Dendrochronological reconstruction of forest tent caterpillar outbreaks in time and space, western Manitoba, Canada

Abstract

A tree-ring reconstruction of forest tent caterpillar (Malacosoma disstria Hubner) outbreaks was conducted in the Duck Mountain Provincial Forest. Trembling aspen (Populus tremuloides Michx.), balsam poplar (Populus balsamifera L.), and paper birch (Betula papyrifera Marsh.) tree-ring chronologies were used to identify periods of outbreaks from approximately 1800 to 2002. The impacts of the major forest tent caterpillar outbreaks of the 20th century were compared among four stand types and two age classes. The presence of white rings and growth suppression were used to identify three important outbreak periods, 1939-1948, 1961-1965, and 1982-1985, with another large-scale outbreak suspected during the 1870s. A roughly 20-year interval was observed between major outbreaks. Few differences were found between stand types, except during the 1960s, when mixed stands with jack pine (Pinus banksiana Lamb.) registered more growth suppression and white rings. In general, the outbreak signal in the younger sites was variable. The importance of utilizing white rings and growth suppression data together is discussed. The major outbreaks of the 20th century generally started in the north of the Duck Mountain Provincial Forest. The technique was successful at identifying forest tent caterpillar outbreaks during the 20th and late 19th centuries, when no historical surveys were available. Résumé: Une reconstitution dendrochronologique des épidémies de livrée des forêts (Malacosoma disstria Hubner) a été réalisée à la forêt provinciale de Duck Mountain. Des chronologies du peuplier faux-tremble (Populus tremuloides Michx.), du peuplier baumier (Populus balsamifera L.) et du bouleau à papier (Betula papyrifera Marsh.) ont été utilisées pour identifier les périodes d'épidémie de 1800 à 2002 environ. L'impact des épidémies majeures de livrée des forêts au 20 e siècle a été comparé dans quatre types de peuplement et deux classes d'âge. La présence de cernes traumatiques pâles et la suppression de la croissance ont été utilisées pour identifier trois périodes d'épidémie importante, soit 1939-1948, 1961-1965 et 1982-1985, ainsi qu'une autre épidémie de grande envergure qui, croit-on, serait survenue durant les années 1870. Un intervalle d'à peu près 20 ans a été observé entre les épidémies majeures. Peu de différences ont été observées entre les types de peuplement, excepté durant les années 1960, alors qu'une plus forte suppression de la croissance et plus de cernes traumatiques pâles ont été observés dans les peuplements mélangés avec du pin gris (Pinus banksiana Lamb.). En général, le signal des épidémies était variable dans les stations plus jeunes. L'importance d'utiliser conjointement les cernes traumatiques pâles et la suppression de la croissance est discutée. Les épidémies majeures au 20 e siècle ont général-ement débuté dans le nord de la forêt provinciale de Duck Mountain. La technique a pu identifier des épidémies de livrée des forêts survenues au cours du 20 e siècle et à la fin du 19 e siècle alors qu'aucun relevé passé ...

Boreal mixedwood stand dynamics: ecological processes underlying multiple pathways

“…Outbreaks of this insect cause substantial and sustained reduction in leaf area and live crown volume in aspen stands and slow the radial growth of trees (Cooke and Roland 2007, Sutton and Tardif 2007, Moulinier et al 2011. At the landscape scale, forest tent caterpillar outbreaks show strong periodicity with peak outbreaks being decadal and usually lasting less than five years; however, at a more local scale outbreaks can be more frequent and/or last for as long as a decade (Cooke and Roland 2007).…”

“…Forest tent caterpillar is present throughout the boreal mixedwoods, but is a more influential Table 1. Summary of key differences between the eastern and western portions of the boreal mixedwood region in Canada (Hare and Thomas 1979, Larsen 1980, Fulton 1989, Lenihan 1993 disturbance agent in the western boreal, because trembling aspen is one of the most common tree species (Hogg and Schwarz 1999, Cooke and Roland 2007, Sutton and Tardif 2007. Aspen in western Canada is also impacted by severe drought conditions that reduce growth and cause dieback (Hogg et al 2002, Brandt et al 2003, Frey et al 2004, Hogg et al 2008.…”

Drought and surface‐level solar radiation predict the severity of outbreaks of a widespread defoliating insect

“…), in our study region of southcentral Canada (Sims et al 1990, Sutton andTardif 2007). ), in our study region of southcentral Canada (Sims et al 1990, Sutton andTardif 2007).…”

“…Inspection of annual growth rings has been used for reconstructing the outbreak histories of several different forestdefoliating insects, incorporating time spans of centuries and even millennia (Swetnam and Lynch 1989, Esper et al 2007, Sutton and Tardif 2007, Young et al 2014, Axelson et al 2015. Perhaps the most compelling approach for assessing anthropogenically driven changes to defoliator cycles is through evaluation of long-term time series derived from radial growth chronologies from woody plant host species.…”

Preliminary hazard rating for forest tent caterpillar in British Columbia

“…disstria was first recorded causing noticeable defoliation on fruit and ornamental trees in British Columbia as early as 1907 or 1908 (Bush 1911), but annual recording of defoliation by this insect in BC was not started until 1944. Tree-ring evidence from Manitoba (Sutton and Tardif 2007) and Quebec (Huang et al 2008) suggests that FTC outbreaks occurred in Canada, and by inference in BC, at least 100 to 150 years before these early records. Since 1944, six outbreaks of M. disstria have been recorded in BC.…”