Article
Forestry
Kelly M. McDonald, John R. Seiler, Bingxue Wang, Scott M. Salom, Rusty J. Rhea
Summary: The introduction of hemlock woolly adelgid has caused widespread mortality in eastern hemlock forests in the United States, threatening millions of hectares of these forests. The adelgid feeds on needles and reduces leaf-level physiology, leading to tree decline. This study investigated the leaf physiology of hemlocks at three forested sites with varying degrees of infestation. Treatment with imidacloprid, a commonly used control for adelgid, resulted in increased photosynthetic rates and stomatal conductance after one growing season. After two years, imidacloprid treatment also increased bud break and chlorophyll fluorescence. These findings suggest that adelgid-induced tree mortality is primarily due to reduced leaf area caused by decreased bud break, as well as a slight reduction in leaf-level photosynthesis and stomatal conductance.
Article
Biotechnology & Applied Microbiology
Albert E. Mayfield Iii, Tonya D. Bittner, Nicholas J. Dietschler, Joseph S. Elkinton, Nathan P. Havill, Melody A. Keena, David L. Mausel, James R. Rhea, Scott M. Salom, Mark C. Whitmore
Summary: The hemlock woolly adelgid (HWA) is an invasive insect that poses a threat to the ecological function of eastern hemlock and Carolina hemlock in eastern North American forests. Efforts to control HWA through the introduction of predator insects from Asia and western North America have had limited success. Recent research has focused on specific genetic lineages of parasitic flies that show promise for establishment in eastern North America.
BIOLOGICAL CONTROL
(2023)
Article
Biotechnology & Applied Microbiology
Hannah M. Thompson, Gregory Wiggins, Suzanne Lenhart
Summary: This study constructs a model to examine the joint impact of the invasive insect pest hemlock woolly adelgid and two introduced predator species on hemlock populations. The results show that the presence of predators can reduce adelgid densities and that the model allows for predator coexistence in natural settings.
BIOLOGICAL CONTROL
(2022)
Article
Biodiversity Conservation
Bruna R. Amaral, Andrew M. Wilson, Julie Blum, David A. Miller
Summary: Eastern hemlock forests in eastern North America are threatened by the invasive hemlock woolly adelgid. Although the negative effects of adelgid invasion on local bird communities have been documented, its regional impacts have not been quantified. This study used spatial and temporal databases to estimate the effects of adelgid infestation on bird species' demographic trends, and found significant declines in abundance for hemlock-associated bird species after infestation. However, these declines were not as universal at a broad spatiotemporal scale compared to local studies, suggesting that spatial heterogeneity may buffer them.
BIOLOGICAL INVASIONS
(2023)
Article
Ecology
Hannah M. Thompson, Thomas J. McAvoy, Gregory Wiggins, Scott M. Salom, Suzanne Lenhart
Summary: The hemlock woolly adelgid (Adelges tsugae Annand) is an invasive insect pest that causes significant changes to hemlock forests in the eastern United States. An infestation of A. tsugae often leads to the death of eastern hemlock (Tsuga canadensis) within years. A model composed of systems of ordinary differential equations with time-dependent parameters is used to investigate the mechanisms behind cycles in hemlock health and A. tsugae density.
Article
Entomology
Carrie S. Jubb, Thomas J. McAvoy, Kari E. Stanley, Ariel R. Heminger, Scott M. Salom
Summary: The study demonstrated that Laricobius nigrinus successfully established at 82% of release sites in Virginia and was the primary species recovered. While stand-level HWA densities varied greatly over sites and years, they showed a general decline over the course of the study.
Article
Ecology
Ryan S. Crandall, Jeffrey A. Lombardo, Joseph S. Elkinton
Summary: The density of insect herbivores is regulated by top-down factors (e.g., natural enemies) and bottom-up effects (e.g., plant defenses against herbivory). In the case of the hemlock woolly adelgid (HWA), top-down control from predators was found to be more important than bottom-up control from plant resistance. This finding supports the validity of the biological control program for HWA in reducing outbreak populations.
Article
Forestry
Mary Ann Fajvan, Andrea Hille
Summary: Pre-emptive silvicultural treatments can improve the health of eastern hemlock forests and reduce the vulnerability to hemlock woolly adelgid. Increasing canopy light exposure through thinning can help mitigate the impact of the invasive species.
CANADIAN JOURNAL OF FOREST RESEARCH
(2023)
Article
Biodiversity Conservation
Natalie M. Bekins, David R. Brown
Summary: Chemical treatments have a positive effect on individual hemlocks but do not significantly impact avian species. The health of hemlocks may need to decline to a certain threshold before avian species respond.
NORTHEASTERN NATURALIST
(2022)
Article
Forestry
Austin Thomas, David C. Tilotta, John Frampton, Robert M. Jetton
Summary: Fraser fir, a tree endemic to the Southern Appalachians, is threatened by the introduced balsam woolly adelgid. This study identifies foliar terpenoids associated with adelgid infestations and suggests their potential use as indicators for resistance in future breeding programs.
Article
Entomology
Meg Sanders, Renee Tardani, Alexandra Locher, Kathryn Geller, Charlyn G. Partridge
Summary: The study aimed to find an affordable and efficient trap for early monitoring of hemlock woolly adelgid (HWA). The researchers found that the modified motorized trap showed good results in capturing HWA. Overall, the number of traps, elevation, and distance to infested hemlocks affected the capture success rate.
JOURNAL OF ECONOMIC ENTOMOLOGY
(2023)
Article
Forestry
Mary Ann Fajvan, Randall S. Morin
Summary: Landscape-scale maps of tree species densities are important for ecosystem management, especially in the case of threatened forests. Hemlock, a dominant species in riparian forests, plays a crucial ecohydrological role in deciduous landscapes. The spread of the nonnative hemlock woolly adelgid has led to widespread hemlock decline and mortality, prompting the need for identifying and prioritizing areas for supplemental conifer planting.
JOURNAL OF FORESTRY
(2021)
Article
Forestry
Gina A. Davis, Laura Lowrey, Tom Eckberg, Jeffrey A. Hicke, Ekaterina Smirnova
Summary: This study investigates the infestation and effects of the Balsam woolly adelgid (BWA) on host trees in Idaho. The presence of BWA increased across most sites regardless of host species. BWA causes severe damage and mortality of true fir, impacting tree diameter growth and age. This assessment provides baseline data for further analysis of insect, host, stand, and environmental interactions.
JOURNAL OF FORESTRY
(2022)
Article
Forestry
Chris J. Peterson
Summary: This study documented trends in aboveground biomass and carbon over 10 years of forest recovery after a severe wind disturbance in a Tsuga canadensis-Pinus strobus forest in northwest Connecticut, USA. The results showed that biomass and carbon accumulation were faster than in similar forests with similar wind disturbance severity, and there was an increase in species diversity of woody stems after 10 years.
Article
Forestry
Matthew S. VanderMolen, Christopher R. Webster
Summary: The study finds that deer herbivory significantly impacts tree regeneration in the forest, particularly for browse-sensitive species. The treatment effects of deer exclosures and gap size can alter regeneration trajectories.
FOREST ECOLOGY AND MANAGEMENT
(2021)
Article
Geosciences, Multidisciplinary
Daniel Sousa, Joshua B. Fisher, Fernando Romero Galvan, Ryan P. Pavlick, Susan Cordell, Thomas W. Giambelluca, Christian P. Giardina, Gregory S. Gilbert, Faith Imran-Narahari, Creighton M. Litton, James A. Lutz, Malcolm P. North, David A. Orwig, Rebecca Ostertag, Lawren Sack, Richard P. Phillips
Summary: Imaging spectroscopy technology can improve maps of tree-mycorrhizal associations by capturing accurate ground truth observations through forest canopy signals. This approach could greatly enhance the spatial precision of mycorrhizal distributions globally and facilitate the incorporation of dynamic shifts in forest composition into Earth system models.
GEOPHYSICAL RESEARCH LETTERS
(2021)
Article
Plant Sciences
Peter B. Boucher, Ian Paynter, David A. Orwig, Ilan Valencius, Crystal Schaaf
Summary: The research evaluated the impact of occlusion on TLS scans and compared different stem sets, finding that occlusion from non-stem sources was the major influence on TLS line of sight. It was also discovered that transect and point TLS samples demonstrated better representativeness of some stem properties. Deriving sampled area from TLS scans improved estimates of stem density.
Article
Ecology
Mustafa Saifuddin, Jennifer M. Bhatnagar, Richard P. Phillips, Adrien C. Finzi
Summary: Microbial processes are central in regulating nitrogen availability in temperate forests, but the relationship between microbial community structure and nitrogen cycle fluxes is complex. This study found that nitrogen availability and flux rates vary across mycorrhizal gradients, with stands dominated by trees associated with arbuscular mycorrhizal fungi showing higher rates of nitrogen fixation and denitrification. However, changes in mycorrhizal dominance may impact nitrogen cycling independent of shifts in the abundance of nitrogen-cycling bacteria.
Article
Multidisciplinary Sciences
Yonglin Zhong, Chengjin Chu, Jonathan A. Myers, Gregory S. Gilbert, James A. Lutz, Jonas Stillhard, Kai Zhu, Jill Thompson, Jennifer L. Baltzer, Fangliang He, Joseph A. LaManna, Stuart J. Davies, Kristina J. Aderson-Teixeira, David F. R. P. Burslem, Alfonso Alonso, Kuo-Jung Chao, Xugao Wang, Lianming Gao, David A. Orwig, Xue Yin, Xinghua Sui, Zhiyao Su, Iveren Abiem, Pulcherie Bissiengou, Norm Bourg, Nathalie Butt, Min Cao, Chia-Hao Chang-Yang, Wei-Chun Chao, Hazel Chapman, Yu-Yun Chen, David A. Coomes, Susan Cordell, Alexandre A. de Oliveira, Hu Du, Suqin Fang, Christian P. Giardina, Zhanqing Hao, Andrew Hector, Stephen P. Hubbell, David Janik, Patrick A. Jansen, Mingxi Jiang, Guangze Jin, David Kenfack, Kamil Kral, Andrew J. Larson, Buhang Li, Xiankun Li, Yide Li, Juyu Lian, Luxiang Lin, Feng Liu, Yankun Liu, Yu Liu, Fuchen Luan, Yahuang Luo, Keping Ma, Yadvinder Malhi, Sean M. McMahon, William McShea, Herve Memiaghe, Xiangcheng Mi, Mike Morecroft, Vojtech Novotny, Michael J. O'Brien, Jan den Ouden, Geoffrey G. Parker, Xiujuan Qiao, Haibao Ren, Glen Reynolds, Pavel Samonil, Weiguo Sang, Guochun Shen, Zhiqiang Shen, Guo-Zhang Michael Song, I-Fang Sun, Hui Tang, Songyan Tian, Amanda L. Uowolo, Maria Uriarte, Bin Wang, Xihua Wang, Youshi Wang, George D. Weiblen, Zhihong Wu, Nianxun Xi, Wusheng Xiang, Han Xu, Kun Xu, Wanhui Ye, Mingjian Yu, Fuping Zeng, Minhua Zhang, Yingming Zhang, Li Zhu, Jess K. Zimmerman
Summary: The study found that arbuscular mycorrhizal (AM) trees predominantly contribute to decreasing total beta-diversity, reducing turnover, and increasing nestedness with increasing latitude, while the wide distributions of ectomycorrhizal (EcM) trees do not generate strong compositional differences among localities. Environmental variables, especially temperature and precipitation, are strongly correlated with beta-diversity patterns for AM trees and all trees, rather than for EcM trees.
NATURE COMMUNICATIONS
(2021)
Article
Ecology
Tim Rademacher, Bijan Seyednasrollah, David J. Basler, Jian Cheng, Tessa Mandra, Elise Miller, Zuid Lin, David A. Orwig, Neil Pederson, Hanspeter Pfister, Donglai Wei, Li Yao, Andrew D. Richardson
Summary: Ecological data collection and sharing are accelerating, but often in inconsistent and untraceable forms, while wood images contain valuable information. WIAD is an open-source application that provides user-friendly tools for visual analysis and archiving of wood samples, aiming to enhance transparency and reproducibility in ecological studies utilizing visual characteristics of wood.
METHODS IN ECOLOGY AND EVOLUTION
(2021)
Article
Ecology
Jonathan R. Holt, Jennifer R. Smetzer, Mark E. Borsuk, Danelle Laflower, David A. Orwig, Jonathan R. Thompson
Summary: Invasive forest insects have significant impacts on forest ecosystems and forest landowners. This study found that the detection of highly impactful emerald ash borer (EAB) decreases the probability of harvest but increases the intensity of harvest, resulting in a net increase in harvested biomass. Furthermore, EAB detection influences private landowners to harvest greater quantities of ash and affects the diameter of harvested trees.
ECOLOGICAL APPLICATIONS
(2022)
Article
Entomology
Jennifer L. Chandler, Joseph S. Elkinton, David A. Orwig
Summary: This article introduces the widespread mortality of Carolina and eastern hemlock caused by Hemlock woolly adelgid (HWA) in the eastern United States, and investigates the reasons behind the decline in HWA density in 2018. The study finds an indirect relationship between high rainfall and regional HWA decline, which may contribute to better prediction of HWA population dynamics.
ENVIRONMENTAL ENTOMOLOGY
(2022)
Article
Ecology
Erika Gonzalez-Akre, Camille Piponiot, Mauro Lepore, Valentine Herrmann, James A. Lutz, Jennifer L. Baltzer, Christopher W. Dick, Gregory S. Gilbert, Fangliang He, Michael Heym, Alejandra Huerta, Patrick A. Jansen, Daniel J. Johnson, Nikolai Knapp, Kamil Kral, Dunmei Lin, Yadvinder Malhi, Sean M. McMahon, Jonathan A. Myers, David Orwig, Diego Rodriguez-Hernandez, Sabrina E. Russo, Jessica Shue, Xugao Wang, Amy Wolf, Tonghui Yang, Stuart J. Davies, Kristina J. Anderson-Teixeira
Summary: The study introduces a new integrated R package, allodb, containing a wide range of allometric equations and functions for calculating tree above-ground biomass across the global extratropics. Based on ForestGEO forest dynamics plots data, the equation dataset can be customized and expanded for different forest types.
METHODS IN ECOLOGY AND EVOLUTION
(2022)
Article
Multidisciplinary Sciences
David A. Orwig, Jason A. Aylward, Hannah L. Buckley, Bradley S. Case, Aaron M. Ellison
Summary: Land-use history has a lasting impact on the composition and structure of plant and tree populations, with soil type, neighborhood effects, and past land-use history being the main factors influencing the distribution and abundance of present-day tree species.
Article
Ecology
Xiaoshu Li, Kevin J. Boyle, Evan L. Preisser, Thomas P. Holmes, David Orwig
Summary: This study investigates the impact of the spread of the Hemlock wooly adelgid infestation on residential property prices in central Connecticut and Massachusetts, USA. The results show that the presence of hemlock trees and adelgid infestation within 0.1 km buffers of properties affects sale prices, but this effect does not extend to buffers of 0.5 and 1.0 km's. Within the 0.1 km buffer, only healthy hemlock trees contribute positively to property values.
ECOLOGICAL ECONOMICS
(2022)
Review
Environmental Sciences
Cecelia M. Gerstenbacher, Adrien C. Finzi, Randi D. Rotjan, Alyssa B. Novak
Summary: Microplastics have potential impacts on seagrass plants, epiphytes, and sediment processes and functions. They may harm seagrasses and epiphytes through impalement and light/gas blockage, increase toxin concentrations, and disrupt nutrient cycling and sediment characteristics.
ENVIRONMENTAL POLLUTION
(2022)
Article
Environmental Sciences
Laura Duncanson, James R. Kellner, John Armston, Ralph Dubayah, David M. Minor, Steven Hancock, Sean P. Healey, Paul L. Patterson, Svetlana Saarela, Suzanne Marselis, Carlos E. Silva, Jamis Bruening, Scott J. Goetz, Hao Tang, Michelle Hofton, Bryan Blair, Scott Luthcke, Lola Fatoyinbo, Katharine Abernethy, Alfonso Alonso, Hans-Erik Andersen, Paul Aplin, Timothy R. Baker, Nicolas Barbier, Jean Francois Bastin, Peter Biber, Pascal Boeckx, Jan Bogaert, Luigi Boschetti, Peter Brehm Boucher, Doreen S. Boyd, David F. R. P. Burslem, Sofia Calvo-Rodriguez, Jerome Chave, Robin L. Chazdon, David B. Clark, Deborah A. Clark, Warren B. Cohen, David A. Coomes, Piermaria Corona, K. C. Cushman, Mark E. J. Cutler, James W. Dalling, Michele Dalponte, Jonathan Dash, Sergio de-Miguel, Songqiu Deng, Peter Woods Ellis, Barend Erasmus, Patrick A. Fekety, Alfredo Fernandez-Landa, Antonio Ferraz, Rico Fischer, Adrian G. Fisher, Antonio Garcia-Abril, Terje Gobakken, Jorg M. Hacker, Marco Heurich, Ross A. Hill, Chris Hopkinson, Huabing Huang, Stephen P. Hubbell, Andrew T. Hudak, Andreas Huth, Benedikt Imbach, Kathryn J. Jeffery, Masato Katoh, Elizabeth Kearsley, David Kenfack, Natascha Kljun, Nikolai Knapp, Kamil Kral, Martin Krucek, Nicolas Labriere, Simon L. Lewis, Marcos Longo, Richard M. Lucas, Russell Main, Jose A. Manzanera, Rodolfo Vasquez Martinez, Renaud Mathieu, Herve Memiaghe, Victoria Meyer, Abel Monteagudo Mendoza, Alessandra Monerris, Paul Montesano, Felix Morsdorf, Erik Naesset, Laven Naidoo, Reuben Nilus, Michael O'Brien, David A. Orwig, Konstantinos Papathanassiou, Geoffrey Parker, Christopher Philipson, Oliver L. Phillips, Jan Pisek, John R. Poulsen, Hans Pretzsch, Christoph Rudiger, Sassan Saatchi, Arturo Sanchez-Azofeifa, Nuria Sanchez-Lopez, Robert Scholes, Carlos A. Silva, Marc Simard, Andrew Skidmore, Krzysztof Sterenczak, Mihai Tanase, Chiara Torresan, Ruben Valbuena, Hans Verbeeck, Tomas Vrska, Konrad Wessels, Joanne C. White, Lee J. T. White, Eliakimu Zahabu, Carlo Zgraggen
Summary: This paper presents the development of models used by NASA's Global Ecosystem Dynamics Investigation (GEDI) to estimate forest aboveground biomass density (AGBD). The models were developed using globally distributed field and airborne lidar data, with simulated relative height metrics as predictor variables. The study found that stratification by geographic domain and the use of square root transformation improved model performance.
REMOTE SENSING OF ENVIRONMENT
(2022)
Article
Ecology
Fiona Jevon, Dayna De la Cruz, Joseph A. LaManna, Ashley K. Lang, David A. Orwig, Sydne Record, Paige Kouba, Matthew P. Ayres, Jaclyn Hatala Matthes
Summary: Conspecific negative density dependence promotes tree species diversity in temperate forests and is related to tree species traits and ecological attributes.
Article
Ecology
Melannie D. Hartman, Mark Burnham, William J. Parton, Adrien Finzi, Evan H. DeLucia, Wendy H. Yang
Summary: This study used a modeling approach to evaluate the effectiveness of nitrification suppression by sorghum in reducing N2O emissions and nitrate leaching in an energy sorghum/soybean rotation. The results showed that nitrification suppression had a modest effect on reducing N2O emissions, but had little impact on nitrate leaching. Altering the timing of fertilizer applications to synchronize with high soil ammonium levels had mixed effects on N losses. Increasing N retention during the non-growing season may be more effective for reducing annual N losses in the rainfed Midwest.
Article
Forestry
Loic D'Orangeville, Malcolm Itter, Dan Kneeshaw, J. William Munger, Andrew D. Richardson, James M. Dyer, David A. Orwig, Yude Pan, Neil Pederson
Summary: Climate models project that hotter droughts will have critical impacts on tree growth and forest dynamics in temperate forests of Eastern North America. Our study highlights the importance of wood porosity as a predictor of species climatic sensitivity to the projected intensification of the drought regime.