channels. The CIRS FIR channel is a polarizing interferometer that contains three polarizing grid components. These components are an input polarizer, a polarizing beamsplitter, and an output polarizer/analyzer. They consist of a 1.5 micron thick mylar substrate with 2 microns wide copper wires, with 2 microns spacing (4 microns pitch) photolithographically deposited on the substrate. This paper details the alignment sensitivity studies performed on the polarizing beamsplitter, and the polarization sensitivity studies performed on all three polarizing components in the FIR interferometer.

Crooke, Julie↗