Forest Biology Commons^™

Monitoring Fine-Scale Forest Health Using Unmanned Aerial Systems (Uas) Multispectral Models, Benjamin T. Fraser, Russell G. Congalton

Faculty Publications

Forest disturbances—driven by pests, pathogens, and discrete events—have led to billions of dollars in lost ecosystem services and management costs. To understand the patterns and severity of these stressors across complex landscapes, there must be an increase in reliable data at scales compatible with management actions. Unmanned aerial systems (UAS or UAV) offer a capable platform for collecting local scale (e.g., individual tree) forestry data. In this study, we evaluate the capability of UAS multispectral imagery and freely available National Agricultural Imagery Program (NAIP) imagery for differentiating coniferous healthy, coniferous stressed, deciduous healthy, deciduous stressed, and degraded individual trees throughout …

Correcting Tree-Ring Δ13c Time Series For Tree-Size Effects In Eight Temperate Tree Species, Matthew A. Vadeboncoeur, Katie A. Jennings, Andrew P. Ouimette, Heidi Asbjornsen

All Materials

Stable carbon isotope ratios (δ¹³C) in tree rings have been widely used to study changes in intrinsic water-use efficiency (iWUE), sometimes with limited consideration of how C-isotope discrimination is affected by tree height and canopy position. Our goals were to quantify the relationships between tree size or tree microenvironment and wood δ¹³C for eight functionally diverse temperate tree species in northern New England, and to better understand the physical and physiological mechanisms underlying these differences. We collected short increment cores in closed-canopy stands and analyzed δ¹³C in the most recent 5 years of growth. …

Phosphorus Limitation Of Aboveground Production In Northern Hardwood Forests, Shinjini Goswami, Melany C. Fisk, Matthew A. Vadeboncoeur, Mariann Garrison-Johnston, Ruth D. Yanai, Timothy J. Fahey

All Materials

Forest productivity on glacially derived soils with weatherable phosphorus (P) is expected to be limited by nitrogen (N), according to theories of long-term ecosystem development. However, recent studies and model simulations based on resource optimization theory indicate that productivity can be co-limited by N and P. We conducted a full factorial N × P fertilization experiment in 13 northern hardwood forest stands of three age classes in central New Hampshire, USA, to test the hypothesis that forest productivity is co-limited by N and P. We also asked whether the response of productivity to N and P addition differs among species …

Carbon Fluxes And Interannual Drivers In A Temperate Forest Ecosystem Assessed Through Comparison Of Top-Down And Bottom-Up Approaches, Andrew P. Ouimette, Scott V. Ollinger, Andrew D. Richardson, David Y. Hollinger, Trevor F. Keenan, Lucie C. Lepine, Matthew A. Vadeboncoeur

All Materials

Despite decades of research, gaining a comprehensive understanding of carbon (C) cycling in forests remains a considerable challenge. Uncertainties stem from persistent methodological limitations and the difficulty of resolving top-down estimates of ecosystem C exchange with bottom-up measurements of individual pools and fluxes. To address this, we derived estimates and associated uncertainties of ecosystem C fluxes for a 100-125 year old mixed temperate forest stand at the Bartlett Experimental Forest, New Hampshire, USA, using three different approaches: (1) tower-based eddy covariance, (2) a biometric approach involving C flux measurements of individual ecosystem subcomponents, and (3) an inventory approach involving changes …

Hydrological Niche Segregation Defines Forest Structure And Drought Tolerance Strategies In A Seasonal Amazon Forest, Mauro Brum, Matthew A. Vadeboncoeur, Valeriy Ivanov, Heidi Asbjornsen, Scott Saleska, Luciana F. Alves, Deliane Pinha, Jadson D. Dias, Luiz E O C Aragão, Fernanda Barros, Paulo Bittencourt, Luciano Pereira, Rafael S. Oliveira

All Materials

1. The relationship between rooting depth and above‐ground hydraulic traits can potentially define drought resistance strategies that are important in determining species distribution and coexistence in seasonal tropical forests, and understanding this is important for predicting the effects of future climate change in these ecosystems.
2. We assessed the rooting depth of 12 dominant tree species (representing c. 42% of the forest basal area) in a seasonal Amazon forest using the stable isotope ratios (δ¹⁸O and δ²H) of water collected from tree xylem and soils from a range of depths. We took advantage of a major ENSO‐related …

Mycorrhizal Roots In A Temperate Forest Take Up Organic Nitrogen From 13c- And 15n-Labeled Organic Matter, Matthew A. Vadeboncoeur, Andrew P. Ouimette, Erik A. Hobbie

All Materials

Background and Aims

The importance of the uptake of nitrogen in organic form by plants and mycorrhizal fungi has been demonstrated in various ecosystems including temperate forests. However, in previous experiments, isotopically labeled amino acids were often added to soils in concentrations that may be higher than those normally available to roots and mycorrhizal hyphae in situ, and these high concentrations could contribute to exaggerated uptake.

Methods

We used an experimental approach in which we added ¹³C-labeled and ¹⁵N-labeled whole cells to root-ingrowth cores, allowing proteolytic enzymes to release labeled organic nitrogen at a natural rate, as …

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 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.

The Effects Of Forest Fragment Size, Isolation, And Microhabitat Variables On Nest Box Use By Southern Flying Squirrels (Glaucomys Volans) In Southern Illinois, Catherine Wong, Eric K. Bollinger, Thomas A. Nelson

Faculty Publications

We studied the effects of forest fragmentation on southern flying squirrels (Glaucomys volans) in southern Illinois, and examined factors influencing nest box use. Ten nest boxes were placed in each of 30 oak-hickory forest fragments. Nest boxes were checked monthly after installation. We measured habitat variables that described the nest box tree, the microhabitat surrounding the nest box tree, and landscape level characteristics of the fragments (isolation and area). Overall, 78% of the 300 nest boxes were used. Glaucomys volans was captured in 24 of the 30 forest fragments, and evidence of squirrel use was found in 4 additional fragments. …