This study examined whether the current generation of consumer-grade digital mobile computing technology, so called smartphone technology, is usable to perform and improve field data collection in the context of sustainable forest management. An electronic data acquisition system, based on a handheld smartphone device and desktop geographic information system (GIS), was developed. A proprietary timber cruise application and commercial mapping software were used with the smartphone/desktop GIS to record and process forest stand and geospatial data. Usability testing was carried out to measure workflow efficiency and system performance of the smartphone GIS compared to traditional paper-based methods. The smartphone GIS successfully met performance objectives and significantly increased workflow efficiencies by improving data transfer and processing times over conventional paper methods; however, use of the mobile device resulted in greater data entry errors, increased data collection times, and led to more equipment malfunctions than use of paper recording methods together with a GPS and digital camera. Overall, the prototype electronic data acquisition system was not reliable as a stand-alone solution solely responsible for collecting cruise data, but was found to be well suited for ad-hoc mapping of forest features.

Methane (CH4) is one of the most potent greenhouse gases and its increasing concentration in the Earth’s atmosphere is linked to today’s global warming. The types of land and land-use have an impact on net CH4 fluxes, e.g. wetlands are generally net CH4 emitters while upland forest soils are a sink for CH4. This project aimed to elucidate the effect of afforestation and reforestation on net CH4 fluxes and to determine the control of the CH4-oxidising bacteria (methanotrophs) on net CH4 flux rate. This was investigated using a combination of molecular (T-RFLP, cloning/sequencing, microarray) and activity-specific (PLFA-SIP) approaches. Several sites were selected to analyse soil methanotrophs under shrubs regenerating after a fire compared to a native mature forest (in New Zealand), and under bog, grass, heath, pine and birch vegetation (in Scotland). Furthermore, a simple bottom-up approach was applied to seasonal measurements of local net CH4 fluxes in Scotland. These were upscaled to annual values in order to estimate the contribution to the national CH4 budget for each habitat investigated. The effect on CH4 mitigation of the conversion of different types of non-forested habitat to forests was then estimated. Afforestation/reforestation was always found to induce net CH4 oxidation at rates much faster than previously estimated. This preliminary analysis suggests that heathland conversion to birch forest was beneficial in term of CH4 sinks but it also induced large and permanent losses of soil C. However, bog afforestation with pine trees can potentially neutralise the national CH4 emissions from non-forested areas, while preserving soil C stocks. This project also revealed that changes in net CH4 flux due to land-use changes were closely related to shifts in the structure of the methanotrophic community. The relative abundance of members of the USCα cluster (high-affinity methanotrophs) was a strong predictor of net CH4 fluxes. Finally, the sole presence of trees suggested a niche-specific adaptation of the methanotrophs, which may have been correlated to some of the soil characteristics.

No description available.

<p> Forest certification plays an important role in the forest products industry in Mississippi. Approximately 17% of the state&rsquo;s 19 million acres of forest land is certified under one of three major systems in the United States. More than two million acres are certified under Sustainable Forestry Initiative, more than one million acres are certified under American Tree Farm System and over 150,000 acres are certified under Forest Stewardship Council. </p><p> The goal of forest certification is sustainable use of all forest resources, from timber to clean water to recreation. This goal can only be achieved if nonindustrial private forest landowners, loggers, and forestry professionals all agree on the concepts each system espouses. </p><p> This project surveyed nonindustrial private landowners in Mississippi, members of the Mississippi Loggers Association, and members of the Mississippi Sustainable Forestry Initiative Implementation Committee, to test their levels of agreement on 12 different Likert Scales or sets of statements representing specific underlying concepts of forest certification. </p><p> The three groups generally agreed on most aspects of forest certification. There were some significant differences between the groups based on the distribution of responses, however the scale averages never differed by more than 0.7 indicating that while the differences were significant, overall they were still fairly close in their understanding of certification concepts. </p><p> There were a large number of non-industrial private landowners who were not aware of forest certification. This result has not changed since the last landowner study that was conducted in Mississippi regarding forest certification, almost 10 years ago.</p>

The establishment and intensive management of forests for the production of timber can have significant effects on the soil carbon dynamics. The establishment of forest on organic soils under grasslands may lead to substantial losses in soil carbon, due to the site preparation for the planting of trees and other disturbances. This is gradually compensated by carbon accumulation in tree biomass as the forest grows until clearfelling at maturity may initiate another substantial carbon loss. This study had two main aims. The first was to investigate the long-term effects of forest establishment on natural grassland as well as clearfelling and re-growth of the forest during second rotation, by looking at the changes in soil carbon stocks and soil carbon balance in a Sitka spruce (Picea sitchsensis) in Harwood (N. E. England). Secondly, to investigate the short-term effects of forest clearfelling on the fluxes of soil CO2, N2O and CH4 and on the environmental factors (soil temperature, water content and water table depth) affecting them. The fluxes were initially measured in two mature stands (40-years old) during one growth season. One of the two stands was subsequently clearfelled while the other was kept intact and fluxes were measured for a further ten months after clearfelling. The relationships between these fluxes and the environmental factors were also examined. The study also investigated the spatial variability of soil CO2 emissions using geostatistical approaches. The soil CO2 fluxes were measured with two methods, a closed dynamic chamber and a closed static chamber, giving the opportunity to compare their relative performance. A performance further investigation on this discrepancy between the two methods took place in lab experiments and on a soil monolith, excavated from the 40-year old stand and kept under controlled conditions in the greenhouse.

The aim of this project was to combine species distribution modelling (SDM) with the results of a molecular genetic diversity study to make suggestions for sites on which to locate genetic reserves. This work was complemented by a molecular genetic diversity and a forest management policy study, to examine the potential for in situ conservation of the crop wild relative species, Prunus avium. In order to identify the species distribution, the most widely available occurrence data were in the form of historical records, gathered from online repositories and herbaria. A selection of environmental variables were incorporated with occurrence records in the SDM software, MaxEnt, to estimate the existing and possible future distribution of this species. Different sampling methods and combinations of accessions were used to evaluate model performance. This work was supplemented by the use of microsatellite marker analysis, to identify genetic distance among samples collected, covering the species‘ range. Clear separation was found between the individuals from the south-eastern edge of the range, and all other European samples. The effect of management practices on the persistence of wild cherry in managed forests and the impact of conservation policy was also considered, using case studies from the UK and Belgium, interviews and grey literature. Results showed that the difficulties of obtaining reliable, unbiased data can be overcome, as long as these factors are considered in conservation planning. Suggestions are made for several potential reserve sites across Europe, in a variety of forested environments, with differing management priorities.

There are many documented environmental benefits to concentrating populations in cities. However, the impermeable nature of modern urban landscapes, which has been created by roads, buildings, and paved public spaces, has altered the natural cycle of water through today’s cities. As a result, a greater fraction of rainfall becomes runoff, creating stormwater pollution that degrades the very host environments needed to support city living. One attractive approach to urban stormwater management is the use of engineered and non-engineered vegetative systems to reduce the amount of rainfall that becomes runoff. When one considers the vast number of vegetative systems needed to bring about significant change, along with the variety of environmental niches in the urban landscape, it is clear that an array of “greening” strategies are needed. In turn, accurate performance data and models of these strategies are necessary to appropriately inform design and policy decisions. The research presented in this dissertation focuses on advancing the understanding, modeling, and design of three types of vegetated infrastructure with potential to address urban stormwater challenges: extensive green roofs, street trees, and vine canopies. The first research focus examines a nuance to a well-developed and well-studied technology: the extensive green roof. Nearly four years of environmental and runoff monitoring data from two full-scale extensive green roofs are used to determine how the time of year impacts hydrologic performance while considering the covariates of antecedent dry weather period, potential evapotranspiration and storm event size. Comparisons are made between thick and thin extensive green roof systems, and novel models are presented which account for seasonal variability. The second research focus evaluates the absorptive capacity of an existing type of urban vegetation: the street tree. In particular, this work looks at the permeability and infiltration capacity of the tree pit’s soil surface, which is often a controlling factor in the hydrologic performance of street trees. The resulting model links physical features of the tree pit to its ability to absorb water. Furthermore, the results indicate two simple, low-cost management strategies to improve urban stormwater capture via street trees. The third research focus explores the stormwater management potential for a new type of vegetated infrastructure: the horizontal vine canopy. Hydrologic performance data from sixteen vine canopies grown on a New York City rooftop are used to determine the capacity of the vines to retain stormwater, return water to the atmosphere via transpiration, and grow in the harsh rooftop conditions. Models and coefficients describing stormwater capture and plant transpiration are then presented and used to estimate the potential capacity of vine canopies to contribute to urban stormwater management. Exploration into new forms of vegetated infrastructure and facets of existing urban vegetation through the perspective of stormwater management has resulted in valuable findings and experimental methodologies. In several instances, these studies required new measuring equipment or sampling procedures, which were developed, validated, and made available for future research.

<p> In cities, microclimates are created by local mixtures of vegetation, constructed materials, vertical structure, and moisture, with significant consequences for human health, air quality, and resource use. Vegetation can moderate microclimates through evapotranspiration, however this function is dependent on local conditions so its effect may vary over space and time. This dissertation used hyperspectral and thermal remote sensing imagery to derive key observations of urban physical and biophysical properties and model urban microclimates across the megacity of Los Angeles. In Chapter 1, I used Multiple Endmember Spectral Mixture Analysis (MESMA) to map sub-pixel fractions of different vegetation types, as well as other types of urban cover, at 4 m and 18 m resolution over Santa Barbara, California (Wetherley et al., 2017). Fractional estimates correlated with validation fractions at both scales (mean R² = 0.84 at 4 m and R² = 0.76 at 18 m), with accuracy affected by image spatial resolution, endmember spatial resolution, and class spectral (dis)similarity. Accuracy was improved by using endmembers measured at multiple spatial resolutions, likely because they incorporated additional spectral variability that occurred across spatial scales. In Chapter 2, I applied this methodology to derive sub-pixel cover for the greater Los Angeles metropolitan area (4,466 km²) (Wetherley et al., 2018). Further improvement in quantifying sub-pixel vegetation types was achieved by modifying the MESMA shade parameter. Land surface temperature (LST), derived from thermal imagery, was used to model temperature change along vegetation fractional gradients, with slopes of LST change showing significant differences between trees and turfgrass (p &lt; 0.001). Expected per-pixel LST was derived from these gradients based on sub-pixel composition, and when compared to measured LST was found to deviate with a standard deviation of 3.5 &deg;C across the scene. These deviations were negatively related to irrigation and income, while building density was observed to affect tree LST more than it affected turfgrass LST. In Chapter 3, I used the map of Los Angeles landcover, along with data from LiDAR, GIS, and WRF climate variables, to parameterize an urban climate model (Surface Urban Energy and Water Balance Scheme: SUEWS) for 2,123 neighborhoods (each 1 km²) across Los Angeles. Modeled latent fluxes were correlated with remote sensing LST (R² = 0.39) collected over a period of 5 hours, with an overall diurnal pattern modified by irrigation timing. Spatial variability across the study area was related to local landcover, with albedo and vegetation fraction strongly influencing latent and sensible fluxes. A strong regional climatic gradient was observed to affect latent fluxes based on coastal proximity. Overall, this dissertation quantifies the key drivers of urban vegetation function in a large city, and further demonstrates the potential of hyperspectral and thermal imagery for observing city scale surface and microclimate variability.</p><p>

The United States Forest Service (USFS) bases their wildfire predictions on cloud-to-ground lightning flash density thresholds greater than 5 fl km-2. High flash densities and low precipitation are often emphasized with storms since they are associated with wildfire ignitions. Yet, greater flash rates tend to occur in the areas of greatest rainfall. This study focuses on 95 lightning-initiated wildfires in the western United States during the year of 2017. Lightning data provided by the National Lightning Detection Network (NLDN) were analyzed to determine which strike(s) likely caused each fire, as well as the strikes that did not. Detailed analysis of cloud-to-ground lightning characteristics and thunderstorm characteristics such as stroke density, precipitation rate, and 24-h storm-relative QPE totals are presented. Statistical analyses using a Wilcoxon-Mann Whitney rank sum test were performed to reveal differences between lightning flashes that ignite wildfires and those that do not. Results indicate multiple-stroke negative polarity cloud-to-ground flashes dominated the fire starts. In addition, wildfires were initiated in areas with low stroke densities. Based on these tentative findings, the USFS may need to revisit their methods for wildland fire prediction. Rain rates at the locations of fire starts were 8.03 mm h-1 less than those of non-fire starting flashes, while 24-h QPE totals were 5.28 mm less. These differences were found to be statistically significant. The results of this thesis will help expand the limited knowledge of operational lightning and wildfire meteorology. However, considerable additional research is needed. / A Thesis submitted to the Department of Earth, Ocean and Atmospheric Science in partial fulfillment of the requirements for the degree of Master of Science. / Spring Semester 2019. / March 28, 2019. / Climate Change, Flash Density, Lightning, Precipitation, United States Forest Service, Wildfires / Includes bibliographical references. / Henry Fuelberg, Professor Directing Thesis; Guosheng Liu, Committee Member; Mark Bourassa, Committee Member.

Includes bibliographical references