Trees compete for various resources such as sunlight, water, and nutrients, which can be expressed as numerical terms, called competition indices (CI). Competition between individual trees is correlated with their growth and mortality. Therefore, CIs are used as independent variables to develop, improve and modify growth and yield models. This study was conducted to test the effect of neighborhood competition on tree diameter growth among Douglas-fir (Pseudotsuga menziesii (Mirb.) Franco), western hemlock (Tsuga heterophylla (Raf.) Sarg) and red alder (Alnus rubra Bong.), in the Pacific Northwest Coast Range, USA. After testing seven distance-independent CIs and three distance-dependent CIs, only the distance-independent CIs were found to significantly affect the diameter growth model. Among them, CIs with basal area and diameter information were the most impactful. As a result, a simple CI was very effective in a model that accounts for the basal area information of different tree species.

There are two prevailing views today about our forests and natural resources. Both views are considered the "right" view, each position comprising a set of values by which we make decisions and choices about using our natural resources. The "dominant world view," is anthropocentric and agriculturally based, with a strong belief that we can "fix" environmental problems through the use of technology. The key result of this view is a belief in the efficiency of economic expansion and its continued growth. The second view maintains we are part of nature, not masters of it, and that we have developed an arrogant attitude toward nature, believing we have the right to do as we wish regardless of the consequences. The result of this view is a belief in the interconnectedness of all life, thus all life has rights. This work argues that the "dominant" worldview shaped the policies of the U.S. Forest Service (USFS). Consistent with this worldview, the USFS management. paradigm was to provide the greatest return, a commodity-driven focus. However, when public values changed towards a more ecocentric view, the USFS should have reevaluated its method of doing business. Instead, it remained entrenched in its management objective- timber production. After the courts enjoined the USFS against cutting in the Pacific Northwest, aftet struggling with confrontational environmentalists and increased activism within the agency, the USFS attempted to re-write its management paradigm. However even though the policy sounds eco-friendly, the USFS is still mandated by Congress, and forced by appropriations approved by Congress, to cut trees. Different ideologies are accommodated only when they do not conflict with economics. Thus, in spite of changing values, it is still business as usual.

Historically, the Kentucky Inner Bluegrass blue ash-oak savanna-woodland was the primary ecosystem of the Inner Bluegrass Region (IBR) of Kentucky. After European settlement, the majority (>99%) of Bluegrass savanna was converted to agricultural and urban land uses. Currently remnant savanna tree species are failing to recruit. Therefore, a long-term restoration ecology project researching competition and disturbance on seedling establishment, survival, and growth has been established at Griffith Woods (the largest remaining savanna in Kentucky) in Harrison Co., KY. Fourteen native hardwood tree species (a total of 6,168 seedlings) have been experimentally planted. Light, soil, surrounding vegetation, and herbivory, factors thought to influence seedling survival, have been initially assessed. Results show that soils differed spatially in P, Ca, Mg, Zn, pH, N percent and soil organic matter percent. Light was significantly reduced by diffusive filtering through vegetation. Vegetation biomass was influenced by pH and Mg. Initial seedling survival was high, but significantly differed by species type, location, and soil pH, Mg, and Zn. This research demonstrates that under a similar range of conditions, native hardwood tree seedling establishment is possible. Therefore, the potential exists to restore Bluegrass savanna-woodland in order to return proper ecological functioning into a degraded landscape.

Terrestrial ecosystems in the southeastern United States have evolved with fire as a common disturbance and as a result many natural communities require the presence of fire to persist over time. Human development precludes natural fires from occurring within these communities; however, prescribed fire is considered to be a critical tool in the effort to restore fire-dependent ecosystems after decades of fire exclusion. Direct effects of fire on individual floral and faunal species as well as benefits to biodiversity at the landscape (gamma diversity) level have largely been supported in previous research. However, information on the effects of natural and prescribed fire on plant diversity at the local level (alpha diversity) is limited, particularly for southeastern forests. The applicability of the Intermediate Disturbance Hypothesis (IDH), which suggests that the highest levels of biodiversity are found at intermediate levels of disturbance, is also untested for North Florida upland plant communities. This study compared the effects of fire on local scale mean plant species diversity by examining burned and unburned portions of three fire-dependent communities to determine if there is an effect of prescribed fire on in alpha biodiversity. Alpha biodiversity was not significantly different (p=0.433) between burned and unburned fire-dependent plant communities in northern Florida, suggesting that prescribed fire does not affect plant species diversity in these communities and/or the IDH for plant communities is not supported at the time scale tested. However, the application of prescribed fire did result in changes in abundance of species, particularly with species such as Dicanthelium acuminatum, Quercus myrtifolia, and Vaccinium myrsinites, that respond positively to fire, which may have implications for associated faunal diversity.

Lilium grayi (Gray’s Lily), a southern Appalachian endemic species, is threatened by a Lilium-specific fungal pathogen, Pseudocercosporella inconspicua. The disease is characterized by tan lesions that can cause early senescence, while also lowering seed production and viability. This project tested for P. inconspicua conidia and accessed health at nine locations. The disease was present and ubiquitous across the range of L. grayi. Through identification of P. inconspicua conidia in the field, L. superbum (Turk’s Cap Lily) was identified as an additional host, while L. michauxii (Michaux’s Lily) was disease-free. However, infection was inducible in both species. With the disease widespread in L. superbum and this species represented by many large populations, L. superbum may act as disease reservoir, further complicating the outlook for L. grayi. The disease should be considered an epidemic because of its impact on individual plants, its commonness within populations, and its ubiquity across the geographical range.