Windthrows and Dead-standing Trees as Bark Beetle Breeding Material at Forest-clearcut Edge

Abstract

The spatial distribution of windthrows and dead-standing trees as well as the occurrence of two bark beetle species, Ips typographus and Tomicus piniperda, were studied at forest-clearcut edges in southern Finland. More than 80% of the recorded dead trees were situated within the first 15 m from the clearcut border. The number of dead-standing spruces attacked by I. typographus did not depend on the amount of windthrows at the same site. According to logistic regression analysis, the distance from a clearcut border had a negative effect on the likelihood of I. typographus being present in the windthrows. The results indicate that windthrows do not necessarily increase bark beetle-induced tree mortality under endemic wind conditions. The accumulation of dead trees at forest-clearcut edges may support the diversity of saproxylic species, but may also maintain populations of harmful bark beetles under non-epidemic conditions.

Dead wood creation and restoration burning: Implications for bark beetles and beetle induced tree deaths

“…The treatments, DWR level or burning, or the other predictors had no significant effect on tree deaths. Similar results have been obtained when using not more than five cut spruces (Hedgren et al, 2003) or when using wind-felled trees (Peltonen, 1999) on clear-cut forest edges. In both studies the number of dead standing spruces attacked by I. typographus did not depend on the amount of cut trees or windthrows at the same site.…”

“…typographus breeds commonly in wind-felled trees, large diameter logging waste, and sometimes also in solitary living trees, which they may kill on the edges of clear-cut areas (Peltonen, 1999;Hedgren et al, 2003). For successful breeding in living trees, a high number of colonizing beetles is needed to overcome the defensive systems of the trees (e.g.…”

Does landscape composition alter the spatiotemporal distribution of the pine processionary moth in a pine plantation forest?

“…Habitat is neither rare nor fragmented with regard to PPM dispersion ability, and this raises the question of whether or not landscape affects PPM spatial dynamics (Turner et al 2001). PPM colonies may also display local spatial variability due to edge effects, as has been reported for other forest insects (e.g., bark beetles; see Peltonen 1999). Edge effects may be related to host finding by female moths or other factors and are poorly documented in the literature.…”

The effects of windthrow on forest insect communities: a literature review

“…What we really lack are data about bark beetle and predator dynamics after windthrow in unmanaged stands. Peltonen (1999) showed that the number of dead standing spruces attacked by I. typographus did not depend on the number of windthrow events at the same site. Under endemic wind conditions, i.e.…”

“…Pityogenes chalcographus L. and I. typographus L. attack windthrown spruces in gaps more frequently than they attack trees along edges, which in turn are preferred over trees in closed stands (G€ othlin et al, 2000). Accordingly the likelihood of I. typographus L. being present in windthrow sites inside stands increases towards stand edges facing clear-cuts (Peltonen, 1999). Attack rates (on both windthrown and standing trees) by a bark beetle community dominated by I. typographus is highest in areas Krauss and Funke (1999) -Protoura and Collembola - Spelda et al (1998) -Soil saprophages - Bellmann (1998) -Flower and shrub insects Gutowski and Kubisz (1995) Poland ( with low levels of canopy closure (Jakus, 1995;Jakus, 1998;Schr€ oter et al, 1998b).…”