scholarly journals Positive Results of an Early Intervention Strategy to Suppress a Spruce Budworm Outbreak after Five Years of Trials

Forests ◽  
2019 ◽  
Vol 10 (5) ◽  
pp. 448 ◽  
Author(s):  
David A. MacLean ◽  
Peter Amirault ◽  
Luke Amos-Binks ◽  
Drew Carleton ◽  
Chris Hennigar ◽  
...  
Keyword(s):  
Early Intervention ◽  
New Brunswick ◽  
Choristoneura Fumiferana ◽  
Intervention Strategy ◽  
Abies Balsamea ◽  
Spruce Budworm ◽  
Treatment Programs ◽  
Native Forest ◽  
Insecticide Treatment ◽  
Salvage Harvesting

Spruce budworm (Choristoneura fumiferana Clem.; SBW) outbreaks are one of the dominant natural disturbances in North America, having killed balsam fir (Abies balsamea (L.) Mill.) and spruce (Picea sp.) trees over tens of millions of hectares. Responses to past SBW outbreaks have included the aerial application of insecticides to limit defoliation and keep trees alive, salvage harvesting of dead and dying trees, or doing nothing and accepting the resulting timber losses. We tested a new ‘early intervention strategy’ (EIS) focused on suppressing rising SBW populations before major defoliation occurs, from 2014 to 2018 in New Brunswick, Canada. The EIS approach included: (1) intensive monitoring of overwintering SBW to detect ‘hot spots’ of low but rising populations; (2) targeted insecticide treatment to prevent spread; and (3) proactive public communications and engagement on project activities and results. This is the first attempt of area-wide (all areas within the jurisdiction of the province of New Brunswick) management of a native forest insect population. The project was conducted by a consortium of government, forest industry, researchers, and other partners. We developed a treatment priority and blocking model to optimize planning and efficacy of EIS SBW insecticide treatment programs. Following 5 years of over 420,000 ha of EIS treatments of low but increasing SBW populations, second instar larvae (L2) SBW levels across northern New Brunswick were found to be considerably lower than populations in adjacent Québec. Treatments increased from 4500 ha in 2014, to 56,600 ha in 2016, and to 199,000 ha in 2018. SBW populations in blocks treated with Bacillus thuringiensis or tebufenozide insecticide were consistently reduced, and generally did not require treatment in the subsequent year. Areas requiring treatment increased up to 2018, but SBW L2 populations showed over 90% reductions in that year. Although this may be a temporary annual decline in SBW population increases, it is counter to continued increases in Québec. Following 5 years of tests, the EIS appears to be effective in reducing the SBW outbreak.

scholarly journals A Conceptual Framework for the Spruce Budworm Early Intervention Strategy: Can Outbreaks be Stopped?

Forests ◽  
2019 ◽  
Vol 10 (10) ◽  
pp. 910 ◽  
Author(s):  
Robert C. Johns ◽  
Joseph J. Bowden ◽  
Drew R. Carleton ◽  
Barry J. Cooke ◽  
Sara Edwards ◽  
...  
Keyword(s):  
Early Intervention ◽  
Conceptual Framework ◽  
Population Control ◽  
Choristoneura Fumiferana ◽  
Intervention Strategy ◽  
Abies Balsamea ◽  
Cost Benefit ◽  
Leading Edge ◽  
Spruce Budworm ◽  
Management Program

The spruce budworm, Choristoneura fumiferana, Clem., is the most significant defoliating pest of boreal balsam fir (Abies balsamea (L.) Mill.) and spruce (Picea sp.) in North America. Historically, spruce budworm outbreaks have been managed via a reactive, foliage protection approach focused on keeping trees alive rather than stopping the outbreak. However, recent theoretical and technical advances have renewed interest in proactive population control to reduce outbreak spread and magnitude, i.e., the Early Intervention Strategy (EIS). In essence, EIS is an area-wide management program premised on detecting and controlling rising spruce budworm populations (hotspots) along the leading edge of an outbreak. In this article, we lay out the conceptual framework for EIS, including all of the core components needed for such a program to be viable. We outline the competing hypotheses of spruce budworm population dynamics and discuss their implications for how we manage outbreaks. We also discuss the practical needs for such a program to be successful (e.g., hotspot monitoring, population control, and cost–benefit analyses), as well as the importance of proactive communications with stakeholders.

scholarly journals Economics of Early Intervention to Suppress a Potential Spruce Budworm Outbreak on Crown Land in New Brunswick, Canada

Forests ◽  
2019 ◽  
Vol 10 (6) ◽  
pp. 481 ◽  
Author(s):  
Eric Ye Liu ◽  
Van A. Lantz ◽  
David A. MacLean ◽  
Chris Hennigar
Keyword(s):  
Early Intervention ◽  
New Brunswick ◽  
Computable General Equilibrium ◽  
Choristoneura Fumiferana ◽  
Intervention Strategy ◽  
Spruce Budworm ◽  
Timber Harvest ◽  
Economic Output ◽  
Biological Insecticide ◽  
Protection Strategies

We investigated the potential economic impacts of future spruce budworm (Choristoneura fumiferana Clem.) (SBW) outbreaks on 2.8 million ha of Crown land in New Brunswick, Canada and compared an early intervention strategy (EIS) with foliage protection approaches. We coupled the Spruce Budworm Decision Support System (SBW DSS) with a Computable General Equilibrium (CGE) model to assess the impacts of EIS and foliage protection on 0%, 5%, 10%, and 20% of susceptible Crown (publicly owned) forest, under moderate and severe SBW outbreak scenarios. Cumulative available harvest supply from 2017 to 2067 was projected to be reduced by 29 to 43 million m3, depending upon SBW outbreak severity, and a successful EIS approach would prevent this loss. These harvest reductions were projected to reduce total economic output by $25 billion (CAD) to $35 billion. Scenarios using biological insecticide foliage protection over 20% of susceptible Crown forest area were projected to reduce losses to 6–17 million m3 and $0.5–4.1 billion. Depending upon SBW outbreak severity, EIS was projected to have benefit/cost ratios of 3.8 to 6.4 and net present values of $186 million to $353 million, both higher than foliage protection strategies. Sensitivity analysis scenarios of ‘what if’ EIS partially works (80% or 90%) showed that these produced superior timber harvest savings than the best foliage protection scenario under severe SBW outbreak conditions and generally superior results under moderate outbreak scenarios. Overall, results support the continued use of EIS as the preferred strategy on economic grounds to protect against SBW outbreaks on Crown land in New Brunswick.

Windthrow and growth response following a spruce budworm inspired, variable retention harvest in New Brunswick, Canada

2015 ◽  
Vol 45 (6) ◽  
pp. 659-666 ◽  
Author(s):  
Edward A. Wilson ◽  
David A. MacLean
Keyword(s):  
New Brunswick ◽  
Growth Response ◽  
Choristoneura Fumiferana ◽  
Abies Balsamea ◽  
Natural Disturbance ◽  
Spruce Budworm ◽  
Balsam Fir ◽  
Growth Release ◽  
Variable Retention ◽  
Variable Retention Harvest

Forest management regimes increasingly focus on the emulation of natural disturbance events, e.g., fire or insect outbreaks, to help increase ecosystem sustainability. We determined the residual stand response to a variable retention harvest inspired by spruce budworm (Choristoneura fumiferana (Clemens)) outbreaks in New Brunswick, Canada. Our objectives were to analyze the differences between surviving residual trees and those that succumbed to windthrow and to quantify growth release. The treatment was based on harvesting the estimated spruce budworm outbreak mortality, i.e., 90% of mature balsam fir (Abies balsamea (L.) Mill., 60% of mature spruce (Picea spp.), and no hardwoods. Windthrow increased with the proportion of trees harvested and averaged 52% over 7–9 years in these stands with high balsam fir – spruce content. One-third of 42 harvested plots sustained >30% windthrow, whereas 73% of 11 similar unharvested plots had <10% windthrow. Balsam fir had higher windthrow than spruce at 53% and 41%, respectively. Windthrown balsam fir trees had significantly larger diameters at breast height (DBH, 1.3 m), larger heights, and smaller crown ratios than surviving residual trees. Substantial growth release occurred, with DBH increment of residual trees 48%–64% greater than trees in unharvested plots. Balsam fir and intolerant hardwoods exhibited the largest growth response. We suggest that future spruce budworm inspired harvests in stands with high balsam fir – spruce content use two or three entries about 5 years apart to reduce windthrow.

Re-examining wood supply in light of future spruce budworm outbreaks: A case study in New Brunswick

2013 ◽  
Vol 89 (01) ◽  
pp. 42-53 ◽  
Author(s):  
C.R. Hennigar ◽  
T.A. Erdle ◽  
J.J. Gullison ◽  
D.A. MacLean
Keyword(s):  
New Brunswick ◽  
Choristoneura Fumiferana ◽  
Spruce Budworm ◽  
Mitigation Strategies ◽  
Mitigation Measures ◽  
Forest Protection ◽  
Wood Supply ◽  
Long Run ◽  
Biological Insecticide ◽  
Salvage Harvesting

Forest protection (spraying of biological insecticide), salvage harvesting, and strategic re-planning are typical mitigation options to reduce wood supply impacts caused by spruce budworm (Choristoneura fumiferana [Clem.]) defoliation. However, all such measures are expensive and difficult to implement, and decisions about if and to what extent such measures should be applied hinge on the magnitude of benefits and associated costs. We used an integrated forest estate pest-impact planning model to quantify harvest impacts for three plausible outbreak scenarios, and the effect of these typical mitigation strategies for 3.0 million ha in New Brunswick. Cumulative harvest reductions, relative to the no defoliation case, reached 18% and 25% by 2052 under moderate and severe defoliation patterns, respectively. We demonstrate that up to 30% to 50% of these projected reductions could be avoided through foliage protection treatments, depending on the outbreak scenario. Salvage and re-planning mitigated harvest losses by up to 20% in the short term (20 to 25 years), but had little benefit over the long run (40+ years). Even with aggressive implementation of all mitigation measures, significant harvest impacts (10% reduction from 2017 to 2042) were unavoidable, regardless of outbreak scenario.

scholarly journals Validation of Spruce Budworm Outbreak History Developed from Aerial Sketch Mapping of Defoliation in New Brunswick

2008 ◽  
Vol 25 (3) ◽  
pp. 139-145 ◽  
Author(s):  
Sarah L. Taylor ◽  
David A. MacLean
Keyword(s):  
New Brunswick ◽  
Choristoneura Fumiferana ◽  
Abies Balsamea ◽  
Spruce Budworm ◽  
Weather Conditions ◽  
Growth Data ◽  
Growth Reduction ◽  
Increment Core ◽  
Permanent Sample Plots ◽  
Ground Survey

Abstract Aerial sketch mapping (ASM) of annual defoliation provides a means to quantify spruce budworm (Choristoneura fumiferana Clem.) outbreak histories, but accuracy is affected by factors such as navigation and weather conditions. We used ground-based defoliation estimates from 123 permanent sample plots (PSP) in New Brunswick and increment core growth data from a subset of PSPs, to validate ASM estimates of defoliation. From 1985 to 1993, 85% of 332 cases were correctly classified by aerial estimates as nil–light (0–30%) or moderate–severe (31–100%), with the proportion correct varying by measurement year, defoliation severity, and host species. Growth indices generated from 81 visually cross-dated and verified balsam fir (Abies balsamea [L.] Mill.) tree-ring series in 23 PSPs were significantly negatively correlated with aerial-derived cumulative defoliation for 87% of the PSPs, and correlation increased when aerial estimates were combined with ground survey data. We conclude that aerial surveys provide a reasonable estimate of defoliation history to estimate growth reduction.

scholarly journals FUNGOUS DETERIORATION OF BALSAM FIR KILLED BY SPRUCE BUDWORM IN NORTHWESTERN NEW BRUNSWICK

1964 ◽  
Vol 40 (4) ◽  
pp. 482-487 ◽  
Author(s):  
M. A. Stillwell ◽  
D. J. Kelly
Keyword(s):  
New Brunswick ◽  
Tree Mortality ◽  
Choristoneura Fumiferana ◽  
Abies Balsamea ◽  
Spruce Budworm ◽  
Balsam Fir ◽  
Dead Trees ◽  
One Year ◽  
Different Parts ◽  
Heavy Mortality

The rate of fungous deterioration was determined for 292 balsam fir (Abies balsamea (L.) Mill.) killed by the spruce budworm (Choristoneura fumiferana (Clem.) in an area of heavy tree mortality in northern New Brunswick. Trees dead less than one year and up to seven years were examined. Fifty fir trees dead 0 to 2 years in a light mortality area were also examined. Trees in the heavy mortality area deteriorated much more slowly than those examined by other workers in Ontario. Stereum chailletii (Pers.) Fr. and S. sanguinolentum (Alb. & Schw. ex Fr.) Fr. caused most of the incipient and advanced decay in New Brunswick, whereas S. chailletii caused all the incipient decay in trees dead less than one year in Ontario but was replaced after one year by Polyporus abietinus Dicks, ex Fr. which then caused most of the advanced decay. Advanced decay progressed faster in trees in the light mortality area in New Brunswick than in trees in the heavy mortality area. Nineteen species of basidiomycetes were associated with sapwood decay. Comments concerning the position and frequency of fungous occurrence in the different parts of the tree in relation to the number of years since death are made for eight of the more commonly isolated fungi. The introduction of S. chailletii into living trees by woodwasps and the differences observed in the development of P. abietinus in dead trees in the two regions are discussed.

Potential wood supply losses to spruce budworm in New Brunswick estimated using the Spruce Budworm Decision Support System

2002 ◽  
Vol 78 (5) ◽  
pp. 739-750 ◽  
Author(s):  
D A MacLean ◽  
K P Beaton ◽  
K B Porter ◽  
W E MacKinnon ◽  
M G Budd
Keyword(s):  
Decision Support ◽  
Decision Support System ◽  
New Brunswick ◽  
Support System ◽  
Choristoneura Fumiferana ◽  
Abies Balsamea ◽  
Spruce Budworm ◽  
Timber Harvesting ◽  
Management Plan ◽  
Forest Protection

The Spruce Budworm Decision Support System (SBW DSS) was used to estimate potential volume losses to a future spruce budworm (Choristoneura fumiferana (Clem.)) outbreak in New Brunswick. The SBW DSS was implemented separately on each of the ten Crown Timber Licenses, using data from forest industry management plan timber yields and harvest schedules; values were then compiled for all of New Brunswick. Potential volume losses on privately owned forest (industrial freehold and private woodlots) were estimated by matching stand types with those for Crown land. Total potential volume losses of 83 million and 195 million m3 of spruce–fir (Picea spp. – Abies balsamea (L.) Mill.) were predicted for "normal" and "severe" budworm outbreak scenarios, defined based on past outbreaks in New Brunswick and Nova Scotia and assumed to start in 2000. Simulated timber supply losses were 42 million, 40 mil-lion, and 1 million m3 on Crown, freehold, and federal land, respectively, under a normal outbreak scenario, versus 99 million, 92 million, and 3 million m3 under a severe outbreak scenario. On Crown land, 33% of the predicted loss in a severe outbreak occurred in stands scheduled for harvest over the next 30 years, 26% occurred in stands not scheduled for harvest for at least 30 years, and 41% was in the non-timber harvesting landbase (11% in Old Softwood Forest Habitat, 12% in Deer Wintering Areas, 14% in riparian buffers, and 3% in inaccessible areas). Harvest levels 11–20 years in the future were very sensitive to reduction in yields caused by defoliation. Under a severe outbreak scenario, if 40% of the landbase was not protected for 2, 5, or 8 years to limit defoliation (simulating spraying the insecticide Bacillus thuringiensis, B.t.), 2007–2011 harvest level reductions of 4.0, 6.0, and 8.4 million m3 , respectively, would be necessary. We conclude that the only way that planned harvest levels for New Brunswick can be maintained, under a future spruce budworm outbreak, is with effective targeted use of insecticides for forest protection. Key words: defoliation, growth reduction, mortality, protection planning

scholarly journals Protection Strategy against Spruce Budworm

Forests ◽  
2019 ◽  
Vol 10 (12) ◽  
pp. 1137
Author(s):  
David A. MacLean
Keyword(s):  
Early Intervention ◽  
New Brunswick ◽  
Environmental Effects ◽  
Economic Impacts ◽  
Intervention Strategy ◽  
Spruce Budworm ◽  
Special Issue ◽  
Protection Strategy ◽  
Forest Insects ◽  
Considerable Success

Spruce budworm is one of the most significant forest insects worldwide, in terms of outbreak extent, severity, and economic impacts. As a defoliator, spruce budworm larvae are susceptible to insecticide protection, and improvements in efficacy and reductions in non-target environmental effects have made such protection attractive. In this Special Issue, 12 papers describe the advances in spruce budworm protection, most notably an ‘early intervention strategy’ approach that after six years of trials in New Brunswick, Canada, shows considerable success to date in reducing budworm outbreak occurrence and severity.

Derivation of Pheromone-Based Larval Thresholds in Spruce Budworm Accounting for Distance to Defoliated Forest Stands

2021 ◽  
Author(s):  
Marc Rhainds ◽  
Ian DeMerchant ◽  
Pierre Therrien
Keyword(s):  
Boreal Forests ◽  
Large Scale ◽  
Choristoneura Fumiferana ◽  
Intervention Strategy ◽  
Spruce Budworm ◽  
Interactive Effects ◽  
The Novel ◽  
Forest Stands ◽  
General Guideline ◽  
Number Of Males

Abstract Spruce budworm, Choristoneura fumiferana Clem. (Lepidoptera: Tortricidae), is the most severe defoliator of Pinaceae in Nearctic boreal forests. Three tools widely used to guide large-scale management decisions (year-to-year defoliation maps; density of overwintering second instars [L2]; number of males at pheromone traps) were integrated to derive pheromone-based thresholds corresponding to specific intergenerational transitions in larval densities (L2i → L2i+1), taking into account the novel finding that threshold estimates decline with distance to defoliated forest stands (DIST). Estimates of thresholds were highly variable between years, both numerically and in terms of interactive effects of L2i and DIST, which limit their heuristic value. In the context of early intervention strategy (L2i+1 &gt; 6.5 individuals per branch), however, thresholds fluctuated within relatively narrow intervals across wide ranges of L2i and DIST, and values of 40–200 males per trap may thus be used as general guideline.

Weather and Outbreaks of the Spruce Budworm in the Province of Quebec from 1939 to 1956

1961 ◽  
Vol 93 (2) ◽  
pp. 118-123 ◽  
Author(s):  
J. G. Pilon ◽  
J. R. Blais
Keyword(s):  
Choristoneura Fumiferana ◽  
Abies Balsamea ◽  
Spruce Budworm ◽  
Balsam Fir ◽  
The Past ◽  
Forest Regions ◽  
Tree Component ◽  
Gaspe Peninsula ◽  
Gaspé Peninsula

Nearly all forest regions in the Province of Quebec where balsam fir (Abies balsamea (L.) Mill.) is an important tree component have been subjected to severe defoliation by the spruce budworm, Choristoneura fumiferana (Clem.), during the past 20 years. These outbreaks have followed an easterly direction beginning near the Ontario-Quebec border in 1939 and ending in the Gaspé Peninsula in 1958.

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