A comparison of mature with recently clear-cut and scarified lodgepole pine forests in the Lower Foothills of Alberta

Abstract

Mature, even-aged lodgepole pine (Pinuscontorta Dougl. var latifolia Engelm.) forests on upland sites with Orthic Gray Luvisols in the Lower Foothills of Alberta have been clear-cut for pulpwood and scarified by bulldozer since 1958. Undisturbed stands had weak shrub strata, well developed herb – dwarf shrub strata, and continuous feather moss strata.In 25 clear-cut stands 6–12 years old, the average cover of vascular plants was 54% and did not change significantly during the sampled age interval. Cover of tree 'regeneration' (immature size classes) was 5%, increasing slowly, and codominated by lodgepole pine and aspen (Populustremuloides Michx.). Shrub cover was also 5% and dominated by prickly rose (Rosaacicularis Lindl.). Herb – dwarf shrub cover was 44% and dominated by nine species of the mature forest. Bryoid cover was 13 %.The density of young trees stabilized within 6 years after clear-cutting, and the above-ground biomass of both pine and aspen increased rapidly during the sampled age interval.An ordination of the clear-cut stands showed that the distribution and abundance of several important plant species were well correlated with soil moisture on two gravimetric sampling dates in summer.A comparison of dominance–diversity curves and indices for mature and clear-cut stands revealed that the clear-cut community was richer in vascular species (100 cf. 57) and had a more even distribution of cover among species.The early stages of secondary succession after clear-cutting and scarification of lodgepole pine forest are discussed.

Sex-ratio variation and the function of staminodes inAralia nudicaulis1This article is part of a Special Issue entitled “Pollination biology research in Canada: Perspectives on a mutualism at different scales”.

“…Our data and the predictions made by Barrett and Helenurm (1981) run counter to observations made for another clonal dioecious herb, Mercurialis perennis L. Both species are found almost exclusively under intact forest understories, but A. nudicaulis can also be found in disturbed and logged forests (e.g., regenerating clear-cut forests; Corns andLa Roi 1976, cited in Flanagan andBain 1988), whereas M. perennis is an old-growth indicator species that is most commonly found in undisturbed forests (Kenderes and Standovár 2003;Vandepitte et al 2009a). As in other studies of A. nudicaulis, populations of M. perennis tend to be male biased (Vandepitte et al 2009b and references therein).…”

Effects of soil compaction and chipped aspen residue on aspen regeneration and soil nutrients

“…the tree canopy were observed previously in the vicinity of the study area (Corns and La Roi 1976). Disturbance to these plots was minimal but some damage to forb roots and rhizomes from cut aspen boles may have occurred during logging, though feller-bunchers did not enter the plots.…”

Pinus contorta understory vegetation dynamics following clearcutting in west-central Alberta, Canada

“…For example, Corns and La Roi (1976) and Sachro (2003) reported similar increases in graminoid (Leymus innovatushairy wild rye and Calamagrostis canadensis-marsh reedgrass) and forb (e.g., Chamerion angustifoliumfireweed) cover, and a lesser cover of bryophytes on scarified boreal clearcuts and burnt subalpine sites, respectively, relative to unmanaged stands. Bentz (1981), however, reported no difference in the abundance of major growth-forms within two 10-year-old subalpine burn sites relative to mature stands, except decreased graminoid cover at one site.…”