Arboricultural work is inherently dangerous, with more serious injuries and fatalities than most other professions. Safety standards exist in some jurisdictions, but it is unclear how many standards exist, how they compare to one another, and whether (and how many) jurisdictions share standards. To establish a baseline understanding of these issues, my objectives were to (i) develop a database of existing standards, (ii) identify the most frequently occurring safety topics and (iii) describe similarities and differences in safety topics among standards from different countries. I worked with a variety of contacts and traditional university library resources to identify, obtain, analyze, and compare arboricultural safety standards from around the world. I established a database of standards and found that various types of standards exist among countries: most countries used locally developed standards and industry standards were the most common types of standards because of industry professional’s expertise in arboricultural work safety matters. I analyzed the contents of 4 areas of arboricultural work categories in standards: General safety requirements (GSR), personal protective equipment (PPE), chainsaw (CS) and tree climbing (TC). GSR and PPE categories had the most proportion of common safety topics as compared to CS and TC. I identified most common safety topics in all 4 categories which shed light onto some of the areas of safety practices which are commonly recognized as important, while least common safety topics suggest areas of arboricultural work that may or may not be useful in future revisions of standards. There were 7 groups of countries most similar in the types of standards which they use, suggesting that countries can influence one another in adopting safety practices and that there are regional and international cooperation between countries in developing standards. My findings can be used by safety committees around the world in developing standards, as well as for the ISA’s International Safety Committee (ISC) to initiate an international safety standard. This study is novel and a stepping-stone for future research in evaluating the effectiveness of standards in reducing arboricultural work incident rates.

The future of Vermont’s 1.8 million hectares (4.5 million acres) of forest habitat will be largely determined by the decisions of family forest owners, who collectively own 60% of the state’s forested land. To promote management for wildlife habitat, government agencies and non-governmental partnerships provide technical and financial support to family forest owners in the form of conservation assistance programs. In Chapter 1, I qualitatively compared the efficacy of two types of conservation assistance programs available in Vermont: traditional programs offered through the Natural Resources Conservation Service, and a simplified, accelerated program offered through a non-governmental partnership called Woods, Wildlife, and Warblers. By conducting interviews with 20 Vermont family forest owners, I identified common motivation and barrier themes and compared these themes across programs using the Transtheoretical Model’s Stages of Change. Most motivations and barriers were described by landowners across all Stages of Change, but two motivations (professional recommendations and straightforward applications) and one barrier (independent forest management values) varied by either Stage of Change, program type, or both. I used the findings from the interviews to develop a mail survey, which was used to quantify patterns regarding motivations and barriers towards three habitat conservation actions: 1) arranging for a forestry professional to walk the land, 2) applying for cost-share funds, and 3) making a patch cut. The results from this survey, which was sent to 2,122 randomly selected Vermont family forest owners and had a cooperation rate of 38%, are presented in Chapter 2. Using logistic regression models, I identified multiple significant motivations or barriers for each of the three actions. Additionally, I used contingency tables to compare respondents’ levels of agreement for these motivations and barriers – as well as their level of trust for various information sources – with their Stage of Change. Overall, levels of agreement varied significantly across one or more Stages of Change for all motivations and barriers, and trustworthiness varied for 13 out of 14 information sources. Across both chapters, I provide recommendations to increase program efficacy with an emphasis on program attributes and tailored messaging.

The Allideghi Wildlife Reserve in the Amibara District of Afar Regional State, Ethiopia, has international significance for harboring endangered Grevy's Zebra and other wildlife dependent on grasslands. The reserve is increasingly used by pastoral people and their herds. Impacts of livestock on native vegetation include direct effects of grazing and indirect effects from livestock-facilitated dispersal of an invasive plant, Prosopis juliflora. The main research objective was to determine effects of pastoralism and vegetation change on prospects for sustaining the Allideghi Wildlife Reserve as grassland habitat for Grevy's Zebra. Methods included use of driving surveys to quantify resource use by herbivores, vegetation analysis, and engagement with local people. Resource-use patterns of livestock across the Allideghi grassland were often positively affected by proximity of water, while that for wild ungulates was often negatively affected by proximity of people. Livestock concentration at a major borehole has created a large piosphere with concomitant reductions in herbaceous standing-crop, productivity, and species richness; plant species have shifted from grasses to forbs in severely grazed sites. Vegetation further from the borehole was resilient in response to moderate grazing pressure in terms of species composition and productivity. Since being introduced at a nearby commercial plantation in the 1970s, P. juliflora has been dispersed to the Allideghi Wildlife Reserve via livestock; cattle, sheep, and goats eat the pods and deposit seeds in manure at settlements and favored foraging areas. Prosopis juliflora greatly reduced species richness and basal cover of native herbaceous vegetation in the Allideghi grassland. Analysis of remotely sensed images from the past 30 years indicated major land-use change in the district due to agricultural expansion as well as land-cover change due to Prosopis encroachment and heavy grazing. Recent efforts have been undertaken by various agencies to control P. juliflora, via harvest in the district, but this has yielded variable and often negative results. Without a concerted effort to limit livestock grazing and control spread of P. juliflora, the future for the grassland and wildlife at the Allideghi Wildlife Reserve is grim. Agencies and policy makers need to promote science- and community-based approaches to help rectify the situation. (311 pages)

Anticipated climate change and increasing wood demand require dependable diameter growth models for adaptive forest management. We used a mixed-effects modeling approach with Forest Inventory and Analysis (FIA) data to fit diameter growth models for loblolly pine, other softwood species (slash pine, shortleaf pine, and longleaf pine), sweetgum, and other hardwood (southern red oak, red maple, and water oak) species. Climatic variables coupled with individual tree attributes and competition factors improved climate insensitive models. Growth of loblolly pine and sweetgum was positively correlated with mean temperature of the coldest month. Mean temperature of the warmest month negatively influenced diameter growth of loblolly pine and other hardwood species. Growing season precipitation and summer precipitation balance had negative effects on the growth of softwood and hardwood species, respectively. Inclusion of FIA plot as random effect improved model fit statistics and residual distribution of climate sensitive models. These findings will be useful to managers for recalibrating diameter growth models resulting in improved biomass yield and volume estimates that will better inform decisions.

The Lockheed Fire burned 31 km2 (7,660 acres) of the Scotts Creek watershed in August 2009. 4.5 km2 (1,100 acres) of California Polytechnic State University’s educational and research facility at Swanton Pacific Ranch. The burned region presented an opportunity for studying the hydrologic response of burned soils in the Santa Cruz Mountains where there is insufficient post-fire studies regarding fire-effects on watershed processes such as infiltration and near-surface runoff. Soil infiltration and soil water repellency were evaluated with rainfall simulations, Mini-disk Infiltrometer (MDI) and water drop penetration time tests (WDPT) at sites represented by variations in burn severity, soils, and vegetation types throughout the Scotts Creek watershed each year for 5 years following the burn. Mixed-effects modeling was utilized on the 3 datasets to evaluate if changes could be detected in infiltration rates and water repellency following the fire. Rainfall simulations and WDPT tests showed that the fire did not have a statistically-significant impact on infiltration rates or soil water repellency, whereas the MDI tests detected a statistically-significant impact on post-fire infiltration. While the MDI results showed that fire had a significant impact on the hydrologic response over time, questions arose regarding challenges associated with sampling suggesting the method may not be pursued on steep slopes with high surface rock fragments or in the presence of large soil macropores. It is recognized that additional understanding would be gained from having multiple replications at each site every year and tests could be conducted on a subwatershed scale to account for the naturally occurring variability of larger watersheds.

In 1935 I first visited the Kings Canyon area. Since then I have spent many hours wandering through the woods and over the mountains in the area around the old General Grant National Park and the country which is now included in the Kings Canyon National Park. To my knowledge, no complete flora has been made for this vicinity. I consider the following pages to be the beginning of a fascinating work. It is the beginning because this paper includes only plants with woody stems.

This study focuses on modeling the effects of forest management practices on eco-hydrological processes in the Antalya River Watershed, Turkey. With increasing global pressures from urbanization, deforestation, and climate change affecting water resources and ecosystems, understanding the impact of forest management on vital water sources is essential for sustainable water resource management and ecosystem protection. The Soil and Water Assessment Tool (SWAT) model assessed the hydrological impacts of afforestation and urban forest scenarios in the Antalya River Watershed—the model's parameterization, sensitivity analysis, and calibration phases accurately simulated base watershed processes. The validation process confirmed the accuracy of results, particularly in yearly time steps, providing a comprehensive understanding of the watershed's water management strategies. The results indicate that the afforestation scenario reduced surface runoff and increased lateral flow, decreasing erosion risk and improving groundwater recharge. Although soil evaporation and plant transpiration decreased, the increase in “revap” values highlighted higher water vapor emission from the soil, contributing to atmospheric water cycle processes. Similarly, the urban forest scenario resulted in decreased surface discharge and increased groundwater flow, indicating improved water retention and recharge capabilities. The increased evapotranspiration demonstrated the positive influence of trees and vegetation on the water cycle and atmospheric processes, emphasizing the significance of urban forest applications as valuable nature-based solutions for sustainable water resource management and conservation. In conclusion, implementing afforestation and urban forest initiatives can contribute to ecologically sound utilization of water supplies, enhance ecosystem functioning, and foster resilience in the face of environmental obstacles. The study emphasizes the potential benefits of afforestation and expanding green spaces in promoting sustainable water resources and mitigating erosion and flooding risks. The results of this study provide a scientific basis for policymakers and stakeholders to consider afforestation practices as a vital component of water resource management and watershed conservation strategies.

Temperate forests are complex ecosystems that sequester carbon (C) in biomass. C storage is related to ecosystem-scale forest structure, changing over succession, disturbance, and with community composition. We quantified ecosystem biological and physical structure in two forest chronosequences varying in disturbance intensity, and three late successional functional types to examine how multiple structural expressions relate to ecosystem C cycling. We quantified C cycling as wood net primary production (NPP), ecosystem structure as Simpson’s Index, and physical structure as leaf quantity (LAI) and arrangement (rugosity), examining how wood NPP-structure relates to light distribution and use-efficiency. Relationships between structural attributes of biodiversity, LAI, and rugosity differed. Development of rugosity was conserved regardless of disturbance and composition, suggesting optimization of vegetation arrangement over succession. LAI and rugosity showed significant positive productivity trends over succession, particularly within deciduous broadleaf forests, suggesting these measures of structure contain complementary, not redundant, information related to C cycling.

In ecology literature, there is much data which suggests that conspecific negative density dependence (CNDD) and abiotic disturbances increase biodiversity in forests. This thesis elucidates the notion that not only do these two forces increase diversity, but they may also interact with one another in order to achieve higher levels of biodiversity. Abiotic disturbances, like fires and hurricanes, can indirectly impact conspecific effects because when these forces remove individuals from the landscape, the role of the conspecific effects will change. The interaction of these two factors in biodiversity are explored in an agent based forest simulation through a resource surface. Several different types of abiotic disturbances are simulated with either weak or strong CNDD effects in order to establish that different disturbances and conspecific effects cause certain levels of diversity. The underlying causes for the change in impact is also examined.

The purpose of this study was to determine if control charts are an effective tool to identify trends in forest growth and yield model accuracy. Accurate forest growth and yield models are important for projecting future forest composition. However, environmental factors have the potential to make forest growth models created from historic data inaccurate. Control charts in this study determine if forest growth predictions fall within confidence limits established for historic growth at a number of points in time. Two data sets were used in this study: the first was a Continuous Forest Inventory (CFI) from three tracts at the University of Tennessee Cumberland Research Station and the second data set was Forest Inventory and Analysis data collected by the U.S. Forest Service. The CFI plots represented a stand level data set measured every 5 years from 1962-1977 and revisited for a re-measurement in 2009. The FIA plots were a regional data with subsets of plots measured annually from 1999-2008. The FIA data set was limited to plots of the oak/hickory forest type from Tennessee, Alabama, and Georgia. Two forest growth and yield models were used to predict growth: (1) WinYield and (2) Forest Vegetation Simulator (FVS). The two different data sets were used with both FVS and WinYield to evaluate control charts using different models ad at different spatial and temporal scales. The data sets were also subset by site index, stand age, stocking percent, aspect, and species composition to determine if control charts could identify changes in model accuracy for forests subjected to different growing conditions. The CFI and FIA data had short growth predictions and control charts indicated that there were no trends affecting accuracy. The CFI data also had a long growth prediction of 32 years and the control charts found that the predictions using WinYield and FVS were inaccurate, indicating that there may be a trend causing inaccuracy in the model.