THE RISE AND FALL OF THE SILVICULTURAL HYPOTHESIS IN SPRUCE BUDWORM (CHORISTONEURA-FUMIFERANA) MANAGEMENT IN EASTERN CANADA

The spruce budworm (Choristoneura fumiferana) is a major insect defoli ator of softwood species in northeastern North America. Its commercial importance stems from periodic epidemics during which it damages exte nsively the spruce and fir on which the pulp and paper industry depend s. From around 1920, numerous entomologists and foresters have suggest ed that the damage caused by budworm was due largely to the disruption of natural ecosystems by forestry practices, and could therefore be s ignificantly reduced through appropriate forest management and silvicu ltural measures. However, this 'silvicultural hypothesis' was never im plemented in any significant way by either government or industry. In later years, the hypothesis has been widely rejected on the grounds th at it is based on fallacious assumptions about budworm-forest dynamics . In this paper, the arguments offered on both sides of the debate are assessed and the role of underlying assumptions clarified. It is conc luded that, because these assumptions are relatively impervious to fac tual information, the debate may not be resolvable by reference to add itional scientific information.