Interactions among fire, insects and pathogens in coniferous forests of the interior western United States and Canada

Abstract

1 Natural and recurring disturbances caused by fire, native forest insects and pathogens have interacted for millennia to create and maintain forests dominated by seral or pioneering species of conifers in the interior regions of the western United States and Canada. 2 Changes in fire suppression and other factors in the last century have altered the species composition and increased the density of trees in many western forests, leading to concomitant changes in how these three disturbance agents interact. 3 Two-and three-way interactions are reviewed that involve fire, insects and pathogens in these forests, including fire-induced pathogen infection and insect attack, the effects of tree mortality from insects and diseases on fuel accumulation, and efforts to model these interactions. 4 The emerging concern is highlighted regarding how the amount and distribution of bark beetle-caused tree mortality will be affected by large-scale restoration of these fire-adapted forest ecosystems via prescribed fire. 5 The effects of fire on soil insects and pathogens, and on biodiversity of grounddwelling arthropods, are examined. 6 The effects of fire suppression on forest susceptibility to insects and pathogens, are discussed, as is the use of prescribed fire to control forest pests.

Effect of prescribed fire on soil properties and soil erosion in a Mediterranean mountain area

“…There are many reasons to apply prescribed fire in forest management as, for instance, it reduces hazardous fuels and breaks up fuel continuity (Fernandes and Botelho, 2004;Fernandes and Loureiro, 2010), it prepares sites for seeding or planting of forest species, and controls the competing vegetation (Brooks and Lusk, 2009), it improves habitat and creates diversity needed by wildlife (Wasserman, 2015), it controls insects and diseases (Parker et al, 2006), it improves pasture quality for cattle (Fonseca et al, 2011), it improves access into forest stands, and it contributes to preserve fire-dependent plant species, particularly important in Mediterranean environments (Pausas and Keeley, 2009). Prescribed fire in shrublands applied to protect forests stands is a relatively common practice in Montesinho Natural Park (PNM), Northeast Portugal (IPB/ ICN, 2007;Fonseca et al, 2011).…”

Untitled

“…Although bark beetle attacks and fire are common disturbances in forest ecosystems, variability in initial conditions, the temporal phase, severity of bark beetle-caused mortality, and the fire weather can lead to different conclusions about the interaction of these two disturbances (Parker et al 2006). Our design that controlled for initial conditions and incorporated a full-factorial range of three factors thought to control fire severity following bark beetle mortality provided insights into disturbance interactions and aids in explaining seemingly contrasting results among previous studies.…”

An economic comparison of risk handling measures against Hylobius abietis and Heterobasidion annosum in the Landes de Gascogne Forest

“…For example, Parker et al (2006) analyze the interactions among fire, insects, and pathogens in coniferous forests in the USA and Canada. Focusing on the forest insurance against natural events, Brunette et al (2015) deepen the analysis of the link between several randomly occurring natural hazards (storm, insects, and fire).…”