Article
Entomology
Lauren Stead, Stephen B. Heard, Robert C. Johns
Summary: The spruce budworm is a significant pest in North American boreal forests, with females laying eggs on both balsam fir and black spruce. Parasitism rates and larval survival were shown to be higher on balsam fir than on black spruce, especially when larvae emerged synchronized with host budburst. This suggests that egg laying on both hosts may be a strategy to balance trade-offs between higher parasitism and foliage quality on different host species.
ECOLOGICAL ENTOMOLOGY
(2021)
Article
Biodiversity Conservation
Bastien Bellemin-Noel, Stephane Bourassa, Emma Despland, Louis De Grandpre, Deepa S. Pureswaran
Summary: Global warming can lead to phenological shifts that accelerate the development of eastern spruce budworm larvae and advance their pupation and budburst on black spruce and balsam fir. However, under higher temperatures, black spruce may become more susceptible to infestations, resulting in similar success rates for the budworm on both black spruce and balsam fir.
GLOBAL CHANGE BIOLOGY
(2021)
Article
Entomology
Christopher J. Greyson-Gaito, Sarah J. Dolson, Glen Forbes, Rosanna Lamb, Wayne E. MacKinnon, Kevin S. McCann, M. Alex Smith, Eldon S. Eveleigh
Summary: Eastern spruce budworm is a major pest of eastern North American forests, with outbreaks occurring every 30-40 years. Research has shown that higher hardwood content in forests can reduce defoliation and mortality of spruces during spruce budworm outbreaks. In this study, the use of phylogenetic community structure and stable isotope analysis revealed differences in the parasitoid community associated with spruce budworm in forest stands with different hardwood content. The study also found that the trophic relationships between parasitoids and caterpillars on balsam fir or hardwood trees changed within and between years.
AGRICULTURAL AND FOREST ENTOMOLOGY
(2022)
Article
Ecology
Hiromitsu Sato, Emeline Chaste, Martin P. Girardin, Jed O. Kaplan, Christelle Hely, Jean-Noel Candau, Stephen J. Mayor
Summary: The Eastern Spruce Budworm (ESBW) is a major disruptor in Canada's boreal forests, causing widespread defoliation and high mortality rates of fir and spruce trees. This can result in economic losses and increased fire potential. Our study presents a novel representation of host-specific defoliation in a Dynamic Global Vegetation Model (DGVM), which successfully simulates the spatiotemporal patterns of ESBW based on historical observations. We also analyzed the interaction between ESBW and wildfire, finding that wildfire is slightly enhanced after ESBW outbreaks due to increased fuel loads, particularly in drier regions.
ECOLOGICAL MODELLING
(2023)
Article
Ecology
Lorena Balducci, Philippe Rozenberg, Annie Deslauriers
Summary: Defoliation can have both positive and negative effects on tree growth and survival, with short-term benefits and long-term drawbacks. Understanding the impact of defoliation on stem radius variation during needle flushing can help elucidate the relationship between water use and tree growth. Conifers adjust their stem radius variation phases in response to defoliation severity over a 4-year period, indicating a reduced ability for recovery.
FRONTIERS IN FORESTS AND GLOBAL CHANGE
(2021)
Article
Agronomy
Abdelmadjid Djoumad, Philippe Tanguay, Jacques Regniere, Guylaine Trudel, Andrew Morrison, Cedric Fournier, Drew Carleton, Audrey Nisole, Don Stewart, Michel Cusson
Summary: This study demonstrates the feasibility of utilizing a molecular approach for counting L2s and assessing their natural enemy load using qPCR DNA quantification. The results show a strong correlation between DNA amount in larval extracts and the number of larvae, and molecular estimates of L2 counts are comparable to manual counting. Additionally, a TaqMan assay was used to monitor natural enemies present in the samples, with the proportion of affected individuals estimated through binomial probability distribution.
PEST MANAGEMENT SCIENCE
(2022)
Article
Geography, Physical
Rajeev Bhattarai, Parinaz Rahimzadeh-Bajgiran, Aaron Weiskittel, Aaron Meneghini, David A. MacLean
Summary: This study developed and evaluated new models using Sentinel-1 SAR and Sentinel-2 multispectral imagery combined with several site variables to map the distribution and abundance of SBW host species. The results indicate that Sentinel-2 multi-temporal single spectral bands and various spectral vegetation indices are effective for classifying SBW host species with high accuracy.
ISPRS JOURNAL OF PHOTOGRAMMETRY AND REMOTE SENSING
(2021)
Article
Ecology
Marion Germain, Daniel Kneeshaw, Louis De Grandpre, Melanie Desrochers, Patrick M. A. James, Udayalakshmi Vepakomma, Jean-Francois Poulin, Marc-Andre Villard
Summary: Three species of warblers, Tennessee, Cape May, and bay-breasted warbler, show positive responses to defoliation caused by spruce budworm outbreaks, with bay-breasted warbler consistently showing an increased presence 3-4 years before defoliation is detectable. This early response of bay-breasted warbler could be utilized for predicting future epicenters of spruce budworm outbreaks and targeting sampling efforts.
Article
Forestry
Philip Bell-Doyon, Virginie Bellavance, Louis Belanger, Marc J. Mazerolle, Juan Carlos A. Villarreal
Summary: The composition and diversity of soil microbiomes differ between old-growth and regenerating stands after either an insect outbreak or a clearcut, suggesting that the nature of stand-replacing disturbances influences the soil microbiome composition. The mechanisms underlying these differences remain unclear.
FOREST ECOLOGY AND MANAGEMENT
(2022)
Article
Entomology
Thanusha Suresh, Lucas E. E. Roscoe, N. Kirk Hillier
Summary: This study investigated the chemical ecology and behavioral responses of the spruce budworm to pheromones and host plant volatiles. Using single sensillum recordings (SSR), the researchers identified the responses of olfactory receptor neurons in the antennal sensilla to these stimuli. The study found that male and female budworms showed higher sensitivity to specific chemicals. Overall, these findings contribute to the improvement of integrated pest management strategies for the spruce budworm.
Article
Forestry
Joel D. Tremblay, Ronald F. Smith, Loic D'Orangeville
Summary: A study selected balsam fir trees suitable for Christmas tree breeding programs based on their desirable traits. Seven trees were identified as 'Select' trees that consistently maintained good needle retention and reduced moisture loss. These trees are being integrated into seed orchards to develop Christmas trees that can thrive in warm fall conditions. The results from this study will be used to assess the heritability of needle retention in the next generation of Christmas trees.
Article
Evolutionary Biology
Catherine Beliveau, Patrick Gagne, Sandrine Picq, Oksana Vernygora, Christopher Keeling, Kristine Pinkney, Daniel Doucet, Fayuan Wen, J. Spencer Johnston, Halim Maaroufi, Brian Boyle, Jerome Laroche, Ken Dewar, Nikoleta Juretic, Gwylim Blackburn, Audrey Nisole, Bryan Brunet, Marcelo Brandao, Lisa Lumley, Jun Duan, Guoxing Quan, Christopher J. Lucarotti, Amanda D. Roe, Felix A. H. Sperling, Roger C. Levesque, Michel Cusson
Summary: Insects, such as the spruce budworm, have developed antifreeze proteins (AFPs) to survive harsh winter conditions. A study on the genome of the budworm found that the genes responsible for AFPs were present in other related species as well, suggesting a common origin. The study also identified a zonadhesin-like protein that may have served as a precursor to tortricid AFPs.
GENOME BIOLOGY AND EVOLUTION
(2022)
Article
Plant Sciences
Barry J. Cooke, Louis-Etienne Robert, Brian R. Sturtevant, Dan Kneeshaw, Bina Thapa
Summary: This study investigates the impact of forest configuration and composition on the intensity of defoliator outbreaks in a mixedwood boreal forest. The results show that synchrony of outbreaks varies temporally and in direct proportion to cycle peak intensity. Additionally, the study finds a persistent negative spatial correlation among successive eruptive pulses of defoliation, indicating a contagious theory of eruption and outbreak spread.
JOURNAL OF ECOLOGY
(2023)
Article
Biochemistry & Molecular Biology
Skye Butterson, Amanda D. Roe, Katie E. Marshall
Summary: This study used the eastern spruce budworm as a model to investigate plasticity in cold hardiness, finding no evidence of transgenerational plasticity but evidence of local adaptation, especially in populations experiencing lower overwintering temperatures. These findings highlight the importance of phenotypic plasticity and local adaptation in modeling species distribution.
COMPARATIVE BIOCHEMISTRY AND PHYSIOLOGY A-MOLECULAR & INTEGRATIVE PHYSIOLOGY
(2021)
Article
Biochemistry & Molecular Biology
Mason T. MacDonald, Rajasekaran R. Lada, Gaye E. MacDonald, Claude D. Caldwell, Chibuike C. Udenigwe
Summary: This study uncovers lipid changes in balsam fir during cold acclimation and links those changes with postharvest needle abscission. Lipids such as DGDG, PC, PG, PE, and PA are strongly related to cold tolerance, with MGDG having the strongest relationship. The decrease in MGDG:DGDG ratio results in better cold tolerance and higher needle retention.
INTERNATIONAL JOURNAL OF MOLECULAR SCIENCES
(2023)
Article
Forestry
Mingke Li, David A. MacLean, Chris R. Hennigar, Jae Ogilvie
FOREST ECOLOGY AND MANAGEMENT
(2020)
Article
Forestry
Bo Zhang, David A. MacLean, Rob C. Johns, Eldon S. Eveleigh, Sara Edwards
FOREST ECOLOGY AND MANAGEMENT
(2020)
Review
Ecology
Jiban Chandra Deb, Graham Forbes, David A. MacLean
Article
Remote Sensing
Rajeev Bhattarai, Parinaz Rahimzadeh-Bajgiran, Aaron Weiskittel, David A. MacLean
REMOTE SENSING LETTERS
(2020)
Article
Forestry
Lance A. Vickers, Benjamin O. Knapp, John M. Kabrick, Laura S. Kenefic, Anthony W. D'Amato, Christel C. Kern, David A. MacLean, Patricia Raymond, Kenneth L. Clark, Daniel C. Dey, Nicole S. Rogers
Summary: Mixedwood forests in the northern United States cover a significant area and are most common in the Adirondack - New England, Laurentian, and Northeast ecological provinces. The presence of hardwood and softwood saplings indicates a potential shift towards hardwood dominance in the absence of disturbances.
CANADIAN JOURNAL OF FOREST RESEARCH
(2021)
Article
Geography, Physical
Rajeev Bhattarai, Parinaz Rahimzadeh-Bajgiran, Aaron Weiskittel, Aaron Meneghini, David A. MacLean
Summary: This study developed and evaluated new models using Sentinel-1 SAR and Sentinel-2 multispectral imagery combined with several site variables to map the distribution and abundance of SBW host species. The results indicate that Sentinel-2 multi-temporal single spectral bands and various spectral vegetation indices are effective for classifying SBW host species with high accuracy.
ISPRS JOURNAL OF PHOTOGRAMMETRY AND REMOTE SENSING
(2021)
Article
Environmental Sciences
Shawn D. Donovan, David A. MacLean, Yun Zhang, Michael B. Lavigne, John A. Kershaw
Summary: This study introduced a new method for estimating annual spruce budworm defoliation using change detection of vegetation indices derived from satellite hyperspectral imagery. The accuracy of classifying defoliation using this method was significantly higher than that of aerial surveys.
REMOTE SENSING OF ENVIRONMENT
(2021)
Review
Forestry
David A. MacLean, Kenneth L. Clark
Summary: Mixedwood stands, composed of hardwoods and softwoods, provide greater resistance and resilience to forests when stressed or disturbed by insect infestations. Incorporating mixedwood management strategies can help minimize economic losses associated with tree mortality and mitigate short-term impacts to ecosystem functioning resulting from insect damage, especially carbon sequestration, in the face of projected increases in insect infestations associated with changing climate.
CANADIAN JOURNAL OF FOREST RESEARCH
(2021)
Article
Forestry
William R. Vaughn, Anthony R. Taylor, David A. MacLean, Loic D'Orangeville
Summary: This study examines the response of seed germination success to projected winter warming in Canada's Acadian Forest Region. The results suggest that tested tree species are not significantly affected by the warming and there are variations in the response among different seedlots.
CANADIAN JOURNAL OF FOREST RESEARCH
(2022)
Article
Forestry
William R. Vaughn, Anthony R. Taylor, David A. MacLean, Loic D'Orangeville, Michael B. Lavigne
Summary: In this study, the growth and survival of balsam fir, red spruce, and red maple seedlings were assessed under warming, drought, and elevated CO2 conditions. The study found that while red spruce showed positive responses to warming, red maple exhibited greater growth and survival rates compared to the conifers, and balsam fir was less adapted to warming and drought. CO2 enrichment mitigated the negative effects of drought on seedling growth.
CANADIAN JOURNAL OF FOREST RESEARCH
(2021)
Review
Environmental Sciences
David A. MacLean, Anthony R. Taylor, Peter D. Neily, James W. N. Steenberg, Sean P. Basquill, Eugene Quigley, Celia K. Boone, Morgan Oikle, Peter Bush, Bruce Stewart
Summary: This study reviewed the natural disturbance regimes of forests in Nova Scotia, Canada, and proposed an approach to guide ecological forestry based on these regimes. By considering different disturbance agents and the ecological land classification, target harvest rotations and stand structures were determined. This approach can be applied in any region with a strong ecological land classification system and multiple disturbance agents.
ENVIRONMENTAL REVIEWS
(2022)
Article
Plant Sciences
Jiban Chandra Deb, Shane Furze, David A. MacLean
Summary: Understory vascular plant species are important in maintaining nutrient balances and providing food, but they are facing potential extirpation due to human interventions. The influence of different environmental variables on the distribution of vascular plant communities remains unclear.
Review
Forestry
Joe Collier, David A. MacLean, Loic D'Orangeville, Anthony R. Taylor
Summary: The effects of climate change on balsam fir regeneration may be more gradual than projected, primarily occurring through reduced competitive ability and increased mortality in overstory trees rather than regeneration failure.
FORESTRY CHRONICLE
(2022)
Article
Forestry
Zelin Liu, Changhui Peng, David A. MacLean, Louis De Grandpre, Jean-Noel Candau, Daniel Kneeshaw
Summary: The impact of early intervention strategy (EIS) and foliage protection strategy (FP) on forest carbon (C) dynamics during spruce budworm outbreaks is still unclear. This study found that applying FP in the areas with the greatest potential C losses resulted in a greater reduction in cumulative net ecosystem productivity (NEP) than a higher proportion of FP. Successful implementation of EIS for 12 years can maintain more forest C than FP applied everywhere. The effectiveness of treatments during spruce budworm outbreaks depends on forest species, age, and their interactions.
Article
Forestry
Nicholas C. Coops, Alexis Achim, Paul Arp, Christopher W. Bater, John P. Caspersen, Jean-Francois Cote, Jeffery P. Dech, Adam R. Dick, Karin van Ewijk, Richard Fournier, Tristan R. H. Goodbody, Chris R. Hennigar, Antoine Leboeuf, Olivier R. van Lier, Joan E. Luther, David A. MacLean, Grant McCartney, Gaetan Pelletier, Jean-Francois Prieur, Piotr Tompalski, Paul M. Treitz, Joanne C. White, Murray E. Woods
Summary: The AWARE project, a five-year collaboration involving universities, forest companies, and forestry agencies, aimed to enhance the characterization of Canadian forests using remote sensing technologies. Supported researchers examined the role of advanced remote sensing technologies in the development of accurate forest inventory systems.
FORESTRY CHRONICLE
(2021)