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Articles 1 - 30 of 247
Full-Text Articles in Life Sciences
Disturbance Reduces Fungal White-Rot Litter Mat Cover In A Wet Subtropical Forest, D. Jean Lodge, Ashley E. Van Beusekom, Grizelle González, Mareli Sánchez-Julia, Sarah Stankavich
Disturbance Reduces Fungal White-Rot Litter Mat Cover In A Wet Subtropical Forest, D. Jean Lodge, Ashley E. Van Beusekom, Grizelle González, Mareli Sánchez-Julia, Sarah Stankavich
USDA Forest Service / UNL Faculty Publications
Fungi that bind leaf litter into mats and produce white-rot via degradation of lignin and other aromatic compounds influence forest nutrient cycling and soil fertility. Extent of white-rot litter mats formed by basidiomycete fungi in Puerto Rico decreased in response to disturbances—a simulated hurricane treatment executed by canopy trimming and debris addition in 2014, a drought in 2015, a treefall, and two hurricanes 10 days apart in September 2017. Percent fungal litter mat cover ranged from 0.4% after Hurricanes Irma and Maria to a high of 53% in forest with undisturbed canopy prior to the 2017 hurricanes, with means mostly …
Synthesizing Conservation Motivations And Barriers: What Have We Learned From Qualitative Studies Of Farmers’ Behaviors In The United States?, Pranay Ranjan, Sarah P. Church, Kristin Floress, Linda S. Prokopy
Synthesizing Conservation Motivations And Barriers: What Have We Learned From Qualitative Studies Of Farmers’ Behaviors In The United States?, Pranay Ranjan, Sarah P. Church, Kristin Floress, Linda S. Prokopy
USDA Forest Service / UNL Faculty Publications
Since 2011, qualitative studies examining adoption of conservation practices and programs (CPPs) have burgeoned. This article presents a systematic review of all U.S.-based qualitative investigations into CPP adoption since 1996. We found three themes are discussed primarily as motivating adoption: farmer characteristics, environmental awareness, and trust in information sources. Four themes are discussed primarily as barriers to adoption: farm management, negative perceptions of a conservation practice, perceptions that adoption is a risk, and land tenure. Four themes were discussed as both motivations and barriers: economic factors, social norms, perceptions of government programs, and farm characteristics. Overall, we found farmers’ economic …
Habitat Characteristics And Selection By Ornate Box Turtles In The Sandhills Of South Dakota, Daniel W, Uresk, Alessandra Higa
Habitat Characteristics And Selection By Ornate Box Turtles In The Sandhills Of South Dakota, Daniel W, Uresk, Alessandra Higa
USDA Forest Service / UNL Faculty Publications
The ornate box turtle (Terrapene ornata Agassiz) is a species of greatest conservation need in South Dakota. Habitat loss through agricultural development and fragmentation is the main threat to the species throughout its range, which extends from Wisconsin and northern Indiana through the central Great Plains, and from southern South Dakota to Arizona, northern Mexico, and the Gulf Coast of Texas. The objectives of this study were to determine the ornate box turtle’s preferred vegetation characteristics (microhabitat) compared to the available habitat (macrohabitat) on the Pine Ridge Reservation, South Dakota Sandhills region, during 2010–2011. In both years, using a modified …
Hillslope Hydrology In Global Change Research And Earth System Modeling, Y. Fan, M. Clark, D. M. Lawrence, S. Swenson, L.E. Band, S. L. Brantley, P. D. Brooks, W. E. Dietrich, A. Flores, G. Grant, J.W. Kirchner, D. S. Mackay, J. J. Mcdonnell, P. C. D. Milly, P. L. Sullivan, C. Tague, H. Ajami, N. Chaney, A. Hartmann, P. Hazenberg, J. Mcnamara, J. Pelletier, J. Perket, E. Rouholahnejad‐Freund, T. Wagener, X. Zeng, E. Beighley, J. Buzan, M. Huang, B. Livneh, B. P. Mohanty, B. Nijssen, M. Safeeq, C. Shen, W. Van Verseveld, J. Volk, D. Yamazaki
Hillslope Hydrology In Global Change Research And Earth System Modeling, Y. Fan, M. Clark, D. M. Lawrence, S. Swenson, L.E. Band, S. L. Brantley, P. D. Brooks, W. E. Dietrich, A. Flores, G. Grant, J.W. Kirchner, D. S. Mackay, J. J. Mcdonnell, P. C. D. Milly, P. L. Sullivan, C. Tague, H. Ajami, N. Chaney, A. Hartmann, P. Hazenberg, J. Mcnamara, J. Pelletier, J. Perket, E. Rouholahnejad‐Freund, T. Wagener, X. Zeng, E. Beighley, J. Buzan, M. Huang, B. Livneh, B. P. Mohanty, B. Nijssen, M. Safeeq, C. Shen, W. Van Verseveld, J. Volk, D. Yamazaki
USDA Forest Service / UNL Faculty Publications
Earth System Models (ESMs) are essential tools for understanding and predicting global change, but they cannot explicitly resolve hillslope‐scale terrain structures that fundamentally organize water, energy, and biogeochemical stores and fluxes at subgrid scales. Here we bring together hydrologists, Critical Zone scientists, and ESM developers, to explore how hillslope structures may modulate ESM grid‐level water, energy, and biogeochemical fluxes. In contrast to the one‐dimensional (1‐D), 2‐ to 3‐mdeep, and free‐draining soil hydrology in most ESM land models, we hypothesize that 3‐D, lateral ridge‐to‐valley flow through shallow and deep paths and insolation contrasts between sunny and shady slopes are the top …
Biological Aspects Of Mountain Pine Beetle In Lodgepole Pine Stands Of Different Densities In Colorado, Usa, Jose Negron
Biological Aspects Of Mountain Pine Beetle In Lodgepole Pine Stands Of Different Densities In Colorado, Usa, Jose Negron
USDA Forest Service / UNL Faculty Publications
Research Highlights: The biology of mountain pine beetle (MPB), Dendroctonus ponderosae Hopkins, in Colorado’s lodgepole pine forests exhibits similarities and differences to other parts of its range. Brood emergence was not influenced by stand density nor related to tree diameter. The probability of individual tree attack is influenced by stocking and tree size. Findings have implications for understanding MPB as a disturbance agent and for developing management strategies. Background and Objectives: MPB causes extensive tree mortality of lodgepole pine, Pinus contorta Douglas ex Loudon, across the western US and Canada and is probably the most studied bark beetle in North …
Improving Ecological Restoration To Curb Biotic Invasion—A Practical Guide, Qinfeng Guo, Dale G. Brockway, Diane L. Larson, Deli Wang, Hai Ren
Improving Ecological Restoration To Curb Biotic Invasion—A Practical Guide, Qinfeng Guo, Dale G. Brockway, Diane L. Larson, Deli Wang, Hai Ren
USDA Forest Service / UNL Faculty Publications
Common practices for invasive species control and management include physical, chemical, and biological approaches. The first two approaches have clear limitations and may lead to unintended (negative) consequences, unless carefully planned and implemented. For example, physical removal rarely completely eradicates the targeted invasive species and can cause disturbances that facilitate new invasions by nonnative species from nearby habitats. Chemical treatments can harm native, and especially rare, species through unanticipated side effects. Biological methods may be classified as biocontrol and the ecological approach. Similar to physical and chemical methods, biocontrol also has limitations and sometimes leads to unintended consequences. Therefore, a …
Short Communications: First Tracking Of Individual American Robins (Turdus Migratorius) Across Seasons, Alex E. Jahn, Susannah B. Lerman, Laura M. Phillips, Thomas B. Ryder, Emily J. Williams
Short Communications: First Tracking Of Individual American Robins (Turdus Migratorius) Across Seasons, Alex E. Jahn, Susannah B. Lerman, Laura M. Phillips, Thomas B. Ryder, Emily J. Williams
USDA Forest Service / UNL Faculty Publications
The American Robin (Turdus migratorius) is one of the most widespread, common bird species in North America; yet, very little is known about its migratory connectivity, migration timing, and migratory routes. Using archival GPS tags, we tracked the movements of 7 individual robins from 3 breeding populations in the United States. Four robins captured in Denali National Park and Preserve, Alaska, overwintered in Texas, Nebraska, Oklahoma, and Montana, up to 4,500 km from the capture location. One robin captured in Amherst, Massachusetts, overwintered in South Carolina 1,210 km from the capture location, whereas 2 robins captured in Washington, D.C., spent …
Tamm Review: Reforestation For Resilience In Dry Western U.S. Forests, Malcolm P. North, Jens T. Stevens, David F. Greene, Michelle Coppoletta, Eric E. Knapp, Andrew M. Latimer, Christina M. Restaino, Ryan E. Tompkins, Kevin R. Welch, Rob A. York, Derek J.N. Young, Jodi N. Axelson, Tom N. Buckley, Becky L. Estes, Rachel N. Hager, Jonathan W. Long, Marc D. Meyer, Steven M. Ostoja, Hugh D. Safford, Kristen L. Shive, Carmen L. Tubbesing, Dana Walsh, Chhaya M. Werner, Peter Wyrsch, Heather Vice
Tamm Review: Reforestation For Resilience In Dry Western U.S. Forests, Malcolm P. North, Jens T. Stevens, David F. Greene, Michelle Coppoletta, Eric E. Knapp, Andrew M. Latimer, Christina M. Restaino, Ryan E. Tompkins, Kevin R. Welch, Rob A. York, Derek J.N. Young, Jodi N. Axelson, Tom N. Buckley, Becky L. Estes, Rachel N. Hager, Jonathan W. Long, Marc D. Meyer, Steven M. Ostoja, Hugh D. Safford, Kristen L. Shive, Carmen L. Tubbesing, Dana Walsh, Chhaya M. Werner, Peter Wyrsch, Heather Vice
USDA Forest Service / UNL Faculty Publications
The increasing frequency and severity of fire and drought events have negatively impacted the capacity and success of reforestation efforts in many dry, western U.S. forests. Challenges to reforestation include the cost and safety concerns of replanting large areas of standing dead trees, and high seedling and sapling mortality rates due to water stress, competing vegetation, and repeat fires that burn young plantations. Standard reforestation practices have emphasized establishing dense conifer cover with gridded planting, sometimes called 'pines in lines', followed by shrub control and pre-commercial thinning. Resources for such intensive management are increasingly limited, reducing the capacity for young …
On-Road Emissions Of Ammonia: An Underappreciated Source Of Atmospheric Nitrogen Deposition, Mark E. Fenn, Andrzej Bytnerowicz, Susan L. Schilling, Dena M. Vallano, Erika S. Zavaleta, Stuart B. Weiss, Connor Morozumi, Linda H. Geiser, Kenneth Hanks
On-Road Emissions Of Ammonia: An Underappreciated Source Of Atmospheric Nitrogen Deposition, Mark E. Fenn, Andrzej Bytnerowicz, Susan L. Schilling, Dena M. Vallano, Erika S. Zavaleta, Stuart B. Weiss, Connor Morozumi, Linda H. Geiser, Kenneth Hanks
USDA Forest Service / UNL Faculty Publications
We provide updated spatial distribution and inventory data for on-road NH3 emissions for the continental United States (U.S.) On-road NH3 emissions were determined from on-road CO2 emissions data and empirical NH3:CO2 vehicle emissions ratios. Emissions of NH3 from on-road sources in urbanized regions are typically 0.1– 1.3 t km−2 yr−1 while NH3 emissions in agricultural regions generally range from 0.4–5.5 t km−2 yr−1, with a few hot spots as high as 5.5–11.2 t km−2 yr−1. Counties with higher vehicle NH3 emissions than from agriculture …
Ecological-Economic Assessment Of The Effects Of Freshwater Flow In The Florida Everglades On Recreational Fisheries, Christina Estela Brown, Mahadev G. Bhat, Jennifer S. Rehage, Ali Mirchi, Ross Boucek, Victor Engel, Jerald S. Ault, Pallab Mozumder, David Watkins, Michael Sukop
Ecological-Economic Assessment Of The Effects Of Freshwater Flow In The Florida Everglades On Recreational Fisheries, Christina Estela Brown, Mahadev G. Bhat, Jennifer S. Rehage, Ali Mirchi, Ross Boucek, Victor Engel, Jerald S. Ault, Pallab Mozumder, David Watkins, Michael Sukop
USDA Forest Service / UNL Faculty Publications
This research develops an integrated methodology to determine the economic value to anglers of recreational fishery ecosystem services in Everglades National Park that could result from different water management scenarios. The study first used bio-hydrological models to link managed freshwater inflows to indicators of fishery productivity and ecosystem health, then link those models to anglers' willingness-to-pay for various attributes of the recreational fishing experience and monthly fishing effort. This approach allowed us to estimate the foregone economic benefits of failing to meet monthly freshwater delivery targets. The study found that the managed freshwater delivery to the Park had declined substantially …
Native And Agricultural Forests At Risk To A Changing Climate In The Northern Plains, Linda A. Joyce, Gary Bentrup, Antony S. Cheng, Peter Kolb, Michele Schoeneberger, Justin Derner
Native And Agricultural Forests At Risk To A Changing Climate In The Northern Plains, Linda A. Joyce, Gary Bentrup, Antony S. Cheng, Peter Kolb, Michele Schoeneberger, Justin Derner
USDA Forest Service / UNL Faculty Publications
Native and agricultural forests in the Northern Plains provide ecosystem services that benefit human society—diversified agricultural systems, forest-based products, and rural vitality. The impacts of recent trends in temperature and disturbances are impairing the delivery of these services. Climate change projections identify future stressors of greater impact, placing at risk crops, soils, livestock, biodiversity, and agricultural and forest-based livelihoods. While these native and agricultural forests are also a viable option for providing mitigation and adaptation services to the Northern Plains, they themselves must be managed in terms of climate change risks. Because agricultural forests are planted systems, the primary approaches …
Shape Indexes For Semi-Automated Detection Of Windbreaks In Thematic Tree Cover Maps From The Central United States, Greg C. Liknes, Dacia M. Meneguzzo, Todd A. Kellerman
Shape Indexes For Semi-Automated Detection Of Windbreaks In Thematic Tree Cover Maps From The Central United States, Greg C. Liknes, Dacia M. Meneguzzo, Todd A. Kellerman
USDA Forest Service / UNL Faculty Publications
Windbreaks are an important ecological resource across the large expanse of agricultural land in the central United States and are often planted in straight-line or L-shaped configurations to serve specific functions. As high-resolution (i.e., <5 m) land cover data sets become more available for these areas, semi-or fully-automated methods for distinguishing windbreaks from other patches of trees are needed for use with thematic raster data sets. To address this need, we created three shape indexes: a morphology-based index that we have named the Straight and Narrow Feature Index (SNFI), a windbreak sinuosity index, and an area index indicating the occupied fractional area of a bounding box. The indexes were tested in two study areas: (1) a riparian area dominated by sinuous bands of trees but mixed with row crop agriculture and (2) an agricultural area with a mix of straight-line and L-shaped windbreaks. In the riparian area, a Kruskall–Wallis rank sum test indicated class differences for all three indexes, and pairwise comparisons indicate windbreaks and riparian trees are separable using any of the three indexes. SNFI also produced significant differences between windbreaks oriented in different directions (east–west vs. north–south). In the agricultural area, the Kruskall–Wallis rank sum test indicated differences between classes for all three indexes, and pairwise comparisons show that all class pairs have significant differences for at least one index, with the exception of L-shaped windbreaks vs. non-windbreak tree patches. We also used classification trees to objectively assign representative samples of tree patches to classes using both single indexes and multiple indexes. Classes were correctly assigned for more than 90% of the samples in both the riparian and agricultural study areas. In the riparian area, combining indexes did not improve accuracy compared to using SNFI alone, whereas in the agricultural area, combining the three indexes produced the best result. Thematic data sets derived from high-resolution imagery are becoming more available, and extracting useful information can be a challenge, partly due to the large amount of data to assess. Calculating the three shape indexes presented can assist with efficient identification of candidate windbreaks and as such, hold good promise for value-added analysis of tree function in the central United States.
Are Northeastern U.S. Forests Vulnerable To Extreme Drought?, Adam P. Coble, Matthew A. Vadeboncoeur, Z. Carter Berry, Katie A. Jennings, Cameron D. Mcintire, John L. Campbell, Lindsey E. Rustad, Pamela H. Temper, Heidi Asbjornsen
Are Northeastern U.S. Forests Vulnerable To Extreme Drought?, Adam P. Coble, Matthew A. Vadeboncoeur, Z. Carter Berry, Katie A. Jennings, Cameron D. Mcintire, John L. Campbell, Lindsey E. Rustad, Pamela H. Temper, Heidi Asbjornsen
USDA Forest Service / UNL Faculty Publications
In the Northeastern U.S., drought is expected to increase in frequency over the next century, and therefore, the responses of trees to drought are important to understand. There is recent debate about whether land-use change or moisture availability is the primary driver of changes in forest species composition in this region. Some argue that fire suppression from the early twentieth century to present has resulted in an increase in shade-tolerant and pyrophobic tree species that are drought intolerant, while others suggest precipitation variability as a major driver of species composition. From this debate, an emerging hypothesis is that mesophication and …
An Artificial Neural Network For Real-Time Hardwood Lumber Grading, Edward Thomas
An Artificial Neural Network For Real-Time Hardwood Lumber Grading, Edward Thomas
USDA Forest Service / UNL Faculty Publications
Computerized grading of hardwood lumber according to NHLA rules would permit fast assessment of sawn lumber and the evaluation of potential edging and trimming operations to improve lumber value. More importantly, to enable optimization of the hardwood lumber sawing process, a fast means of evaluating the potential value of boards before they are sawn is necessary. As log and lumber scanning systems become prevalent and common, these needs become more pressing. From an automation perspective, the NHLA lumber grades are difficult to implement efficiently in a computer program. Exhaustive approaches that examine every potential cutting size and combination to determine …
Interactions Between White-Tailed Deer Density And The Composition Of Forest Understories In The Northern United States, Matthew B. Russell, Christopher W. Woodall, Kevin M. Potter, Brian F. Walters, Grant M. Domke, Christopher M. Oswalt
Interactions Between White-Tailed Deer Density And The Composition Of Forest Understories In The Northern United States, Matthew B. Russell, Christopher W. Woodall, Kevin M. Potter, Brian F. Walters, Grant M. Domke, Christopher M. Oswalt
USDA Forest Service / UNL Faculty Publications
Forest understories across the northern United States (US) are a complex of tree seedlings, endemic forbs, herbs, shrubs, and introduced plant species within a forest structure defined by tree and forest floor attributes. The substantial increase in white-tailed deer (Odocoileus virginianus Zimmerman) populations over the past decades has resulted in heavy browse pressure in many of these forests. To gain an objective assessment of the role of deer in forested ecosystems, a region-wide forest inventory across the northern US was examined in concert with white-tailed deer density information compiled at broad scales. Results indicate that deer density may be …
Residential Building Energy Conservation And Avoided Power Plant Emissions By Urban And Community Trees In The United States, David J. Nowak, Nathaniel Appleton, Alexis Ellis, Eric Greenfield
Residential Building Energy Conservation And Avoided Power Plant Emissions By Urban And Community Trees In The United States, David J. Nowak, Nathaniel Appleton, Alexis Ellis, Eric Greenfield
USDA Forest Service / UNL Faculty Publications
Urban trees and forests alter building energy use and associated emissions from power plants by shading buildings, cooling air temperatures and altering wind speeds around buildings. Field data on urban trees were combined with local urban/community tree and land cover maps, modeling of tree effects on building energy use and pollutant emissions, and state energy and pollutant costs to estimate tree effects on building energy use and associated pollutant emissions at the state to national level in the conterminous United States. Results reveal that trees and forests in urban/community areas in the conterminous United States annually reduce electricity use by …
Quantifying Fish Habitat Associated With Stream Simulation Design Culverts In Northern Wisconsin, A. Timm, D. Higgins, J. Stanovick, R. Kolka, S. Eggert
Quantifying Fish Habitat Associated With Stream Simulation Design Culverts In Northern Wisconsin, A. Timm, D. Higgins, J. Stanovick, R. Kolka, S. Eggert
USDA Forest Service / UNL Faculty Publications
This study investigated the effects of culvert replacement design on fish habitat and fish weight by comparing substrate diversity and weight at three stream simulation (SS)-design and three bankfull and backwater (BB)-design sites on the Chequamegon-Nicolet National Forest, Wisconsin. Stream channel cross-sections, Wolman substrate particle counts, and single-pass backpack electro-fishing survey data were used to quantify fish habitat and fish weight in 50-m upstream and downstream sample reaches at each site. We applied generalized linear mixed models to test the hypothesis that substrate size and fish weight did not differ according to stream-crossing design type (SS or BB) and location …
Invasibility Of Three Major Non-Native Invasive Shrubs And Associated Factors In Upper Midwest U.S. Forest Lands, W. Keith Moser, Zhaofei Fan, Mark H. Hansen, Michael K. Crosby, Shirley X. Fan
Invasibility Of Three Major Non-Native Invasive Shrubs And Associated Factors In Upper Midwest U.S. Forest Lands, W. Keith Moser, Zhaofei Fan, Mark H. Hansen, Michael K. Crosby, Shirley X. Fan
USDA Forest Service / UNL Faculty Publications
We used non-native invasive plant data from the US Forest Service’s Forest Inventory and Analysis (FIA) program, spatial statistical methods, and the space (cover class)-for-time approach to quantify the invasion potential and success (‘‘invasibility”) of three major invasive shrubs (multiflora rose, non-native bush honeysuckles, and common buckthorn) in broadly classified forest-type groups in seven Upper Midwest states. Smoothed maps of presence and cover percent showed a strong clustering pattern for all three invasive shrubs despite their different ranges. The species are clustered around major cities or urban areas (e.g., Chicago, Illinois, and Des Moines, Iowa), indicating the potential role humans …
Semiochemicals In The Natural History Of Southern Pine Beetle Dendroctonus Frontalis Zimmermann And Their Role In Pest Management, B. T. Sullivan
Semiochemicals In The Natural History Of Southern Pine Beetle Dendroctonus Frontalis Zimmermann And Their Role In Pest Management, B. T. Sullivan
USDA Forest Service / UNL Faculty Publications
The southern pine beetle, Dendroctonus frontalis Zimmermann is generally considered to be one of the most significant biotic mortality agents of pines within North America, with a range stretching from New England to eastern Texas and from Arizona south to Nicaragua. As with other aggressive pine beetles, it relies on semiochemicals for coordinating the mass attacks necessary for colonization of healthy pines. Over the past 50 years its chemical ecology has received extensive study aimed at development of effective and practical semiochemical-based management strategies which might replace the destructive and costly techniques in practice. I review the literature on the …
Global Synthesis Of The Classifications, Distributions, Benefits And Issues Of Terracing, Wei Wei, Die Chen, Lixin Wang, Stefani Daryanto, Liding Chen, Yang Yu, Yonglong Lu, Ge Sun, Tianjiao Feng
Global Synthesis Of The Classifications, Distributions, Benefits And Issues Of Terracing, Wei Wei, Die Chen, Lixin Wang, Stefani Daryanto, Liding Chen, Yang Yu, Yonglong Lu, Ge Sun, Tianjiao Feng
USDA Forest Service / UNL Faculty Publications
For thousands of years, humans have created different types of terraces in different sloping conditions, meant to mitigate flood risks, reduce soil erosion and conserve water. These anthropogenic landscapes can be found in tropical and subtropical rainforests, deserts, and arid and semiarid mountains across the globe. Despite the long history, the roles of and the mechanisms by which terracing improves ecosystem services (ESs) remain poorly understood. Using literature synthesis and quantitative analysis, the worldwide types, distributions, major benefits and issues of terracing are presented in this review. A key terracing indicator, defined as the ratio of different ESs under terraced …
Conditions Inside Fisher Dens During Prescribed Fires; What Is The Risk Posed By Spring Underburns?, Craig M. Thompson, Kathryn L. Purcell
Conditions Inside Fisher Dens During Prescribed Fires; What Is The Risk Posed By Spring Underburns?, Craig M. Thompson, Kathryn L. Purcell
USDA Forest Service / UNL Faculty Publications
The use of spring prescribed fires to reduce accumulated fuel loads in western forests and facilitate the return of natural fire regimes is a controversial topic. While spring burns can be effective at reducing fuel loads and restoring heterogeneous landscapes, concerns exist over the potential impacts of unnaturally timed fires to native species. To protect native wildlife from disturbance during critical periods, limited operating periods (LOPs) are often implemented. However when LOPs for multiple species are combined into an integrated management plan, very few time windows for implementing prescribed fires remain. The use of spring burns is often effectively eliminated, …
Riparian Trees And Aridland Streams Of The Southwestern United States: An Assessment Of The Past, Present, And Future, D. Max Smith, Deborah M. Finch
Riparian Trees And Aridland Streams Of The Southwestern United States: An Assessment Of The Past, Present, And Future, D. Max Smith, Deborah M. Finch
USDA Forest Service / UNL Faculty Publications
Riparian ecosystems are vital components of aridlands within the southwestern United States. Historically, surface flows influenced population dynamics of native riparian trees. Many southwestern streams has been altered by regulation, however, and will be further affected by greenhouse warming. Our analysis of stream gage data revealed that decreases in volume of annual discharge and mean peak discharge and a shift to earlier peak discharge will occur in the Southern Rockies region of Colorado, New Mexico, and Utah. These changes will likely decrease rates of reproduction and survival of cottonwood (Populus fremontii and Populus deltoides ssp. wislizenii), Goodding's willow …
Review Of Broad-Scale Drought Monitoring Of Forests: Toward An Integrated Data Mining Approach, Steven P. Norman, Frank H. Koch, William W. Hargrove
Review Of Broad-Scale Drought Monitoring Of Forests: Toward An Integrated Data Mining Approach, Steven P. Norman, Frank H. Koch, William W. Hargrove
USDA Forest Service / UNL Faculty Publications
Efforts to monitor the broad-scale impacts of drought on forests often come up short. Drought is a direct stressor of forests as well as a driver of secondary disturbance agents, making a full accounting of drought impacts challenging. General impacts can be inferred from moisture deficits quantified using precipitation and temperature measurements. However, derived meteorological indices may not meaningfully capture drought impacts because drought responses can differ substantially among species, sites and regions. Meteorology-based approaches also require the characterization of current moisture conditions relative to some specified time and place, but defining baseline conditions over large, ecologically diverse regions can …
A Forest Vulnerability Index Based On Drought And High Temperatures, David Mildrexler, Zhiqiang Yang, Warren B. Cohen, David M. Bell
A Forest Vulnerability Index Based On Drought And High Temperatures, David Mildrexler, Zhiqiang Yang, Warren B. Cohen, David M. Bell
USDA Forest Service / UNL Faculty Publications
Increasing forest stress and tree mortality has been directly linked to combinations of drought and high temperatures. The climatic changes expected during the next decades – large increases in mean temperature, increased heat waves, and significant long-term regional drying in the western USA – will likely increase chronic forest stress and mortality. The aim of this research is to develop and apply a new forest vulnerability index (FVI) associated with drought and high temperatures across the Pacific Northwest region (PNW; Oregon and Washington) of the USA during the MODIS Aqua era (since 2003). Our technique incorporates the alterations to canopy …
Contributing Factors For Drought In United States Forest Ecosystems Under Projected Future Climates And Their Uncertainty, Charles H. Luce, James M. Vose, Neil Pederson, John Campbell, Connie Millar, Patrick Kormos, Ross Woods
Contributing Factors For Drought In United States Forest Ecosystems Under Projected Future Climates And Their Uncertainty, Charles H. Luce, James M. Vose, Neil Pederson, John Campbell, Connie Millar, Patrick Kormos, Ross Woods
USDA Forest Service / UNL Faculty Publications
Observations of increasing global forest die-off related to drought are leading to more questions about potential increases in drought occurrence, severity, and ecological consequence in the future. Dry soils and warm temperatures interact to affect trees during drought; so understanding shifting risks requires some understanding of changes in both temperature and precipitation. Unfortunately, strong precipitation uncertainties in climate models yield substantial uncertainty in projections of drought occurrence. We argue that disambiguation of drought effects into temperature and precipitation-mediated processes can alleviate some of the implied uncertainty. In particular, the disambiguation can clarify geographic diversity in forest sensitivity to multifarious drivers …
Improved Bulk Density Of Bamboo Pellets As Biomass For Energy Production, Zhijia Liu, Bingbing Mi, Zehui Jiang, Benhua Fei, Zhiyong Cai, Xing'e Liu
Improved Bulk Density Of Bamboo Pellets As Biomass For Energy Production, Zhijia Liu, Bingbing Mi, Zehui Jiang, Benhua Fei, Zhiyong Cai, Xing'e Liu
USDA Forest Service / UNL Faculty Publications
To the best of our knowledge, there is the lack of sufficient information concerning bamboo pellets. In the preliminary research, bamboo pellets showed a low bulk density which could not meet requirement of Pellet Fuels Institute Standard Specification for Residential/Commercial Densified (PFI). To improve its bulk density, pellets were manufactured using mixtures of bamboo and pine particles and the properties were investigated. It was found that adding pine particles to bamboo particles was an effective way to improve bulk density of bamboo pellets. When adding 40% pine particles to bamboo particles, bulk density of pellets increased from 0.54 …
Pronghorn Habitat Suitability In The Texas Panhandle, Nathan P. Duncan, Samantha S. Kahl, Shawn S. Gray, Christopher J. Salice, Richard D. Stevens
Pronghorn Habitat Suitability In The Texas Panhandle, Nathan P. Duncan, Samantha S. Kahl, Shawn S. Gray, Christopher J. Salice, Richard D. Stevens
USDA Forest Service / UNL Faculty Publications
Habitat quality is an important factor that can greatly affect wildlife populations. Pronghorn (Antilocapra americana) habitat in the Texas Panhandle, USA has been lost through growth of human settlements and agricultural lands. We determined the most pertinent environmental variables affecting habitat selection using multiple methods, including a search of peer-reviewed literature, expert opinion ranking, and habitat suitability modeling. We determined quality and extent of pronghorn habitat in the Texas Panhandle using the MAXENT modeling environment to build a presence-only habitat suitability model based on global positioning system (GPS) locations collected via aerial surveys. Our habitat suitability model indicated …
Pyrodiversity Promotes Avian Diversity Over The Decade Following Forest Fire, Morgan W. Tingley, Viviana Ruiz-Gutierrez, Robert L. Wilkerson, Christine A. Howell, Rodney B. Siegel
Pyrodiversity Promotes Avian Diversity Over The Decade Following Forest Fire, Morgan W. Tingley, Viviana Ruiz-Gutierrez, Robert L. Wilkerson, Christine A. Howell, Rodney B. Siegel
USDA Forest Service / UNL Faculty Publications
An emerging hypothesis in fire ecology is that pyrodiversity increases species diversity.We test whether pyrodiversity—defined as the standard deviation of fire severity—increases avian biodiversity at two spatial scales, and whether and how this relationship may change in the decade following fire. We use a dynamic Bayesian community model applied to a multi-year dataset of bird surveys at 1106 points sampled across 97 fires in montane California. Our results provide strong support for a positive relationship between pyrodiversity and bird diversity. This relationship interacts with time since fire, with pyrodiversity having a greater effect on biodiversity at 10 years post-fire than …
Ecosystem Services Of Woody Crop Production Systems, Ronald S. Zalesny Jr., John A. Stanturf, Emile S. Gardiner, James H. Perdue, Timothy M. Young, David R. Coyle, William L. Headlee, Gary S. Bañuelos, Amir Hass
Ecosystem Services Of Woody Crop Production Systems, Ronald S. Zalesny Jr., John A. Stanturf, Emile S. Gardiner, James H. Perdue, Timothy M. Young, David R. Coyle, William L. Headlee, Gary S. Bañuelos, Amir Hass
USDA Forest Service / UNL Faculty Publications
Short-rotation woody crops are an integral component of regional and national energy portfolios, as well as providing essential ecosystem services such as biomass supplies, carbon sinks, clean water, and healthy soils. We review recent USDA Forest Service Research and Development efforts from the USDA Biomass Research Centers on the provisioning of these ecosystem services from woody crop production systems. For biomass, we highlight productivity and yield potential, pest susceptibility, and bioenergy siting applications. We describe carbon storage in aboveground woody biomass and studies assessing the provision of clean and plentiful water. Soil protection and wildlife habitat are also mentioned, in …
Monthly Land Cover-Specific Evapotranspiration Models Derived From Global Eddy Flux Measurements And Remote Sensing Data, Yuan Fang, Ge Sun, Peter Caldwell, Steven G. Mcnulty, Asko Noormets, Jean-Christophe Domec, John King, Zhiqiang Zhang, Xudong Zhang, Guanghui Lin, Guangsheng Zhou, Jingfeng Xiao, Jiquan Chen
Monthly Land Cover-Specific Evapotranspiration Models Derived From Global Eddy Flux Measurements And Remote Sensing Data, Yuan Fang, Ge Sun, Peter Caldwell, Steven G. Mcnulty, Asko Noormets, Jean-Christophe Domec, John King, Zhiqiang Zhang, Xudong Zhang, Guanghui Lin, Guangsheng Zhou, Jingfeng Xiao, Jiquan Chen
USDA Forest Service / UNL Faculty Publications
Evapotranspiration (ET) is arguably the most uncertain ecohydrologic variable for quantifying watershed water budgets. Although numerous ET and hydrological models exist, accurately predicting the effects of global change on water use and availability remains challenging because of model deficiency and/or a lack of input parameters. The objective of this study was to create a new set of monthly ET models that can better quantify landscape-level ET with readily available meteorological and biophysical information. We integrated eddy covariance flux measurements from over 200 sites, multiple year remote sensing products from the Moderate Resolution Imaging Spectroradiometer (MODIS), and statistical modelling. Through examining …