ThibaultBeginBelanger1995

Référence

Thibault, D., Bégin, J., Belanger, L. (1995) Relationships between growth-rate indicators of the balsam fir during an initial outbreak and its vulnerability to the spruce budworm. Canadian Journal of Forest Research, 25(8):1292-1302.

Résumé

Integrated pest management strategies for the spruce budworm (Choristoneura fumiferana (Clem.)) give high priority to preventive silvicultural treatments that increase the vigour of balsam fir stands to decrease their vulnerability. The aim of this study was to determine to which extent the survival probability of individual balsam firs (Abies balsamea L.), during the last budworm outbreak (1974-1986), was related to some growth rate indicators evaluated at the Béginning of the outbreak. The study was carried out in two permanent study sites, established initially to follow the impact of precommercial thinnings on growth and yield in young boreal fir stands in eastern Quebec: the area of Lake Matapedia, thinned in 1968 and protected by chemical insecticides, and the area of Lake Huit-Milles, thinned in 1960 and not protected. Discriminant logistic models, based on tree diameters in 1976 and diameter growth rates between 1968 and 1976, were used to determine if it was possible to discriminate the state of the trees (living or dead) at the end of the outbreak. Using Dagnelie's transformation of the logistic model, we produced linear probability models that were called survival thresholds. In the protected study area (Lake Matapedia), the models correctly predicted the state of 81% of the individual trees in 1989 for the validation sample. In the unprotected stands (Lake Huit-Milles), we observed a higher position of the survival thresholds following higher defoliation levels. The relationship between tree growth indicators and tree vulnerability is stronger when defoliation levels are low to moderate, but is clearly weaker when defoliation is severe. At high levels of defoliation and without insecticide spraying programs, even vigourous trees become vulnerable.

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@ARTICLE { ThibaultBeginBelanger1995,
    AUTHOR = { Thibault, D. and Bégin, J. and Belanger, L. },
    TITLE = { Relationships between growth-rate indicators of the balsam fir during an initial outbreak and its vulnerability to the spruce budworm },
    JOURNAL = { Canadian Journal of Forest Research },
    YEAR = { 1995 },
    VOLUME = { 25 },
    PAGES = { 1292-1302 },
    NUMBER = { 8 },
    ABSTRACT = { Integrated pest management strategies for the spruce budworm (Choristoneura fumiferana (Clem.)) give high priority to preventive silvicultural treatments that increase the vigour of balsam fir stands to decrease their vulnerability. The aim of this study was to determine to which extent the survival probability of individual balsam firs (Abies balsamea L.), during the last budworm outbreak (1974-1986), was related to some growth rate indicators evaluated at the Béginning of the outbreak. The study was carried out in two permanent study sites, established initially to follow the impact of precommercial thinnings on growth and yield in young boreal fir stands in eastern Quebec: the area of Lake Matapedia, thinned in 1968 and protected by chemical insecticides, and the area of Lake Huit-Milles, thinned in 1960 and not protected. Discriminant logistic models, based on tree diameters in 1976 and diameter growth rates between 1968 and 1976, were used to determine if it was possible to discriminate the state of the trees (living or dead) at the end of the outbreak. Using Dagnelie's transformation of the logistic model, we produced linear probability models that were called survival thresholds. In the protected study area (Lake Matapedia), the models correctly predicted the state of 81% of the individual trees in 1989 for the validation sample. In the unprotected stands (Lake Huit-Milles), we observed a higher position of the survival thresholds following higher defoliation levels. The relationship between tree growth indicators and tree vulnerability is stronger when defoliation levels are low to moderate, but is clearly weaker when defoliation is severe. At high levels of defoliation and without insecticide spraying programs, even vigourous trees become vulnerable. },
    KEYWORDS = { STANDS; MORTALITY; MODEL },
    OWNER = { brugerolles },
    TIMESTAMP = { 2007.12.05 },
}

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