Digital Commons Network^™

Drought Sensitivity Of Slash Pine And Longleaf Pine Deduced By Tree Ring Analysis, Conor Madison

Honors Theses and Capstones

Annual tree rings give us the opportunity to investigate the adaptation of trees to climate and environmental changes over a long period of time. In particular, the physical characteristics of each ring (width and earlywood and late wood differentiation) can be used to reconstruct past environment conditions. Physiological responses of trees will be evaluated for two conifers species, i.e. Longleaf pine and Slash pine, giving the opportunity to compare the two species and understand how each species (Longleaf pine and Slash pine) adapt their water use to thrive in such extreme environments. Growth data will then be related to the …

Mechanisms Of Nutrient Limitation And Nutrient Acquisition In Managed And Unmanaged Forest Ecosystems, Matthew A. Vadeboncoeur

Doctoral Dissertations

Understanding the interactions between global change, human and natural disturbances, and other factors on biogeochemical processes in forests is necessary to ensure the sustainability of forest management. Here I report the results of several investigations into nutrient acquisition processes in the forests of New Hampshire. I begin with a meta-analysis of fertilization studies showing that phosphorus (P) and calcium (Ca) as well as nitrogen (N) may limit primary production in deciduous forests of the region. Because these limiting nutrients are all removed from the ecosystem when trees are harvested, I compared nutrient budgets under a range of harvesting scenarios with …

Carbon Benefits From Protected Areas In The Conterminous United States, Daolan Zheng, Linda S. Heath, Mark J. Ducey

Natural Resources & the Environment

Background

Conversion of forests to other land cover or land use releases the carbon stored in the forests and reduces carbon sequestration potential of the land. The rate of forest conversion could be reduced by establishing protected areas for biological diversity and other conservation goals. The purpose of this study is to quantify the efficiency and potential of forest land protection for mitigating GHG emissions.

Results

The analysis of related national-level datasets shows that during the period of 1992–2001 net forest losses in protected areas were small as compared to those in unprotected areas: -0.74% and −4.07%, respectively. If forest …

Plant Community Structure Mediates Potential Methane Production And Potential Iron Reduction In Wetland Mesocosms., Sarah E. Andrews, R Schultz, Serita D. Frey, V Bouchard, R Varner, Mark J. Ducey

Natural Resources & the Environment

Abstract

Wetlands are the largest natural source of methane to the atmosphere, but factors controlling methane emissions from wetlands are a major source of uncertainty in greenhouse gas budgets and projections of future climate change. We conducted a controlled outdoor mesocosm experiment to assess the effects of plant community structure (functional group richness and composition) on potential methane production and potential iron reduction in freshwater emergent marshes. Four plant functional groups (facultative annuals, obligate annuals, reeds, and tussocks) were arranged in a full-factorial design and additional mesocosms were assigned as no-plant controls. Soil samples from the top 10 cm were …

Carbon Benefits From Protected Areas In The Conterminous United States., Daolan Zheng, Linda S. Heath, Mark J. Ducey

Natural Resources & the Environment

Abstract

Background: Conversion of forests to other land cover or land use releases the carbon stored in the forests and reduces carbon sequestration potential of the land. The rate of forest conversion could be reduced by establishing protected areas for biological diversity and other conservation goals. The purpose of this study is to quantify the efficiency and potential of forest land protection for mitigating GHG emissions.Results: The analysis of related national-level datasets shows that during the period of 1992-2001 net forest losses in protected areas were small as compared to those in unprotected areas: -0.74% and -4.07%, respectively. If forest …

Recovery From Disturbance Requires Resynchronization Of Ecosystem Nutrient Cycles, Edward B. Rastetter, Ruth D. Yanai, R Quinn Thomas, Matthew A. Vadeboncoeur, Timothy J. Fahey, Melany C. Fisk, Bonnie L. Kwiatkowski, Steven P. Hamburg

Earth Systems Research Center

Nitrogen (N) and phosphorus (P) are tightly cycled in most terrestrial ecosystems, with plant uptake more than 10 times higher than the rate of supply from deposition and weathering. This near-total dependence on recycled nutrients and the stoichiometric constraints on resource use by plants and microbes mean that the two cycles have to be synchronized such that the ratio of N:P in plant uptake, litterfall, and net mineralization are nearly the same. Disturbance can disrupt this synchronization if there is a disproportionate loss of one nutrient relative to the other. We model the resynchronization of N and P cycles following …

Comparison Of Forest Attributes Derived From Two Terrestrial Lidar Systems., Mark J. Ducey, Rasmus Astrup, Stefan Seifart, Hans Pretzsch, Bruce C. Larson, K David Coates

Natural Resources & the Environment

Terrestrial lidar (TLS) is an emerging technology for deriving forest attributes, including conventional inventory and canopy characterizations. However, little is known about the influence of scanner specifications on derived forest parameters. We compared two TLS systems at two sites in British Columbia. Common scanning benchmarks and identical algorithms were used to obtain estimates of tree diameter, position, and canopy characteristics. Visualization of range images and point clouds showed clear differences, even though both scanners were relatively high-resolution instruments. These translated into quantifiable differences in impulse penetration, characterization of stems and crowns far from the scan location, and gap fraction. Differences …

Climate Change At The Ecosystem Scale: A 50-Year Record In New Hampshire, Steven P. Hamburg, Matthew A. Vadeboncoeur, Andrew D. Richardson, Amey S. Bailey

Earth Systems Research Center

Observing the full range of climate change impacts at the local scale is difficult. Predicted rates of change are often small relative to interannual variability, and few locations have sufficiently comprehensive long-term records of environmental variables to enable researchers to observe the fine-scale patterns that may be important to understanding the influence of climate change on biological systems at the taxon, community, and ecosystem levels. We examined a 50-year meteorological and hydrological record from the Hubbard Brook Experimental Forest (HBEF) in New Hampshire, an intensively monitored Long-Term Ecological Research site. Of the examined climate metrics, trends in temperature were the …

Late-Successional And Old-Growth Forests In The Northeastern United States: Structure, Dynamics, And Prospects For Restoration., Mark J. Ducey, John S. Gunn, Andrew A. Whitman

Natural Resources & the Environment

Abstract

Restoration of old-growth forest structure is an emerging silvicultural goal, especially in those regions where old-growth abundance falls below the historic range of variability. However, longitudinal studies of old-growth dynamics that can inform silvicultural and policy options are few. We analyzed the change in structure, including stand density, diameter distribution, and the abundance of large live, standing dead, and downed dead trees on 58 late-successional and old-growth plots in Maine, USA, and compared these to regional data from the U.S. Forest Inventory and Analysis program. Structural dynamics on the late-successional plots reflected orderly change associated with density-dependent growth and …

Quantifying Carbon Allocation To Mycorrhizal Fungi By Temperate Forest Tree Species Across A Nitrogen Availability Gradient, Shersingh Joseph Tumber-Davila

Honors Theses and Capstones

Terrestrial ecosystems make up the largest carbon pool with a major portion of that being forests. With carbon being a major concern due to global climate change, being able to make accurate models is increasingly important. Studies have shown that trees may allocate up to 50% of their photosynthetically fixed carbon underground; however these values haven’t been accurately quantified and underground carbon allocation has been historically overlooked. Mycorrhizal fungi may be a large portion of underground carbon allocation, as they have a symbiotic relationship with trees where they provide the plant with water and nutrients in return for sugars (carbon). …

The Role Of Landscape Connectivity In Planning And Implementing Conservation And Restoration Priorities. Issues In Ecology, Doborah Rudnick, Sadie J. Ryan, Paul Beier, Samual A. Cushman, Fred Dieffenbach, Clinton Epps, Leah R. Gerber, Joel N. Hartter, Jeff S. Jenness, Julia Kintsch, Adina M. Merenlender, Ryan M. Perkl, Damian V. Perziosi, Stephen C. Trombulack

Geography

Landscape connectivity, the extent to which a landscape facilitates the movements of organisms and their genes, faces critical threats from both fragmentation and habitat loss. Many conservation efforts focus on protecting and enhancing connectivity to offset the impacts of habitat loss and fragmentation on biodiversity conservation, and to increase the resilience of reserve networks to potential threats associated with climate change. Loss of connectivity can reduce the size and quality of available habitat, impede and disrupt movement (including dispersal) to new habitats, and affect seasonal migration patterns. These changes can lead, in turn, to detrimental effects for populations and species, …

The Quantitative Soil Pit Method For Measuring Belowground Carbon And Nitrogen Stocks, Matthew A. Vadeboncoeur, Steven P. Hamburg, Joel D. Blum, Michael J. Pennino, Ruth D. Yanai, Chris E. Johnson

Earth Systems Research Center

Many important questions in ecosystem science require estimates of stocks of soil C and nutrients. Quantitative soil pits provide direct measurements of total soil mass and elemental content in depth-based samples representative of large volumes, bypassing potential errors associated with independently measuring soil bulk density, rock volume, and elemental concentrations. The method also allows relatively unbiased sampling of other belowground C and nutrient stocks, including roots, coarse organic fragments, and rocks. We present a comprehensive methodology for sampling these pools with quantitative pits and assess their accuracy, precision, effort, and sampling intensity as compared to other methods. At 14 forested …

A Comparison Of Presettlement And Modern Forest Composition Along An Elevation Gradient In Central New Hampshire, Matthew A. Vadeboncoeur, Steven P. Hamburg, Charles V. Cogbill, Wendy Y. Sugimura

Earth Systems Research Center

Tree species composition is influenced not only by edaphic and climatic factors but also by natural and human-caused disturbances. To understand interactions among these influences, we compared forest species composition data from the time of European settlement with modern data. We derived elevation data for 2529 trees mapped by early land surveys (1770–1850) across a 1000 m elevation gradient in central New Hampshire and compared these with modern data (2004–2009) from the Forest Inventory and Analysis program (123 plots containing 2126 trees) and from permanent plots representing case studies of different land-use histories. Spruce and beech are much less abundant …

Carbon Changes In Conterminous Us Forests Associated With Growth And Major Disturbances., Daolan Zheng, Linda S. Heath, Mark J. Ducey, James E. Smith

Natural Resources & the Environment

Abstract

We estimated forest area and carbon changes in the conterminous United States using a remote sensing based land cover change map, forest fire data from the Monitoring Trends in Burn Severity program, and forest growth and harvest data from the USDA Forest Service, Forest Inventory and Analysis Program. Natural and human-associated disturbances reduced the forest ecosystems' carbon sink by 36% from 1992 to 2001, compared to that without disturbances in the 48 states. Among the three identified disturbances, forest-related land cover change contributed 33% of the total effect in reducing the forest carbon potential sink, while harvests and fires …

Use Of Waveform Lidar And Hyperspectral Sensors To Assess Selected Spatial And Structural Patterns Associated With Recent And Repeat Disturbance And The Abundance Of Sugar Maple (Acer Saccharum Marsh.) In A Temperate Mixed Hardwood And Conifer Forest., Jeanne E. Anderson, Mark J. Ducey, Andrew J. Fast, Mary E. Martin, Lucie C. Lepine, Marie-Louise Smith, Thomas D. Lee, Ralph O. Dubayah, Michelle A. Hofton, Peter Hyde, Birgit E. Peterson, J. Bryan Blair

Natural Resources & the Environment

Abstract

Waveform lidar imagery was acquired on September 26, 1999 over the Bartlett Experimental Forest (BEF) in New Hampshire (USA) using NASA's Laser Vegetation Imaging Sensor (LVIS). This flight occurred 20 months after an ice storm damaged millions of hectares of forestland in northeastern North America. Lidar measurements of the amplitude and intensity of ground energy returns appeared to readily detect areas of moderate to severe ice storm damage associated with the worst damage. Southern through eastern aspects on side slopes were particularly susceptible to higher levels of damage, in large part overlapping tracts of forest that had suffered the …

Modeled Nitrogen Loading To Narragansett Bay: 1850 To 2015, Matthew A. Vadeboncoeur, Steven P. Hamburg, Donald Pryor

Earth Systems Research Center

Nutrient loading to estuaries with heavily populated watersheds can have profound ecological consequences. In evaluating policy options for managing nitrogen (N), it is helpful to understand current and historic spatial loading patterns to the system. We modeled N inputs to Narragansett Bay from 1850 to 2000, using data on population, human waste disposal, livestock, fertilizer, and atmospheric deposition. We found that total N loading to the bay increased 250% from 1850 to 2000, and 80% from 1900 to 2000. Loading to the upper bay increased far more than that to the lower bay, and the most important source shifted from …

Meta-Analysis Of Fertilization Experiments Indicates Multiple Limiting Nutrients In Northeastern Deciduous Forests, Matthew A. Vadeboncoeur

Earth Systems Research Center

It is widely accepted that nitrogen limits primary production in temperate forests, although co-limitation by N and P has also been suggested, and on some soils Ca and base cations are in short supply. I conducted a meta-analysis to assess the strength of existing experimental evidence for limitation of primary production by N, P, and Ca in hardwood forests of the northeastern United States and southeastern Canada, using data from 35 fertilization experiments in deciduous forests on glaciated soils across the region.

There is strong evidence for N limitation (formal meta-analysis weighted mean response ratio = 1.51, p < 0.01; simple mean = 1.42, p < 0.001). Forest productivity also tends to increase with additions of P (simple mean = 1.15, p = 0.05) and Ca (simple mean = 1.36 p < 0.001). Across all treatments, 85% of response ratios were positive. Multiple-element additions had larger effects than single elements, but factorial experiments showed little evidence of synergistic effects between nutrient additions. Production responses correlated positively with the rate of N fertilization, but this effect was reduced at high rates of ambient N deposition.

Parks, People And Pixels: Evaluating Landscape Effects Of An East African National Park On Its Surroundings, Jane Southworth, Joel N. Hartter, Michael W. Binford, Abraham Goldman, Colin A. Chapman, Lauren J. Chapman, Patrick Omeja, Elizabeth Binford

Geography

Landscapes surrounding protected areas, while still containing considerable biodiversity, have rapidly growing human populations and associated agricultural development in most of the developing world that tend to isolate them, potentially reducing their conservation value. Using field studies and multi-temporal Landsat imagery, we examine a forest park, Kibale National Park in western Uganda, its changes over time, and related land cover change in the surrounding landscape. We find Kibale has successfully defended its borders and prevents within-park deforestation and other land incursions, and has maintained tree cover throughout the time period of the study. Outside the park there was a significant …

The Loss Of Species: Mangrove Extinction Risk And Geographic Areas Of Global Concern, Beth A. Liu, Kent A. Carpenter, Lorna Collins, Norma C. Duke, Aaron M. Ellison, Joanne C. Ellison, Elizabeth J. Farnsworth, Edwino S. Fernando, Kandasamy Kathiresan, Nico E. Koedam, Suzanne R. Livingstone, Toyohiko Miyagi, Gregg E. Moore, Vien Ngoc Nam, Jin Eong Ong, Jurgenne H. Primavera, Severino G. Salmo Iii, Jonnell C. Sanciangco, Sukristijono Sukardjo, Yamin Wang, Jean Wan Hong Yong

Biological Sciences

Mangrove species are uniquely adapted to tropical and subtropical coasts, and although relatively low in number of species, mangrove forests provide at least US $1.6 billion each year in ecosystem services and support coastal livelihoods worldwide. Globally, mangrove areas are declining rapidly as they are cleared for coastal development and aquaculture and logged for timber and fuel production. Little is known about the effects of mangrove area loss on individual mangrove species and local or regional populations. To address this gap, species-specific information on global distribution, population status, life history traits, and major threats were compiled for each of the …

Potential Applications Of Randomised Graph Sampling To Invasive Species Surveillance And Monitoring., Mark J. Ducey, Kathleen M. O'Brien

Natural Resources & the Environment

Abstract

Many invasive plants and animals disperse preferentially through linear networks in the landscape, including road networks, riparian corridors, and power transmission lines. Unless the network of interest is small, or the budget for surveillance is large, it may be necessary to draw inferences from a sample rather than a complete census on the network. Desired features of a surveillance system to detect and quantify invasion include: (1) the ability to make unbiased statements about the spatial extent of invasion, the abundance of the invading organism, and the degree of impact; (2) the ability to quantify the uncertainty associated with …

Methods For Disposing Non-Native Invasive Plants, Karen Bennett

UNH Cooperative Extension

No abstract provided.

Ice Storm Effects On The Canopy Structure Of A Northern Hardwood Forest After 8 Years, Brian C. Weeks, Steven P. Hamburg, Matthew A. Vadeboncoeur

Earth Systems Research Center

Ice storms can cause severe damage to forest canopies, resulting in differential mortality among tree species and size classes and leading to long-lasting changes in the vertical structure and composition of the forest. An intense ice storm in 1998 damaged large areas of the northern hardwood forest, including much of the Hubbard Brook Experimental Forest, New Hampshire (USA). Following up on detailed poststorm assessments, we measured changes in the vertical structure of the forest canopy 8 years poststorm. We focused on how the presence of disease-induced advance regeneration of American beech (Fagus grandifolia Ehrh.) has affected canopy structure in the …

Integrating Landscapes That Have Experienced Rural Depopulation And Ecological Homogenization Into Tropical Conservation Planning, Aerin L. Jacob, Ismael Vaccaro, Raja Sengupta, Joel N. Hartter, Colin A. Chapman

Geography

If current trends of declining fertility rates and increasing abandonment of rural land as a result of urbanization continue, this will signal a globally significant transformation with important consequences for policy makers interested in conservation planning. This transformation is presently evident in a number of countries and projections suggest it may occur in the future in many developing countries. We use rates of population growth and urbanization to project population trends in rural areas for 25 example countries. Our projections indicate a general decline in population density that has either occurred already (e.g., Mexico) or may occur in the future …

Spatial Distribution Of Forest Aboveground Biomass Estimated From Remote Sensing And Forest Inventory Data In New England, Usa., Daolan Zheng, Linda S. Heath, Mark J. Ducey

Natural Resources & the Environment

Abstract

We combined satellite (Landsat 7 and Moderate Resolution Imaging Spectrometer) and U.S. Department of Agriculture forest inventory and analysis (FIA) data to estimate forest aboveground biomass (AGB) across New England, USA. This is practical for large-scale carbon studies and may reduce uncertainty of AGB estimates. We estimate that total regional forest AGB was 1,867 teragram (1012, dry weight) in 2001, with a mean AGB density of 120 Mg/ha (Standard deviation = 54 Mg/ha) ranging from 15 to 240 Mg/ha within a 95% percentile. The majority of regional AGB density was in the range of 80 to 160 Mg/ha (58.2%). …

Terrestrial Gastropod Responses To An Ecosystem-Level Calcium Manipulation In A Northern Hardwood Forest, Monica A. Skeldon, Matthew A. Vadeboncoeur, Steven P. Hamburg, Joel D. Blum

Earth Systems Research Center

The effects of acid deposition on soil calcium (Ca), and in turn on land snail populations, have been of heightened concern for several decades. We compiled a 10 year record (1997–2006) of gastropod abundance on two small watersheds at the Hubbard Brook Experimental Forest, one of which was treated with a Ca addition in 1999. In years 3–7 post Ca addition, snail abundance in the treated watershed was 73% higher than in the reference area (p < 0.001); there was no significant difference in the 3 years prior to treatment, and no significant difference in slug abundance in any year. We analyzed relationships between snail density and microsite spatial variation in leaf-litter Ca concentration, litter-layer thickness, tree species composition, slope, dead wood, and forest-floor light level. We found that snail abundance was significantly correlated with litter Ca concentration (p < 0.001) and negatively correlated with the importance value of American beech (p = 0.05). Isotopic-tracer analysis indicated that, on average, 76% of Ca in snail shells 5 years post treatment was derived from the added Ca. However, interannual variation in snail numbers indicates that other factors beyond available Ca have a strong influence on snail abundance.

Validation And Refinement Of Allometric Equations For Roots Of Northern Hardwoods, Matthew A. Vadeboncoeur, Steven P. Hamburg, Ruth D. Yanai

Earth Systems Research Center

The allometric equations developed by Whittaker et al. (1974. Ecol. Monogr. 44: 233–252), at the Hubbard Brook Experimental Forest have been used to estimate biomass and productivity in northern hardwood forest systems for over three decades. Few other species-specific allometric estimates of belowground biomass are available because of the difficulty in collecting the data, and such equations are rarely validated. Using previously unpublished data from Whittaker’s sampling effort, we extended the equations to predict the root crown and lateral root components for the three dominant species of the northern hardwood forest: American beech (Fagus grandifolia Ehrh.), yellow birch (Betula alleghaniensis …

Research On Synthetic Rope And Its Future In Timber Harvesting, Joel N. Hartter, Jared Leonard, John Garland, Steve Pilkerton

Geography

Steel wire rope is used for many logging applications. It has served the industry well in terms of strength, durability, and longevity. However, steel wire rope is difficult to use because it is stiff, heavy, and unyielding. These characteristics can lead to fatigue and exhaustion, and may contribute to worker injuries. Ultra-high molecular weight polyethylene synthetic rope has the potential to replace steel wire rope for selected logging applications. Research shows ergonomic gains and other operational effectiveness with its use. This paper presents research results, potentials, and issues in improving economic and ergonomic performance of ground-based and cable logging. Potential …

The Forester's Dilemma : Paradoxes In The Criteria And Indicators For Sustainable Forestry, Theodore E. Howard

New Hampshire Agricultural Experiment Station Publications

Since sustainable forestry is a complex endeavor, paradoxes naturally exist in the certification criteria and indicators. There are different ways to establish the sustainability horizon and alternative harvest profiles that, although sustainable, may not meet specific criteria. The application of historic range of variation data and criteria must confront issues of time and spatial scales as well as how much human disturbance is natural. Defining “local” in the bioregional context is important for addressing socioeconomic criteria. The forester’s ability to deal with the self-contradictions in the criteria and indicators of sustainable forestry will improve with experience in the certification process.