Crises unwasted: How policy entrepreneurs linked forest biomass to energy security in Colorado, 1998-2013

Eckhoff, Mike Colorado State University 2014 해외박사(DDOD)

Colorado's forests are facing threats from wildfires, insect and disease epidemics and human encroachment. At the same time, Coloradans are facing energy security problems from fossil fuel price volatility, unintended consequences from continued fossil fuel dependence, problematic alternative, non-renewable fuel promotions and a struggling renewable energy industry. Subsequently, natural resources managers in Colorado are facing two imposing challenges simultaneously: 1) the need to restore forest health and 2) to manage energy resources sustainably, equitably and with public safety in mind. Policy entrepreneurs invested in forest energy found ways to link forest health emergencies to energy security crises. This dissertation is a study that explores how that link was forged and what happened in Colorado as result, looking at the actions taken by the four major federal land management agencies (U.S. Forest Service, Bureau of Land Management, National Park Service and the U.S Fish and Wildlife Service). This study also traced briefly how the State of Colorado responded to these crises, too. First, this study qualitatively surveyed literature in the forest history and policy arenas and energy history and policy arenas to chart how prior events led to current conditions. Media articles were tabulated and coded to quantitatively gauge how salient their respective issues were over time. Using Multiple Streams Theory, policy windows were identified. Second, the Punctuated Equilibrium Theory was applied to the emerging forest energy policy arena during the time frame identified by the policy windows. Finally, interviews and meetings were held with employees at the federal, regional/state and local levels and with members of state government to determine how the increased saliency of forest and energy issues translated to forest energy policy actions on the ground in Colorado. This dissertation concludes that federal land management agencies took greater interest and made significant efforts to promote forest energy in Colorado between the years 2000 and 2013. This increased interest resulted in increased funding, regulation and project development and implementation in the state. However, while activity increased, opportunity for additional actions remains. Coloradans would be wise to foster additional public-private initiatives and work to promote forest energy among large groups of proximal forest communities. Inevitably, as fossil fuel supplies decrease and prices increase, Colorado, along with the rest of the country, will in part be forced to return back to its "roots" and Dukert's notion of "the future behind us.".

The intersection of agriculture, Latinas/os, and higher education in the land grant system: A mixed methods study

Archibeque-Engle, Shannon L Colorado State University 2015 해외박사(DDOD)

From government reports and academic journals to popular media there is a call for more educated agriculturalists. Latinas/os have long been instrumental in United States' agriculture and yet similar numbers of Latinas/os are not studying agricultural sciences at land grant universities. The mission of land grant universities is to provide access to education, especially agricultural education. Given the changing demographics of the United States, if land grant universities are to address our nation's need for educated agriculturalists, Latinas/os must be included as part of the solution. This study provides universities, particularly land grant institutions, a portion of the data and analyses necessary to identity how to both recruit and successfully graduate people prepared to lead as professional agriculturalists. This study deconstructs the intersection of agriculture, Latinas/os, and higher education. This transformative convergent parallel mixed methods study examines the learning environment of agricultural higher education from a Critical perspective. This examination is conducted through three distinct studies and is organized in a manner similar to the chronological order an undergraduate student would encounter a College of Agricultural Sciences. That is, what do students first encounter in terms of physical artifacts, what are the lived experiences for students, and finally what are the student success outcomes in the College of Agricultural Sciences. The first segment of this dissertation focuses on what a student first encounters upon entering a College of Agricultural Sciences. Physical artifacts present in educational settings make visible the values of the institution. Such messages signal the institution's desire for a culturally inclusive and supportive environment. Given the land grant mission of inclusive education, the labor heritage of agriculture, and the saliency of stereotype threat in creating an inclusive learning environment, critically assessing the equity climate of departments of animal sciences in land grant universities is overdue. This study utilizes Banning et al.'s 2008 taxonomy based on visual ethnography methodology to interpret the equity climate of three departments of animal sciences at land grant institutions to answer the critical question: who is welcome? The systematic coding and thematic analysis reveal exclusive learning environments clearly communicated by the physical artifacts present. The second portion of this dissertation addresses the lived experiences of students. While there has been a focus on recruiting Latinas/os and others to study agricultural sciences, there has not been an examination of the lived experience of Latinas/os currently studying agricultural sciences in college. The purpose of this narrative study was to describe the lived experience of six Latina undergraduate students studying in a College of Agricultural Sciences at a Predominantly White Land Grant Institution. The thematic analysis of the transcribed interviews yielded three distinct themes, namely, Overt Exclusion , Nepantlera, and Intersectionality through the saliency of agricultural identity. Recommendations for inclusive agricultural education environments were voiced by the participants, providing us a path forward to fully include and support Latina students in the agricultural academy. The third segment of this dissertation study focused on undergraduate student success. Given the financial constraints of most institutions, it is important that we are strategic in our programming to support an ever more diverse undergraduate population. This study offers a rigorous and systematic approach to quantitatively assess programmatic needs in three segments: an analysis of the demographic representation of the state, an analysis of historic opportunity gaps (1990 through 2014), and an analysis of recent undergraduate student success utilizing predictive logistic regression models. Using Colorado State University (CSU) as a case study for this systematic assessment, CSU was found to not represent the state it serves, Colorado. Further, statistically significant opportunity gaps were found for gender, Pell eligibility, first generation status, residency, and minority students. Finally, the first year retention, four year graduation rate, and six year graduation rate predictive models provided evidence for program investment to support first generation, minority, and resident students. Of note, non-minority students were found to be 1.78 times more likely to graduate in four years than were minority students. Minority students were 53 percent less likely to graduate then majority students in six years. First generation students were less likely than non-first generation students to graduate in six years and non-residents were more likely to graduate than residents of the state within the six year time frame.

Introduction and management of Myxobolus cerebralis -resistant rainbow trout in Colorado

Fetherman, Eric R Colorado State University 2013 해외박사(DDOD)

Myxobolus cerebralis, the pathogen responsible for salmonid whirling disease, was unintentionally introduced to Colorado in the late-1980s. Following its introduction, M. cerebralis caused significant declines in wild rainbow trout (Oncorhynchus mykiss) populations across the state. Hundreds of thousands of M. cerebralis-susceptible rainbow trout were stocked into Colorado's waters in an effort to reduce these population level declines, however, rainbow trout populations continued to disappear. In the early-2000s, a hatchery-derived, M. cerebralis-resistant rainbow trout strain, the German Rainbow (GR) strain, was discovered at a Bavarian hatchery in Germany. The GR strain was imported into Colorado and crossed with the Colorado River Rainbow (CRR) strain, a wild rainbow trout strain that had been widely stocked in Colorado and comprised many naturally reproducing wild rainbow trout fisheries prior to the introduction of M. cerebralis. Crosses of the GR and CRR were rigorously evaluated in laboratory experiments, and the first filial generational cross between the two strains (termed the H×C) was found to exhibit resistance characteristics similar to those of the GR strain. In addition, the H×C is capable of attaining critical swimming velocities similar to those of the CRR strain. Laboratory results suggested that the H×C was the best candidate for reintroducing rainbow trout in areas with a high prevalence of M. cerebralis; however, its utility needed to be evaluated in a natural setting. In the first of two introduction experiments conducted as part of my dissertation research, the H×C was introduced to the upper Colorado River downstream of Windy Gap Reservoir in Grand County, Colorado. The objectives of the introduction were to examine the abundance, survival and growth of the stocked H×C population. In addition, the age-0 rainbow trout genetic composition in the upper Colorado River was examined to determine if H×Cs had contributed offspring to the age-0 population. I also evaluated whether these offspring displayed increased resistance and survival characteristics compared to their wild CRR counterparts. In the second introduction experiment, conducted in the Cache la Poudre River in Larimer County, Colorado, brown trout (Salmo trutta) were removed from one of two rainbow trout introduction locations with the objective of determining whether brown trout removal would increase the survival and retention of GR-cross fish. Radio Frequency Identification (RFID) passive integrated transponder (PIT) tags and antennas were used to passively estimate survival and to track movements made by PIT-tagged fish (both stocked rainbow trout and wild brown trout) in reaches where brown trout had (removal reach; 1.0 km) or had not (control reach; 1.3 km) been removed. Additionally, two crosses of rainbow trout were stocked for this experiment, the H×C, and a cross between the GR and Harrison Lake rainbow trout strain (originating from Harrison Lake, Montana; termed the H×H); H×H fish had been stocked in Colorado rivers prior to this experiment, but their performance in the wild had not been rigorously evaluated. Apparent survival for the H×C during the primary study period did not differ for fish within the control or removal reaches; however, apparent survival of H×C fish that moved out of a reach (upstream or downstream) was much lower than that of H×C fish within a reach. Apparent survival for the H×H during the primary study period was higher for fish in the control reach than fish in the removal reach; similar to the H×Cs, survival was much lower for H×H fish that moved out of reach than fish within a reach. Brown trout survival was higher in the control reach than it was in the removal reach during the primary study period. The H×C exhibited similar movement probabilities (out of the reach) in both the control and removal reaches, suggesting that the presence of brown trout did not affect H×C movement. The H×H, however, exhibited higher movement probabilities out of the control reach than they did out of the removal reach, suggesting that the presence of brown trout affected H×H movement. Brown trout exhibited similar net movement probabilities into both reaches during the primary study period, and secondary movement patterns suggest that the brown trout population was in a state of equilibrium in both reaches, following initial movements into the reaches, during the primary study period. (Abstract shortened by UMI.).

Public values for restoring natural ecosystems: Investigation into non-market values of anadromous fish and wildfire management

Kaval, Pamela Colorado State University 2004 해외박사(DDOD)

This dissertation is composed of three papers, each using surveys as an aid to understanding public values. The public values on which I focus are related to restoring natural ecosystems: the Lower Snake River in Washington and Colorado Forests. The first paper, "Recreational Benefits of Removing the Lower Snake River Dams: A Test of Scope for Contingent Visitation Behavior," examines whether respondent recreation behavior would change if four dams were removed from the Lower Snake River. Two contingent visitation behaviors were tested: whether to visit the Snake River if dams are removed and frequency of visitation for two groups of respondents; the general public and Snake River anglers. The second and third papers focus on Colorado forest ecosystems. Colorado forests are currently experiencing high intensity wildfires as a result of a century of wildfire suppression. Colorado residents living within the wildland urban interface were surveyed to find out how they feel about various fire management prescriptions that may aid in restoring Colorado forest ecosystem health. The survey focused on two types of questions: contingent valuation willingness-to-pay questions and ladder of life well-being evaluation questions. The first of the two fire papers is titled "Analysis of Public Perspectives of Wild and Prescribed Fires in Colorado." In this paper, I analyzed willingness-to-pay information for three fire management techniques: prescribed fires, fire suppression, and fire prevention. The second fire paper is titled "Using GIS to Investigate the Relationship between Stakeholder Opinion about Wildfire and Landscape Context." This paper builds upon the first by adding spatial modeling to the context. GIS maps were used to create new fire danger variables, and included wildfire locations, slope, and vegetation. Additional variables created from these maps include wildfire distance from homes and vegetative fire danger of homes in their immediate vicinity (100 feet) and extended vicinity (1 mile). These three papers showed that respondents are knowledgeable about their environments and are, in general, in support of restoring some natural ecosystems. They not only support these issues, but they are also willing-to-pay for them, thereby indirectly indicating importance of restoring natural ecosystems to the United States public.

Black bear ecology and human-bear interactions in an urban system

Baruch-Mordo, Sharon Colorado State University 2012 해외박사(DDOD)

The goal of my research was to address American black bear (<italic> Ursus americanus;</italic> hereafter bears) ecology in and around the city of Aspen, Colorado. In Chapter 1, I assessed the degree of bear synanthropy, i.e., dependency on anthropogenic resources and subsequent changes to behavior and population dynamics, and its relationship to individual and environmental covariates to test hypotheses about irreversible and fluctuating synanthropy. Synanthropy is likely a continuum that varies among individuals and across time, although in a management context bears are often perceived dichotomously as synanthropic or not, and the degree of synanthropy with its spatial and temporal fluctuations are rarely considered. Understanding such patterns is especially important for managing urban bears and for resolving conflicts with people. I used six years of detailed GPS location and activity data that were collected for bears in Aspen. I modeled space use (home range size, its overlap with human development, and mean human density within home range) and daily activity patterns as a function of individual and environmental covariates, estimated survival using known-fate models and modeled its relationship to covariates, and summarized reproduction in years of good and poor natural food production. In Chapter 2, I experimentally evaluated efficacy of education and enforcement in changing human behavior to better secure bear attractants. Evidence-based decision-making is critical for implementing management actions, especially for human-bear conflicts. Wildlife managers are recognizing that long-term solutions should include altering human behaviors, and public education and enforcement of wildlife-related laws are two management actions frequently implemented, but with little empirical evidence evaluating their success. I conducted three experiments in Aspen to evaluate: 1) on-site education in communal dwellings and construction sites, 2) Bear Aware educational campaign in residential neighborhoods, and 3) elevated law enforcement at two levels in the core business area. I measured human behaviors as the response including: violation of local wildlife ordinances, garbage availability to bears, and change in use of bear-resistance refuse containers. As implemented, I found little support for education, or enforcement in the form of daily patrolling in changing human behavior, but found more support for proactive enforcement, i.e., dispensing warning notices. More broadly I demonstrated the value of gathering evidence before and after implementing conservation actions, and the dangers of measuring responses in the absence of detailed knowledge of the system (e.g., natural food production, bear movements, etc.). I recommended development of more effective educational methods, application of proactive enforcement, and continued evaluation of tools by directly measuring change in human behavior. I provided empirical evidence adding to the conservation managers' toolbox, informing policy makers, and promoting solutions to human-wildlife conflicts. In Chapter 3, I demonstrated the application of patch-selection models to examine how changes in energetic costs and benefits that result from management targeting bears and people can influence bear foraging decisions. I used patch selection models (a dynamic, state-dependent modeling approach based on foraging theory) to assess how benefit reduction and cost increase affect bear foraging decisions. I applied the patch selection models to the urban system of Aspen, in which bears forage in human-dominated patches and conflicts are common. I used survival as a fitness currency and body fat reserves as a state variable. I incrementally reduced availability of anthropogenic foods and increased energetic costs of movement in response to aversive management to search for thresholds resulting in avoidance of human-dominated patches. Benefit reduction ≥60% in both human-dominated patches resulted in bears of almost all states avoiding those patches. Cost increases achieving similar results exceeded 1300% in the urban patch and 400% in the urban-interface patch, and are unrealistic to implement. Given modeling results and that control strategies targeting wildlife are unpopular with constituencies, I suggested allocating management resources to strategies that reduce availability of anthropogenic food. (Abstract shortened by UMI.).

Sampling strategies for forest aerial detection survey in Colorado

Ha, Anh Quang Colorado State University 2015 해외박사(DDOD)

Aerial detection survey (ADS) has been commonly employed in forest surveys in the United States for detecting forest damage and monitoring forest health. In Colorado, ADS by USDA Forest Service has conducted annual 100% census of government forested land for more than 20 years with the goal of achieving information about forest damage due to different causal agents and disorders. Sketchmapping has been commonly employed in ADS with the goal of detecting and documenting on maps mortality, defoliation and other visible forest change from aircraft. At medium and large scale, sketchmapping is a suitable technique for forest monitoring that provides valuable information in forest health. This dissertation deals with data of forest area damaged by five causal agents mountain pine beetle, spruce beetle, western spruce budworm, pin engraver, and Douglas fir beetle and two disorders subalpine fir mortality and sudden aspen decline. The combined areas damaged by all causes were also considered. Data were downloaded from ADS in Colorado from 1994 to 2013 as polygon shapefiles with associated information such as causal agents or disorders, area damaged, and type of forest. The goal of my dissertation was to identify an appropriate sampling strategies to archive good estimates of total area damaged, to decrease survey cost, and to increase safety by reducing the amount of flights. To approach this goal, four sample designs for estimating total area damaged caused by various causal agent were evaluated: simple random sampling, stratified random sampling, probability proportional to size, and non-alignment systematic sampling. A GIS layer of 150 transects covering Colorado's forestlands was developed and represented the sample unit for my study. Each transect was 3.2 km wide and 625 km long and was numbered from 1 to 150 from south to north. Each sample design was evaluated using eight sample sizes (10, 15, 20, 25,30, 35, 50, and 70) and applied to the seven damages and the combined damaged area. The statistical properties were evaluated to determine the optimal sample design for estimating area damaged caused by different causal agents. The spatio-temporal characteristics of area damaged that influence precision and accuracy of estimate were considered. Most of the damaged forest areas by single causal agents and disorders showed aggregated spatial patterns; whereas the combined damaged areas were uniformly distributed across the landscape. A loss plus cost function was employed to determine the optimal sample size for each sample design and analyzed for the cost advantage of alternative sample designs. We found that stratified random sampling was the most optimal sample design by producing the highest percentage of unbiased estimates of total area damaged and the smallest variances. The next best sampling designs were simple random sampling and probability proportional to size. The non-alignment systematic sampling was the worst for estimating total area damaged both for individual causal agents and disorders and all causal agents combined. The optimal sample size varied by sample design and causal agents and disorders as well as the level of confidence. Optimal sample size increased with increasing variability in the population and as the desired level of confidence increased. Larger samples were required to simultaneously provide estimates for multiple causal agents and disorder with reasonable levels of precision when compared to a single causal agent. Stratified random sampling was the most cost effective when compared with other sample designs. For example, the cost advantage of stratified sampling over random sampling for estimating the damage from subalpine-fir mortality was $85,000 per year. In contrast, PPS sampling had a cost disadvantage of -$13,000 per year when compared with simple random sampling and -$95,000 per year when compared with stratified sampling for estimating the total damage from all causal agents combined at the 0.95 level of confidence.

Wheat stem sawfly oviposition preference and survivorship on winter wheat and downy brome

Altilmisani, Nuha Mustafa Colorado State University ProQuest Dissertations & 2016 해외박사(DDOD)

The wheat stem sawfly Cephus cinctus Norton (Hymenoptera: Cephidae) is a major economic pest of wheat in the United States can decrease the yield and grain quality. Wheat stem sawfly infests both cultivated and uncultivated host plants. It is important to understand the oviposition behavior and host selection of the female wheat stem sawfly. Wheat stem sawfly selects the most suitable host for oviposition. The host selection behavior and oviposition preference of wheat stem sawfly for downy brome (Bromus tectorum L.) grass and winter wheat (Triticum aestivum L.) in Colorado was studied to assess whether downy brome is affecting the presence and infestation levels of wheat stem sawfly in winter wheat in northeastern Colorado. Infestation rates and larval development of the wheat stem sawfly were studied for two years (2013 and 2014) at seven commercial winter wheat fields and eight nearby downy brome sites in northeastern Colorado. Stem samples of each plant species were randomly collected per site weekly and sweep samples of sawfly adults were taken after adult emergence. Infestation rate in winter wheat was 12 to nearly 14 times higher than in downy brome throughout the two year survey. Larval mortality was twice as high in downy brome than in winter wheat over the two year survey. More adults were collected in May from winter wheat than from downy brome in the two year survey. Wheat stem sawfly females preferred to oviposit in wheat plants over downy brome. Female oviposition behavior influences by different host quality cues such stem height and diameter, volatile production, and growth stage. Host selection and oviposition preference by wheat stem sawfly females were studied with a combination of greenhouse choice and no-choice tests using a susceptible (hollow stem) winter wheat variety 'Byrd', a resistant (solid stem) winter wheat variety 'Bearpaw', and downy brome. Female sawflies in the no-choice tests laid similar numbers of eggs in Byrd and Bearpaw plants irrespective of growth stage, which were approximately 2.5 times the number of eggs laid on downy brome. Similarly, when given a choice, females laid similar numbers of eggs on Byrd and Bearpaw, but nearly twice as many eggs on either of these two cultivars than on downy brome. Females preferred to oviposit in larger diameter plant stems. However, stem height did not affect female preference for plants at growth stage Zadoks 49, but females prefered taller stems at growth stages Zadoks 32 and 60. Larval survivorship was lowest in the solid stem Bearpaw and was highest in downy brome and the hollow-stem Byrd. Hollow stem wheat had the highest larval survivorship. Female wheat stem sawflies use chemical cues from plants to identify a suitable host for oviposition. A Y-tube bioassay was developed to evaluate female wheat stem sawfly behavior in response to an airflow that passed over winter wheat cultivars and downy brome. Choice and no-choice tests were conducted with three host plants: wheat cultivars Byrd and Bearpaw and downy brome at three different growth stages: Zadoks 32, 49, and 60. Adult females were attracted to wheat cultivars Byrd and Bearpaw over downy brome at all growth stages. Downy brome was least preferred (31.82%) by female wheat stem sawfly in choice test of Bearpaw vs. downy brome at Zadoks 32 while it was equally preferred (49.21%) in the choice test of 'Byrd vs. downy brome' at growth stage of Zadoks 60. The female's response speed did not differ when given a choice between the two wheat cultivars Byrd and Bearpaw. However, females were faster in making a choice (100% ? 86% females made fast choice) toward each of wheat cultivars over downy brome in the choice tests of Bearpaw vs. downy brome and Byrd vs. downy brome at all growth stages.

Modeling landscape dynamics and environmental association for spruce mortality

Suksavate, Warong Colorado State University 2016 해외박사(DDOD)

This study addresses important issues related to mortality of spruce species (Picea sp.) associate with outbreaks of spruce beetle (Dendroctonus rufipennis Kirby) by 1) modeling large scale landscape dynamics of spruce mortality associated with long-term climate in Colorado and Alaska; 2) modeling environmental association between spruce mortality and small scale environmental covariates including climatic factors. In the first chapter, we review the ecology and etiology of spruce mortality in Colorado. In the second chapter, we evaluate landscape dynamics of spruce mortality at the regional scale of Colorado and Alaska. We used climate transition matrices (CTMs) as a method to assess the influence of climate on spruce forest extent and mortality. We quantify the probabilities of observing spruce forest, spruce mortality, and the mismatches between probabilities for the presence of host and mortality as indicated by differential effects. All values were calculated to populate elements of CTMs. The polynomial functions of ordinary regressive model and spatial autoregressive model were implemented to represent the association between climate zones and the responses. The results show us that there are influences of long-term precipitation and temperature on both probabilities. Presence of spruce forest in Colorado is associated with high precipitation at moderately low temperatures while probability of spruce mortality has a similar association. High probability of observing spruce forest in Alaska is associated with low to moderate precipitation while the probabilities of observing spruce mortality are positively associated with high precipitation at warmer temperatures. From the differential effects, there are mismatches of responses between host and mortality implying the advantageous of host associate with moderate temperatures and high precipitation in Colorado while healthy forest is found in the moderately low temperature and moderate precipitation in Alaska. In the third chapter, we describe associations between stand scale environmental conditions and spruce mortality. We modeled the association using zero-and-one inflated beta regression model based on hierarchical Bayesian framework. Two-stage Bernoulli logistic models were applied to indicate the occurrence of the extreme values represent presence and absence of mortality; continuous proportional responses were then addressed by beta regressive model. Multivariate Gaussian latent process was included in the function to express the exponential spatial errors term. The results indicate that spatial distribution of the occurrence and intensity of spruce mortality were both associated with the local stand covariates of temperature zone, precipitation zone, class of stand structure level, relative dominance class, and size class. The colder temperature zones have highly negative effects on both the probability of mortality occurrence and the probability of full mortality occurrence, while the warmer temperature zone is positively associated with the presence of full mortality. The results also indicate that stand characteristics are important factors associated with mortality. Mortality occurrence is positively associated with single-story stands with medium to large size classes. The higher-complexity stand structures have highly positive associations with the probability of entire stand mortality, while medium to high dominance classes have negative effects on full mortality. The largest size class and the highest dominance class have negative associations with the proportion of partial mortality.

Evaluating the ASCE standardized Penman-Monteith equation and developing crop coefficients of alfalfa using a weighing lysimeter in southeast Colorado

Al Wahaibi, Hamdan Salem Colorado State University 2011 해외박사(DDOD)

Quantification and efficient irrigation application of crop water requirements are potential ways for water resources conservation and sustainability. Reference evapotranspiration (ETref) is a very important variable in the quantification of crop water requirement. The ASCE standardized ETref equation has been recommended recently for calculating ETref. However it has not been tested under Colorado conditions. In addition, crop coefficients (Kc) for use with the ASCE standardized reference ET equation have not been developed in Colorado. Crop coefficients that have been used by the Colorado Division of Water Resources were estimated from Kimberly, Idaho and Bushland, Texas even though the growing conditions such as soil, elevation, climate and environmental factors in Colorado are different than in Kimberly and Bushland. They were developed using reference ET equations other than the ASCE standardized PM ETref equation and later they were adapted for use with the ASCE standardized PM ETref equation (Allen et al., 2007). The objectives of this study were to test the performance of the ASCE standardized ETref equation for calculating alfalfa reference ET under southeast Colorado conditions and to develop compatible crop coefficients of alfalfa that apply to the region. A corollary objective was to determine if the full version of the Penman-Monteith equation could better match measured alfalfa ET from the lysimeter when reference conditions were satisfied. A precise weighing lysimeter was used to measure alfalfa ET and to develop crop coefficients of alfalfa at Rocky Ford in Southeast Colorado. The lysimeter was filled with a 3 m x 3 m x 2.4 m undisturbed soil monolith and alfalfa (Genoa variety) was planted in the lysimeter and in 4 ha of surrounding field in August 2007. Alfalfa was harvested four times in each of the 2008, 2009 and 2010 growing seasons. ETref was calculated using the hourly ASCE standardized PM ETrs (standardized reference evapotranspiration for tall reference crop) and full version Penman-Monteith equations using climate data from an automatic weather station installed at the lysimeter site. Crop coefficients of alfalfa were calculated by dividing daily measured ET from the lysimeter by the corresponding daily ASCE standardized reference ET. Season total alfalfa ET from the lysimeter ranged from 1179 mm to 1455 mm. Maximum daily water use of alfalfa was around 14.4 mm/day in 2010 season due to relatively high maximum temperature, high solar radiation and high wind speed. Average daily ET for 2008, 2009 and 2010 was 5.7 mm/day, 6.0 mm/day and 6.9 mm/day, respectively. Hourly calculated ETrs values agreed well with measured ET from the lysimeter whenever alfalfa was under reference conditions (height of at least 50 cm and no soil water stress). Residuals between calculated ETrs and measured lysimeter ET increased as air temperature increased and as relative humidity decreased. Greater residuals were obtained when 80 % of the footprint length was not in the field. During some periods, there was lack of adequate fetch and this contributed to greater differences between the ASCE standardized ETrs and lysimeter ET. Good agreement between ASCE standardized ETrs and lysimeter ET was obtained when at least 80% of the ET flux footprint was inside the alfalfa field. The alfalfa growth stage, climate, precipitation and soil water content were major factors that shaped the crop coefficient curves. The first cutting cycle, which had slower growth due to cooler weather, had smaller crop coefficients, whereas later cutting cycles with rapid growth had larger crop coefficients. The maximum crop coefficients were below 1.2 in 2008 (water stressed) and at or slightly above 1.2 in 2009 and 2010. The Kcr values greater than 1.0 were due to ETc from the lysimeter being greater than ETrs from ASCE standardized PM. Periods when alfalfa in the lysimeter was taller than alfalfa in the immediate surroundings and when the canopy extended outside the lysimeter boundary (3 m x 3 m) contributed to Kcr values greater than 1.0. Precipitation interception by the alfalfa canopy increased evaporation and caused outliers in the crop coefficient values. Crop coefficients were greatly affected by soil water content. A reduction in the alfalfa crop coefficients was observed at the end of some cutting cycles that coincided with reductions in soil water content. The average leaf area index (LAI) at a height of 50 cm was 4.34 m 2/m2 and there was a high correlation between LAI and alfalfa height with R2 of 0.94, but the relationships were not the same as suggested by Allen et al. (1994). ETref values calculated by the full version of the Penman-Monteith equation deviated more from the lysimeter ET compared to the ASCE standardized ETref equation. Full version of Penman Monteith showed very good agreement with ASCE standardized ET. Using the full version of the Penman-Monteith equation did not improve agreement with lysimeter ET at reference conditions.

Observations of atmospheric reactive nitrogen species and nitrogen deposition in the Rocky Mountains

Benedict, Katherine B Colorado State University 2012 해외박사(DDOD)

Many national parks are experiencing increased nitrogen deposition due to increased emissions of reactive nitrogen, especially in the western United States. Excess nitrogen deposition can adversely impact ecosystem function, in some cases leading to degradation of water quality and forest decline. One region of particular interest is the Rocky Mountains, where large increases in wet deposition of oxidized and reduced nitrogeN·have been observed in recent decades. Here we present results from several field campaigns in Rocky Mountain National Park (RMNP) and a field campaign in Grand Teton National Park (GTNP) focused on identifying important nitrogen deposition pathways and factors that are contributing to nitrogen deposition. To understand nitrogen deposition in RMNP we focused on understanding the spatial variability of reactive nitrogen concentrations across the state of Colorado. We observed large gradients in the reactive nitrogen species that reflected the different source regions across the state. In eastern Colorado, home to large agricultural operations, we observed high concentrations of ammonia and ammonium. Concentrations decreased moving westward toward the Front Range urban corridor and the Rocky Mountains. Concentrations of nitric acid, an important oxidation product of nitrogen oxides emissions, were highest in the Front Range urban corridor. Concentrations of gaseous ammonia and nitric acid were much lower in RMNP than at the sites to the east. Particle concentrations of ammonium and nitrate were generally lower in RMNP as well; however, concentration gradients were sometimes not as strong as for the gas phase compounds. Wet deposition of ammonium and nitrate were the two largest reactive nitrogen deposition pathways in RMNP, yielding inputs of 1.97 kg N·ha<super> -1</super> or 56% of total nitrogen deposition. Dry deposition of ammonia and wet deposition of organic nitrogen were the next most important deposition pathways; together they accounted for 40% (1.37 kg N·ha<super>-1</super>) of annual total nitrogen deposition. These two pathways are of special interest because they have not historically been monitored as part of regional deposition budgets. The remaining deposition pathways (dry deposition of nitric acid, and PM_2.5 ammonium, nitrate, and organic nitrogen) accounted for approximately 3% of total nitrogen deposition. In GTNP there was a strong gradient in ammonia concentrations, with higher average concentrations to the west (0.6 µg/m<super>3</super>) and lower average concentrations to the east (0.3 µg/m<super>3</super>), consistent with the presence of large agricultural operations west of the park. Concentrations of nitric acid, nitrate, and ammonium did not exhibit any clear spatial trends. Ammonia concentrations were higher at GTNP than at RMNP while PM_2.5 nitrate and ammonium concentrations were similar in the two regions. Average nitric acid concentrations were similar between the two parks as well, with the exception of one high elevation GTNP site where higher concentrations were observed. Wet deposition of ammonium and dry deposition of ammonia were the largest reactive nitrogen deposition pathways in GTNP followed by wet deposition of nitrate and wet deposition of organic nitrogen. Previous ecological assessments have led to the establishment of a critical load for wet deposition of inorganic nitrogen to RMNP and GTNP. A critical load is the maximum level of nitrogen input that can be sustained by an ecosystem without irreversible damage like loss of biodiversity. Our observations reveal that the critical load is currently being exceeded in both RMNP and GTNP. It is important to recognize that substantial additional inputs of reactive nitrogen are occurring in both parks through dry deposition of ammonia and wet deposition of organic nitrogen. Neither pathway is currently considered in the U.S. critical load framework. In both RMNP and GTNP organic nitrogen was an important component of deposition. (Abstract shortened by UMI.).