Cartographie du risque de retrouver de la mortalité dans les forêts de sapin baumier attaquées par la tordeuse des bourgeons de l'épinette

Hardy, Yvan; Dorais, Louis G.

doi:10.1139/x76-036

Cited by 6 publications

(7 citation statements)

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“…Fuentealba et al. () suggested that RPC could be used to better estimate the effects of damage by SBW than the measures of defoliation used in short‐term studies because RPC is less sensitive to fluctuations in SBW population (Hardy and Dorais ). We did not observe a direct relationship between AD and NEP; however, there was a clear inverse relationship between AD DS1 and NEP DS1 for all forest types early (Table ).…”

Section: Discussionmentioning

confidence: 99%

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Aerial spraying of bacterial insecticides to control spruce budworm defoliation leads to reduced carbon losses

et al. 2020

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Spruce budworm (SBW) outbreaks are a major natural disturbance in boreal forests of eastern North America. During large-scale infestations, aerial spraying of bacterial insecticides is used to suppress local high-density SBW populations. While the primary goal of spraying is the protection of wood volume for later harvest, it should also maintain carbon stored in trees. This study provides the first quantitative analysis of the efficacy of aerial spraying against SBW on carbon dynamics in balsam fir, spruce, and mixed fir-spruce forests. In this study, we used the TRIPLEX-Insect model to simulate carbon dynamics with and without spray applications in 14 sites of the boreal forest located in various regions of Qu ebec. We found that the efficacy of aerial spraying on reducing annual defoliation was greater in the early stage (<5 yr since the outbreak began) of the outbreak than in later (5-10 yr since the outbreak began) stage. Our results showed that more net ecosystem productivity is maintained in balsam fir (the most vulnerable species) than in either spruce or mixed fir-spruce forests following spraying. Also, average losses in aboveground biomass due to the SBW following spraying occurred more slowly than without spraying in balsam fir forests. Our findings suggest that aerial spraying could be used to maintain carbon in conifer forests during SBW disturbances, but that the efficacy of spray programs is affected by host species and stage of the SBW outbreak.

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Section: Discussionmentioning

confidence: 99%

“…While defoliation thresholds used to determine when Btk should be applied vary provincially, spraying often occurs only after substantial defoliation is detected. For example, in Québec, aerial spraying is applied only after one year of moderate‐to‐severe SBW defoliation (Hardy and Dorais , Bauce et al. , Fuentealba et al.…”

Section: Introductionmentioning

confidence: 99%

Aerial spraying of bacterial insecticides to control spruce budworm defoliation leads to reduced carbon losses

et al. 2020

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“…The new protection policy aimed at protecting at least 50% of current year foliage to keep trees alive. This foliage protection target was based on the study of Hardy and Dorais (1976), which used the estimated contribution made by the various ages of foliage to the total photosynthetic capacity of balsam r reported by Clark (1961) to evaluate the capacity of balsam r to recover after spruce budworm defoliation. Their results suggest low balsam r mortality when 38 to 51% of its photosynthetic capacity is maintained by the end of the outbreak.…”

Section: Introductionmentioning

confidence: 99%

“…According to Dorais et al (1995), 80% of treated areas were adequately protected in terms of foliage protection 10 out of 14 years between 1974 and 1987 which demonstrate that the spraying operations conducted in Quebec met the protection goal. Despite the good results in terms of foliage protection and the link between the aforementioned variable and tree mortality (Hardy and Dorais 1976), there exists little information on the long-term e cacy of aerial applications of insecticides in reducing budworm-related tree mortality. For example, an early study reported that sprayed stands with DDT exhibited 11% mortality rate (2% of the basal area) whereas tree mortality reached 44% (44% of basal area) in unprotected stands (Batzer 1973).…”

Section: Introductionmentioning

confidence: 99%

Efficacy of Insecticide Aerial Spraying Programs to Reduce Tree Mortality During a Spruce Budworm Outbreak (1967‒1992) in the Quebec Province.

Fuentealba

Dupont

Quezada-García

et al. 2021

Preprint

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Spruce budworm (Choristoneura fumiferana) is the most important pest of conifer forests in Eastern North America. The main approach to protect Quebec forests against this defoliator is aerial spraying of insecticides. Despite the crucial role of aerial spraying of insecticides in the global forest protection strategy, little is known about its real impact on tree mortality reduction or the stand characteristics that may affect its long-term efficacy. We evaluate the efficacy of the protection program implemented between 1967 and 1992 in reducing tree mortality during the previous outbreak in Quebec and how its efficacy is affected by stand characteristics such as drainage quality and stand age. We established 422 plots in Eastern Quebec based on the following parameters: insecticide application (0-13 years), stand composition, drainage quality, and stand age at the beginning of the previous outbreak. Our results show that unprotected plots exhibited in average between 18 and 32.6% higher mortality than protected plots. Insecticide efficacy was affected by drainage quality. For example, protected plots established on sites with bad drainage quality exhibited 49% less balsam fir mortality than unprotected plots. Furthermore, immature and mature protected stands exhibited a similar reduction in balsam fir mortality (32.2 and 32.1% less mortality respectively) compare to unprotected stands. Our results may be useful for decision-makers not only to decide where and when apply insecticides during a spruce budworm outbreak but also, they may help to determine the pertinence of continuous protection during longer than usual outbreaks depending on protection goal.

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“…), un insecte defollateur du sapin baumier, Abies balsamea Mill., et des epinettes blanche et rouge, Plcea glauca Voss et P. rubens Sarg., est consideree par certains comme I'ennemi numero un au niveau economique des for& resineuses du nord-est de I'Amerique (Miller, 1975). Des epidemies repetees, (Blais, 1965;Swaine et Craighead, 1924), et une tendance de ces dernieres a revenir intervalles plus courts (Blais, 1974) ont ete a I'origine de nombreuses etudes sur la biologie de I'insecte, (Mitchell et Seabrook, 1970), la susceptibilite des forBts (Blais, 1968;Hardy et Dorais, 1976;Morris et Bishop, 1951) et I'epidemiologie (Blackman, 1919;Blais 1964). Toutefois, rares sont les etudes d'impact sur le milieu forestier (Baskerville et MacLean, 1979;Batzer, 1973;Bla~s 1981;McLlntock, 1955), malgre de nombreux estlmes lmprec~s (Baskerville, 1960, Blals, 1958Morris, 1946).…”

Section: Introductionunclassified

Mortalité du sapin baumier défolié par la tordeuse des bourgeons de l'épinette dans la région de la Gatineau au Québec

Beaulieu¹,

Hardy²

1982

The Forestry Chronicle

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This paper presents a method of analysis which differentiates between spruce budworm caused mortality and regular mortality on balsam fir in the Gatineau region in Quebec. A first attempt was made using multiple linear regression and a uniform random number generator. In order to overcome the bias inherent to the least squares method when dealing with a binary (0,1) dependent variable, a profit analysis was also conducted. In this case, the parameters and their variance were estimated using likehood method. These two approaches proved to be equivalent when percent budworm caused mortality was compared within the 1958 to 1979 period covered by the data at hand, while the outbreak lasted from 1968 to 1975.In 1979, approximately 55% of the stems had been killed by the budworm, accounting for 53% of the volume. Maple-yellow birch associations were more affected than fir associations although no significant difference was found. Fir mortality was delayed by aerial spraying of insecticides but this advantage disappeared as soon as the spray operations came to an end.

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Cartographie du risque de retrouver de la mortalité dans les forêts de sapin baumier attaquées par la tordeuse des bourgeons de l'épinette

Cited by 6 publications

References 0 publications

Aerial spraying of bacterial insecticides to control spruce budworm defoliation leads to reduced carbon losses

Aerial spraying of bacterial insecticides to control spruce budworm defoliation leads to reduced carbon losses

Efficacy of Insecticide Aerial Spraying Programs to Reduce Tree Mortality During a Spruce Budworm Outbreak (1967‒1992) in the Quebec Province.

Mortalité du sapin baumier défolié par la tordeuse des bourgeons de l'épinette dans la région de la Gatineau au Québec

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