Sequential patterns of colonization of coarse woody debris by Ips pini (Say) (Coleoptera: Scolytidae) following a major ice storm in Ontario

Abstract

1 It is widely known that many bark and wood-boring beetle species use nonresistant coarse woody debris (CWD) created by disturbances; however, the ability of these secondary species to cause mortality in healthy trees following a build-up of their populations remains unclear. We characterized the pattern of colonization by Ips pini (Say) following a major ice storm that created large amounts of CWD varying in resistance to colonization (i.e. ranging from snapped tops with no resistance to heavily damaged trees with intact root systems). A major question was how the beetles responded to the different types of storm-damaged material and whether healthy undamaged trees were colonized and killed following increases in beetle populations. 2 Six red pine, Pinus resinosa Ait., plantations in eastern Ontario were monitored from 1998 to 2001 inclusive: three with high storm damage (approximately 120 m 3 /ha CWD) and three with minimal damage (approximately 20 m 3 /ha CWD). Transects (200 Â 2 m) were sampled yearly in each plantation to assess the type and amount of damaged pine brood material colonized by the pine engraver beetle, I. pini. 3 Beetles preferentially infested the most nonresistant material available each year (i.e. all snapped tops in year 1, all standing snags, up-rooted trees and many bent trees by year 2, but still less than 50% of trees blown over but with intact root systems by year 3). By years 3 and 4, the majority (approximately 75%) of severely damaged trees (with > 50% crown loss) died prior to beetle colonization. 4 The size of the beetle population tracked the abundance of available woody material from year-to-year within a plantation; populations were very large in the first 2 years, and declined significantly in the last 2 years. 5 Healthy standing red pines were apparently resistant to colonization by the beetles, despite the significant build-up in their populations. Hence, the results of the present study suggest that native bark beetle populations will not cause further tree mortality following such a disturbance in this region.

Application of Semiochemicals to Assess the Biodiversity of Subcortical Insects following an Ecosystem Disturbance in a Sub-boreal Forest

“…Possible reasons for the decline of early-successional subcortical insect flight activity with time are: increasing populations of insect (Ryall 2003;Ryall et al 2006) and avian (Baldwin 1968;Fayt et al 2005) natural enemies (Ryall and Smith 2001); greater inter-and intra-specific competition (Robins and Reid 1997); lower availability and quality of CWD as habitat on the disturbed landscape (Wallace 1953;Wickman 1965;Jacobs 2004); and/or rapid salvaging of other downed material on the landscape (USDA Forest Service 1962. Similar results were reported for the activity of I. pini in ice-damaged P. resinosa stands in Ontario where beetle activity declined markedly 2-4 years after the storm (Ryall et al 2006), and for the activity of Dendroctonus brevicomis LeConte in wind-damaged stands in California where beetle activity declined 2 years after the storm (Miller 1928). Populations of Ips typographus (L.) and other subcortical beetles peaked 2 years after a wind storm (Vivian) in Switzerland (Wermelinger et al 1999) and after another wind storm (Lothar) in 1999 in France (Nageleisen 2001).…”

Coarse woody debris decay rates for seven indigenous tree species in the central North Island of New Zealand

“…Large quantities of woody debris are deposited periodically on the forest floor during severe storms (see for example Keller et al, 2004;Ryall et al, 2006;Woodall and Nagel, 2007). The effect of severe storms on forests was noted in an investigation initiated following cyclone Bernie, in April 1982, when it was concluded that they have had a major influence on stand structure and pattern in indigenous forests throughout New Zealand (Shaw, 1983).…”

Enhancing Stand Structure through Snag Creation in Northeastern U.S. Forests: Using Ethanol Injections and Bark Beetle Pheromones to Artificially Stress Red Maple and White Pine

“…Trees were baited with ipsdienol and lanierone, both aggregation pheromones used by I. pini during host colonization [49]. This beetle has been reported to occasionally kill living trees [50][51][52] but generally behaves as a secondary species in eastern North American forests [53,54]. Mass attack by Ips pini and inoculation of its associated fungi into trees was likely responsible for ultimately killing trees.…”