Forest Sciences Commons^™

The Long-Term Effects Of Wildfire Severity On Oak-Pine Communities And Their Microclimates, Scott Glenn Culbert

Theses and Dissertations--Forestry and Natural Resources

In the eastern U.S., fire-dependent tree species have historically dominated upland forest communities, but are now experiencing widespread regeneration challenges as a result of 20^th century fire suppression policies, and are being replaced by mesophytic species. Wildfires that contain areas of high burn severity may provide an important means of mitigating these challenges and facilitating fire-dependent species regeneration and recruitment into larger size classes. One mechanism by which high-severity fire can accomplish this is by modifying understory microclimate characteristics to be more conducive to these species’ growth. A wildfire within the Daniel Boone National Forest, Kentucky, USA, provided the …

Pando's Pulse: Vital Signs Signal Need For Course Correction At World-Renowned Aspen Forest, Paul C. Rogers

Aspen Bibliography

Upland aspen (Populus spp.) forests contribute significantly to biodiversity in their circumboreal role as keystone species. As aspen ecosystems flourish or diminish, myriad dependent species follow suit. The 43-hectare Pando aspen (Populus tremuloides Michx.) clone in Utah, USA, is thought to be the largest living organism on earth, but is faltering due to chronic herbivory. Long-term resilience in aspen communities, including Pando, rests on successful recruitment of vegetative suckers that are nutritiously desirable to browsing ungulates. Here, I evaluate aspen reproduction alongside numerous vital indicators of Pando's status in the first trend assessment of this embattled iconic forest. …

Natural Regeneration Dynamics And Survival Influenced By Abiotic And Biotic Factors In A Bottomland Hardwood Forest, Lydia J. Voth Rurup

Electronic Theses and Dissertations

Riparian ecosystems are vital to the landscape, providing critical services including water filtration and purification, flood and erosion control, carbon sequestration, biodiversity support, and aesthetic value. Bottomland hardwood forests, however, are threatened by invasive species, land loss/conversion, inconsistent or absence of harvesting disturbances, and altered hydrological patterns, leading to reduced success of desired, native species. This research assessed regeneration dynamics and one-year survival in a seasonally-flooded bottomland hardwood forest at Boggy Slough Conservation Area in East Texas to identify abiotic and biotic factors important for successful establishment of native regeneration. Areas sampled included two that were previously treated with herbicide …

The Aboveground And Belowground Growth Characteristics Of Juvenile Conifers In The Southwestern United States, N. L. Pirtel, R. M. Hubbard, J. B. Bradford, T. E. Kolb, M. E. Litvak, Scott Abella, S. L. Porter, Matthew Petrie

Life Sciences Faculty Research

Juvenile tree survival will play an important role in the persistence of coniferous forests and woodlands in the southwestern United States (SWUS). Vulnerability to climatic and environmental stress declines as trees grow, such that larger, more deeply rooted juveniles are less likely to experience mortality. It is unclear how juvenile conifers partition the aboveground and belowground components of early growth, if growth differs between species and ecosystem types, and what environmental factors influence juvenile carbon allocation above- or belowground. We developed a novel data set for four juvenile conifer groups (junipers, piñon pines, ponderosa pines, firs; 1121 juveniles sampled, 221 …

The Effects Of Fire On Oak-Forest Plant Communities Along Soil Moisture Gradients: A 25-Year Study, Rebekah Frances Shupe

Theses, Dissertations and Capstones

In the eastern U.S., fire is a natural disturbance process in Quercus (oak) forests. Fire is thought to promote oak regeneration and plant diversity by reducing competition, preparing a suitable seedbed, and increasing light availability. However, the era of fire suppression that began in the early 20^th century is thought to have negatively impacted oak regeneration and the biodiversity of the understory layer. In this study, we examined the effects of prescribed fire on tree regeneration and the understory layer over 25 years. From a study initiated in 1994, we resampled 45 permanent vegetation plots measuring 1250 m^{2 …}

Floodplain Forest Regeneration Dynamics In The Lower Mississippi River Alluvial Valley, Whitney Anne Kroschel

LSU Doctoral Dissertations

Floodplain forest species diversity is driven, in part, by variation in disturbance regime. Flood patterns create heterogeneity in microsite quality from small differences in elevation across a floodplain which, in turn, influence flood timing and duration. Differences in species’ regeneration niches in relation to hydrologic patterns can account for long-term coexistence of various species. In the past century floodplain forests have exhibited a wide range of changes in stand development and species composition as a result of altered hydrology in rivers and floodplains. I evaluated the role of regeneration in floodplain forest systems of the Lower Mississippi River Alluvial Valley …

Forest Structure Of Long-Term Conserved Areas Utilizing Different Strategies On A Continental, Glacial Moraine Formed Island, Christopher Coggin

Masters Theses, 2010-2019

Understanding patterns of forest succession can help advise management plans within New England nature preserves. This study took place on Block Island, 13 miles off the coast of Rhode Island. The island has greater than 200+ years of farming practices. After 1960, conservation groups began reforesting the island using different strategies, such as actively planting with native and exotic tree species, mowing, and preventing further development. In 2018, woody vegetation was inventoried along transects within four reforested sites. Sites were characterized as the following: actively planted with exotic and native tree species and mowed (AP-M), actively planted with exotic and …

Rapid Regeneration Offsets Losses From Warming-Induced Tree Mortality In An Aspen-Dominated Broad-Leaved Forest In Northern China, Pengwu Zhao, Chongyang Xu, Mei Zhou, Bo Zhang, Peng Ge, Nan Zeng, Hongyan Liu

Aspen Bibliography

Worldwide tree mortality as induced by climate change presents a challenge to forest managers. To successfully manage vulnerable forests requires the capacity of regeneration to compensate for losses from tree mortality. We observed rapid regeneration and the growth release of young trees after warming-induced mortality in a David aspen-dominated (Populus davidiana) broad-leaved forest in Inner Mongolia, China, as based on individual tree measurements taken in 2012 and 2015 from a 6-ha permanent plot. Warming and drought stress killed large trees 10–15 m tall with a total number of 2881 trees during 2011–2012, and also thinned the upper crowns. …

Regeneration Responses To Management For Old-Growth Characteristics In Northern Hardwood-Conifer Forests, Aviva Joy Gottesman

Graduate College Dissertations and Theses

Silviculture practices interact with multiple sources of variability to influence regeneration trends in northern hardwood forests. There is uncertainty whether low-intensity selection harvesting techniques will result in desirable tree regeneration. Our research is part of a long-term study that tests the hypothesis that a silvicultural approach called "structural complexity enhancement" (SCE) can promote accelerated development of late-successional forest structure and functions. Our objective is to understand the regeneration dynamics following three uneven-aged forestry treatments modified to increase postharvest structural retention: single-tree selection, group selection, and SCE. In terms of regeneration densities and composition, how do light availability, competition, seedbad, and …

Forest Islands In A Sea Of Urban Habitat, Michael J. Olejniczak

Biology Theses

Urban forests are poorly defined as ecological communities. Substantive links between anthropogenic landscape features and forest ecology are lacking. ‘Urbaness’ is commonly defined by human population density or land use classifications, but their use is inconsistent throughout the literature, and rarely is linked with ecological processes. Furthermore, it is unknown whether urban forests are functioning parts of a patchy urban woodland system or isolated islands amidst an ocean of unsuitable habitat. I first used digital satellite imagery and publicly available U.S. National Park data to link urban land use with forest processes. I then linked those land use classifications with …

Post-Hurricane Fuel Dynamics And Forest Regeneration Of Coastal Pine Stands In Southeast United States, Shanyue Guan

All Theses

Hurricanes have long been powerful and recurring disturbances in many coastal forest ecosystems. Intense hurricanes often produce a large amount of dead fuels within their affected forests, but how post-hurricane fuel complex changes with time, due to decomposition and management such as salvage, and the fire behavior affected by the changed fuel load remains largely unknown. To better understand the fuel and regeneration dynamics, field measurement and modeling were conducted within undamaged stands and hurricane damaged stands, including salvaged and unsalvaged stands in southern pine forests impacted by hurricane Hugo (1989), Opal (1995), Katrina (2005), and Ike (2008). We found …

Natural Disturbances And The Physiognomy Of Pine Savannas : A Phenomenological Model, Frank S. Gilliam, William J. Platt, Robert K. Peet

Frank S. Gilliam

Abstract. Question: The decline of the Pinus palustris ecosystems has resulted from anthropogenic influences, such as conversion to pine plantation forestry, agriculture and land development, all of which are closely related to increases in human populations. Other effects, however, have arisen from alterations in disturbance regimes that maintain the structure and function of these ecosystems. How have alterations of the disturbance regime altered the physiognomy of ‘old-growth’ stands, and what are the implications for ecosystem conservation and restoration? Methods: In contrast to models that emphasize close interactions among the vertically complex strata, we develop a conceptual phenomenological model for the …

Natural Disturbances And The Physiognomy Of Pine Savannas : A Phenomenological Model, Frank S. Gilliam, William J. Platt, Robert K. Peet

Biological Sciences Faculty Research

Abstract. Question: The decline of the Pinus palustris ecosystems has resulted from anthropogenic influences, such as conversion to pine plantation forestry, agriculture and land development, all of which are closely related to increases in human populations. Other effects, however, have arisen from alterations in disturbance regimes that maintain the structure and function of these ecosystems. How have alterations of the disturbance regime altered the physiognomy of ‘old-growth’ stands, and what are the implications for ecosystem conservation and restoration?

Methods: In contrast to models that emphasize close interactions among the vertically complex strata, we develop a conceptual phenomenological model for the …