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Engineering Fire-Resilient Forests: Applications of Remote Sensing to Assess Aspen’s Distribution and Potential to Reduce Fire Hazard
No full textAcross the United States and globally, wildfire impacts to the built environment and ecosystems are driving increasing costs to society. There is no “one-size-fits-all” solution to reducing wildfire hazard for communities. The convergence of climate- and human-driven changes in wildfire activity requires collective action, innovative science and technology, and intentional management to mitigate the fire hazard. Addressing where and how we build, increasing wildland fire use and prescribed burning, and targeted fuels mitigation in hazard hotspots all play a significant role. However, traditional fuel treatments such as thinning or clear cutting often require revisitation to maintain positive benefits, creating persistent management challenges for communities. The expansion of “fire-resistant” species, such as quaking aspen (Populus tremuloides Michx.), has been proposed as one potential solution (or another “tool in the toolbox”) to reducing fire hazard in some regions, particularly in the Southern Rockies. Beyond the potential for aspen to reduce fire hazard, its ability to respond readily in post-disturbance landscapes provides critical forest resilience at a time when that has become more challenging due to compound disturbance interactions, a more fire-conducive climate, and increased area burned at high severity. However, more information is needed to understand where, how, and when aspen might moderate fire behavior, especially in the context of recent extreme fire activity. The growing widespread availability of remote sensing and geospatial data before, during, and after wildfires offers a promising avenue for elucidating answers to these questions and informing management decisions for this important forest species. In this dissertation, I present a series of studies which leverage remote sensing and geospatial analysis, environmental data science, statistical and machine learning and ecological principles to explore one potentially novel solution to wildfire hazard: the management of quaking aspen as a living fire break. To this end, we first developed new reproducible methods for mapping aspen at a higher spatial resolution than existing products, identifying an average patch size of 0.53 ha in the Southern Rockies. These new maps have major implications for management decision-making, as small patches may be disproportionally important for both maintaining and expanding existing aspen stands. Next, we demonstrate a novel application of satellite-derive fire radiative power (FRP) harmonized with burn severity, national wall-to-wall forest inventory, and geographic setting to elucidate the relationship between aspen forest composition and structure on fire intensity and severity in the Southern Rockies. We found that the proportion of forested area that is made up of aspen has a significant influence on both intensity and severity, with a -8.1% reduction for every unit increase in proportional aspen area. Further, we found that the influence of aspen dominance diminishes greatly under more extreme fire weather but may still offer a buffering effect where it co-occurs with other forest types, especially lodgepole. This demonstrates the capacity for aspen forests, especially in greater proportions, to reduce extreme fire behavior in some settings. Finally, we harmonized a suite of environmental data to map and prioritize firesheds in the Southern Rockies based on archetypes of aspen management now and into the future. This exercise identified 93 (5.4%) firesheds where aspen management for fire hazard reduction may be advantageous and successful and provides a rich database geared towards management prioritization and planning. Beyond this, we highlight other firesheds with different management scenarios.This overall effort contributes new data and ecological understanding of aspen’s distribution and potential to reduce fire hazard
Goose Herbivory Effects on Early-Stage Litter Decomposition in Coastal Alaskan Wetlands
No full textAims Herbivores create large differences in litter decomposition rates, but identifying how they do this can be difficult because they simultaneously influence both biotic and abiotic factors. In the Yukon-Kuskokwim (Y-K) River Delta in western Alaska, geese are dominant herbivores in wet-sedge meadows, where they create ‘grazing lawns’ that have nutrient-rich litter and an open habitat structure. To understand how geese affect decomposition, we tested the effects of litter quality and habitat type on litter decomposition over one year. Methods We performed a litter bag study in which we collected two litter types representing grazed and ungrazed vegetation conditions (high quality litter similar to grazed litter, and lower quality senesced, ungrazed litter), then incubated them in ‘grazing lawn’ and ungrazed meadows. Litter mass loss, carbon, nitrogen, cellulose and lignin content were measured after 3, 6, 9, and 52 weeks. We also monitored abiotic conditions (i.e., soil temperature, UV radiation, throughfall, and soil moisture content) in each habitat type. Results High-quality litter (lower lignin:N ratios) lost more mass than low-quality ungrazed litter over the whole study. However, at different times during the decomposition process, lower quality litter decomposed faster in grazed habitat, whereas higher quality litter decomposed faster in ungrazed habitat. This occurred despite abiotic conditions in grazed habitat that generally promote faster decomposition. Conclusion Results suggest that herbivore-induced increases in litter quality increase decomposition rates, and that the accumulation of the low-quality litter in ungrazed habitats is partly due to slow decomposition rates. While herbivores influence habitat conditions, the effects of habitat on decomposition differed across litter qualities, which suggests that other variables, such as differing microbial communities, play a role in decomposition processes
Herbivory in a Low Arctic Wetland Alters Intraspecific Plant Root Traits With Consequences for Carbon and Nitrogen Cycling
No full textHigh latitude wetlands are ecologically important ecosystems due to their large carbon (C) storage capacity and because they serve as breeding and nesting habitat for large populations of migratory birds. Goose herbivory in wetland meadows affects leaf chemical and morphological traits and also influences soil properties by increasing soil temperature and depositing faeces. Grazing-induced changes to above-ground traits and soil properties impact C cycling, but the influence of grazing on root-mediated C and nitrogen (N) cycling has not been explored. We investigated how goose herbivory in a low-Arctic coastal wetland in western Alaska affected root morphological, physiological and chemical traits of a dominant graminoid by assessing plant traits in ungrazed versus heavily grazed sedge meadows. We also performed a 11-week lab-based root incubation experiment to determine how grazing affects CO2-C efflux, the size and decay rate of the fast-cycling C pool (i.e. C with a mean residence time of days to weeks, determined via CO2-C efflux), and patterns of N mineralization during root decomposition. Goose grazing altered root chemical traits by increasing root N by 7%, cellulose by 12%, and ash content by 17%, indicating that grazing shifted root chemical traits towards a resource-acquisition strategy. Grazing did not alter root biomass, morphology or bulk C exudation. In our root incubation, soils that included the roots of grazed plants tended to exhibit greater CO2-C efflux than those containing ungrazed plant roots due to a larger fast-cycling C pool. Additionally, grazing-induced increases in soil temperature led to greater CO2-C efflux due to a faster decay rate of the fast-cycling C pool. Finally, compared with ungrazed roots, we found that the decomposition of grazed roots resulted in more N being transferred to root necromass from the surrounding soil, suggesting that microbial communities decomposing grazed roots immobilized N. Synthesis. Overall, our results indicate that goose grazing increased C-cycling rates by influencing soil environmental conditions and by altering the ecological strategy of grazed plants. In contrast, grazing decreased net N mineralization by promoting N immobilization. These results suggest that changing patterns and abundances of herbivores can have substantial effects on elemental cycles
Spectroradiometric Calibration Facilities at the NASA Ames Airborne Sensor Facility
No full textThe Airborne Sensor Facility (ASF) at NASA Ames Research Center maintains a suite of capabilities for the calibration of passive earth remote sensing instruments, focused on hyperspectral imaging devices operating in 350-2500 nm wavelength range, with additional thermal IR spectroradiometric resources extending to 14 microns. Hyperspectral instruments present challenges to characterization and calibration due to the large volume of data gathered in spatial and spectral dimensions. ASF uses techniques anticipating best practices developing in the IEEE standard p4001, while leveraging multiplex advantages for efficient data collection. ASF has developed facilities for the spatial, spectral and radiometric characterization of airborne hyperspectral imagers and is developing capabilities for stray light characterization. This presentation surveys these capabilities, using the facility instrument Pushbroom Imager for Cloud and Aerosol Research and Development (PICARD) as a case study. We will discuss the Multiple Field Collimator (MFC) system for spatial and spectral characterization, the integrating sphere sources for radiometric calibration and our developing stray light assessment methodologies. Results from PICARD’s calibration at both ASF and the Goddard Laser for Absolute Measurement of Radiance (GLAMR) lab will be compared to validate ASF’s spectral, radiometric, and stray light characterization capabilities
Developing a Consistent and Coordinated Response from the National Metrology Institutes’ Radiometry Community to the Needs of the Earth Remote Sensing Satellite-Observation Communities
No full textModern satellite-based Earth observation measurements demand long-term data records that span multiple missions with reduced uncertainties. SI-traceability and robust uncertainty analyses are key aspects to meeting these demanding requirements. In this presentation we report on the activities of the CCPR-WG-SP TG17, an international task force created within the Bureau International des Poids et Mesures (BIPM) to provide a consistent and coordinated response from the National Metrology Institute (NMI) radiometry community to the needs of the satellite-observation communities.
The BIPM is the international organization through which National Metrology Institutes work together on matters related to metrology. Within the BIPM, the Consultative Committee on Photometry and Radiometry (CCPR) conducts activities concerning measurement standards for photometric and radiometric quantities, development of absolute radiometry, and provides advice on matters concerned with radiometry and photometry. In 2024 the CCPR formed CCPR-WG-SP TG17 to provide a consistent and coordinated response from the NMI radiometry community to the needs of the satellite remote sensing communities.
This talk will report the activities of the CCPR-WG-SP TG17, with opportunity for stakeholders in the audience to provide input. Topics discussed will include relevant activities that are performed at multiple NMI’s, such as providing traceability to the SI for lunar irradiance measurements; activities that are currently available at one or a few NMI’s, such as SI-traceable, far-infrared measurements; and improving communication between the NMI community and the satellite community through discussions of SI-traceability, uncertainty analyses, and terminology
Fact Sheet for Parents: What You Need to Know About Alcohol
No full textThis fact sheet explains what alcohol is and why it is dangerous for kids and teens. It offers ideas for how parents can help prevent underage drinking and provides resources to help parents.
What Motives Influence Parents’ Commitment to Their Children’s Sport Participation in the United States?
No full textBackground: The public often places value on youth sport involvement in the United States due to its potential to foster positive outcomes for participants. Although sport parents are key socializers and provide access to appropriate participation opportunities for children, less is known about how their perceptions of their child’s motives influence their sport commitments. Purpose: Therefore, the purpose of the present study was to understand how parents’ perceptions of their child’s motives for sport participation were associated with time/travel sport commitments. Methods: Participants (N = 1250) were parents in the United States reporting on their child’s youth sport participation. Measures assessed their perceptions of their child’s motives for sport involvement, how many hours per week and months per year they engaged in sport, and how far they tended to drive to facilitate sport opportunities. Multiple regressions were utilized. Results: Analyses revealed that the number of months per year was positively predicted by motives for being physically healthy and spending time with friends. Similarly, being with friends was a positive predictor of the number of weekly hours spent in organized sport and having fun positively predicted the distance driven to participate. Motives for becoming more physically attractive negatively predicted time and travel commitments. Conclusions: Overall, the present study sheds light on how the ways parents perceive their children’s motivations for participating in youth sport influences parents’ commitment to facilitating sport participation opportunities for their children
Exploring Biostimulant Efficacy Under Limited Fertilizer and Water in Utah\u27s Watermelon Production
No full textThe western U.S. has recently experienced some of the driest conditions on record, and Utah has been in a multi-year drought (2019-2023) that affected the agricultural sector, including vegetable producers. While vegetables are not a primary agricultural crop in Utah, they are still an important part of the horticultural economy with 763 farms growing 6,138 acres. As the fourth largest acreage vegetable crop in Utah (almost 10% of the acreage) watermelon and related crops in the gourd family Cucurbitaceae (nearly 36% of total vegetable acreage) are important to vegetable growers. Watermelon is a water-intensive crop and requires an adequate supply of water for good yield and fruit quality and is very sensitive to water stress. An additional challenge is that watermelons need access to adequate nutrients for proper growth and high yields, which has become more difficult with the recent rise in fertilizer prices
Eutrophication
No full textEutrophication refers to the ecological state of a water body after excessive nutrient pollution. The external introduction of nutrients (primarily nitrogen and phosphorus) accelerates the growth and reproduction of plants, algae, and microbes. This fact sheet explains where eutrophication comes from, its impacts, how it is treated, and what you can do to help restore and protect our lakes, rivers, and oceans
Chemical analyses of grass samples
No full textResults of chemical analyses of grass samples collected in the foothills of the Henry Mountains, south-central Utah, in the fall of 2021