Theses and Dissertations at Montana State University (MSU)
Permanent URI for this collectionhttps://scholarworks.montana.edu/handle/1/733
Browse
20 results
Filters
Settings
Search Results
Item Sierran mixed conifer forest wildfires: a biodiversity comparison between active and passive timber land management(Montana State University - Bozeman, College of Agriculture, 2019) Dalby, Caitlin M.; Chairperson, Graduate Committee: William KleindlThe mixed conifer forests of the Northern Sierras have great value in their biodiversity. Timber land management in this region varies by land owner and their objectives, including timber harvest and conservation. An increase in annual wildfires each year indicates a need to understand how different silvicultural strategies before and after fires affect the overall ecosystem biodiversity. Ecosystem functions and services can be affected by many factors involving anthropogenic activities in combination with fires. The aim of this study was to determine to what degree active (private timber company) and passive (United States Forest Service) management after a wildfire may affect plant biodiversity, and to compare those silvicultural approaches to active and passive pre-fire management. The study takes place within the vicinity of the 2012 Chips fire burn scar in Plumas County, California. Using tree canopy and plant species percent cover, in addition to presence and absence data, within frames and nested frames along 50 meter transects, statistical analyses revealed little significant difference between active and passive management. Analysis from data collected in this study concluded that tree canopy cover is significantly different under active post-fire management than under passive post-fire management and pre-fire conditions. There was not a significant difference in understory biodiversity (richness and evenness) among the four treatments. Dissimilarity in plant species composition was significant among the burned and unburned treatments, as well as between the two differently managed burned treatments. While the treatments were significantly dissimilar, there was not enough data collected to account for the high degree of variability seen in the data and so further data collection and analyses across multiple spatial and temporal scales would give better insight into the differences in biodiversity between treatments.Item Understanding hydrogeomorphic influences on stream network denitrification and temperature dynamics(Montana State University - Bozeman, College of Agriculture, 2020) Carlson, Samuel Paul; Chairperson, Graduate Committee: Geoffrey PooleThe removal of nitrate from stream networks through the process of denitrification is an important component of local and regional nutrient cycles, but the controls on stream network denitrification rates remain poorly understood. Previous work has demonstrated general effects of stream channel size and nitrate loading rates on network-scale denitrification rates, but has been unable to elucidate connections between the complex environmental template of streams, and resulting denitrification rates. Understanding links between land use and management practices, physical characteristics of streams, and stream denitrification rates is critical to interpreting observed patterns of nitrate in freshwater systems and forming holistic management strategies for reducing the negative effects of elevated nitrate concentrations. To address these critical uncertainties, I developed a stream network simulation model that incorporates the effects of whole-stream aerobic respiration on biotic denitrification demand. This model is applied to a small, subalpine stream network under scenarios designed to explore: 1) the implications of temperature-controlled, network scale patterns of respiration rates on the distribution and overall magnitude of stream network denitrification, and 2) the effect of logging-induced channel simplification on whole network denitrification rates. The first analysis is complimented by an evaluation of controls on stream temperature across this network, revealing the spatially and temporally variable influence of in-network lakes on stream temperatures. Results from the first analysis suggest that reach- and network-scale denitrification rates are strongly influenced by respiration rate and temperature when nitrate supplies are high relative to removal rates, indicating an increased contribution of lower, warmer streams to whole-network denitrification. The second analysis reveals that historical logging has caused a ~30% loss of stream network denitrification capacity, which is manifested as a corresponding reduction in whole-network denitrification rates when nitrate supplies are not limiting. In sum, this work emphasizes the diverse set of factors that influence reach- and watershed-scale biogeochemical characteristics and processes, and suggests that land management actions which influence stream morphology may also alter stream denitrification rates.Item The influence of post-wildfire logging on forb and pollinator communities and forb reproductive sucess, Gallatin National Forest, Montana(Montana State University - Bozeman, College of Letters & Science, 2016) Heil, Laura Jean; Chairperson, Graduate Committee: Laura BurklePollinators are in decline worldwide, and these declines have implications for flowering plants and their reproduction, given that 80% of flowering plants depend on insects for pollination. One potential contributor to pollinator species' declines is shifts in disturbance regimes, such as increased severity and frequency. Wildfires are essential natural disturbances that are important drivers of forest biodiversity in the western U.S., and there is often pressure to respond to wildfire with management including post-wildfire logging. This management strategy involves the removal of dead trees for economic value immediately following wildfire. Thus, is expected that post-wildfire logging has additional impacts on forest communities compared to non-salvage logging, and that it impacts forb and pollinator communities. Several studies have examined the short-term responses of forb and pollinator communities to wildfire and non-salvage logging individually, and one study examined their combined effects. However, no studies have examined the long-term effects of post-wildfire logging, on forb and pollinator communities and on forb reproduction. My research addresses these gaps in knowledge and asks: 1) how do floral and bee communities respond to post-wildfire logging and how do their responses differ between two different-aged fires, and 2) how does post-wildfire logging influence forb reproduction and pollen limitation of reproduction in an older wildfire? In the more recent fire, floral and bee density and species richness were higher in logged than unlogged areas. By contrast, in the older fire, forb and bee communities were similar between logged and unlogged areas. Unexpectedly, we found large inter- and intra-annual variation in the effects of post-wildfire logging. Lastly, in the older fire, there were no effects of post-wildfire logging on forb reproduction, but plants were pollen limited in unlogged areas. This suggests that plants in unlogged areas are able to augment their reproductive output with supplemental pollen resources, but plants in logged areas cannot. Together, these results suggest that post-wildfire logging is beneficial for forbs and pollinators in the short-term, and these positive effects depend on time of growing season and sampling year. However, post-wildfire logging may be detrimental for forb reproduction in the long-term.Item Ecology of Merriam's turkeys in relation to burned and logged areas in southeastern Montana(Montana State University - Bozeman, College of Letters & Science, 1993) Thompson, William L.Item The Relationships of wood debris to juvenile salmonid production and microhabitat selection in small southeast Alaska streams(Montana State University - Bozeman, College of Letters & Science, 1984) Dolloff, Charles AndrewItem The formulation of a technique for finding an optimal 'skidding' road layout(Montana State University - Bozeman, College of Engineering, 1968) Carter, Michael RichardItem Grizzly bear use of habitats modified by timber management(Montana State University - Bozeman, College of Letters & Science, 1992) Waller, John StevenItem Breeding bird populations in logged and unlogged forest stands in southwestern Montana(Montana State University - Bozeman, College of Letters & Science, 1993) Mulqueen, Kathleen ElizabethItem Model implementation and image data compression in a decision support system(Montana State University - Bozeman, College of Engineering, 1997) Wang, XiaobeiItem Mono-cable logging system with intermediate tension control : computer simulation(Montana State University - Bozeman, College of Engineering, 1988) Turk, Albert VincentA cooperative research project with the USDA-Forest Service has shown the need for a mono-cable logging system with intermediate tension control as an alternative to road construction in the logging area. Intermediate control sheaves will be required to maintain optimum tension throughout long distances and large elevation changes. Preliminary designs have shown the need to model the system to demonstrate the system's feasability. A series of FORTRAN programs were written to simulate this system, building first upon single span solutions, with the eventual program including the capability of simulating the changes in tension of a system of up to 100 connected spans with as many as 200 loads traversing the system. The individual sheaves along the system path can be modeled as either control or idler sheaves. The solution of the necessary equations required the use of iterative solutions. Comparison was made of the Newton-Raphson method and Brown's method for the solution of a set of two non-linear equations with two unknowns. The model satisfies the simulation needs of the system. It allows the monitoring of tension, differential tension across sheaves, and changes in cable length required within each span. The program showed the feasibility of the system and gives direction for future modifications of the model to more closely simulate the actual situation. The program will provide a solid foundation for current and future work in this area and shows a valid procedure for future modeling.