The influence of shelter and the hypothetical effect of fire severity on the postfire establishment of conifers from seed

Abstract

Surface-charred organic matter is a common but unfavourable postfire seedbed in eastern Canada. Slatted screens providing 0, 25, 50, and 75% cover were used to shelter 1-m2 charred plots from direct sunlight. Plots were sown with four conifer species. Jack pine (Pinnsbanksiana Lamb.) established abundantly on all plots and dominated on unsheltered areas. As shelter increased, eastern white pine (Pinusstrobus L.), and eventually balsam fir (Abiesbalsamea (L.) Mill.) and black spruce (Piceamariana (Mill.) B.S.P.) increased in number. Thus, the size and composition of the seedling community depended upon the amount of shelter given. To test whether postfire herbaceous and shrub vegetation could have a similar effect, seeds were sown on pairs of charred 1-m2 plots. Vegetation was removed weekly from one plot of each pair. Removal of vegetation decreased the establishment of balsam fir and black spruce but not red pine (Pinusresinosa Ait.). It was concluded that, during the first growing season, changes in vegetation cover produce changes in establishment similar to those found using slatted screens. Increasing fire severity (organic matter consumption) may reduce the postfire vegetation cover. A hypothetical model is presented, linking the establishment of the above five species to fire severity.

Spatial and temporal variability of forest floor duff characteristics in long-unburnedPinus palustrisforests

“…Spatial patterns of duff consumption during fires are important for postfire seedling recruitment and the ultimate regeneration of herbaceous plants and subsequent generations of the overstory (Flinn and Wein 1977;Thomas and Wein 1985;Kemball et al 2006). Duff consumption may be critical for groundcover restoration in long-unburned longleaf pine forests where grass and forb establishment is desired and a more frequent fire regime is a goal for ecological restoration (Van Lear et al 2005;Hiers et al 2007).…”

Does post-fire plant regeneration mode affect the germination response to fire-related cues?

“…Inhibition of germination by ash has been demonstrated in a range of Wre-prone northern hemisphere plant species (Thomas and Wein 1985;GonzalesRabanal et al 1989;Ne'eman et al 1993;Gonzalez-Rabanal and Casal 1995;Eshel et al 2000). Only two published studies report the eVects of ash on germination in the Australian Xora.…”

Effects of fire and mechanical wounding on Pinus resinosa resin defenses, beetle attacks, and pathogens

“…In addition, the natural history of P. resinosa is closely associated with fire, which can cause wounding and mortality to mature trees and contribute to the establishment of seedlings (Thomas and Wein, 1985;Bergeron and Brisson, 1990;Clark, 1990). Understanding relationships with fire is of increasing relevance to modern forestry practices, where prescribed fire is becoming a common tool (Cain et al, 1998;Mutch and Parsons, 1998;Elliott et al, 1999).…”