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Understory plant communities play critical ecological roles in forest ecosystems. Both above- and below-ground ecosystem properties and processes influence these communities but relatively little is known about such effects at fine (i.e., one to several meters within-stand) scales, particularly for forests in which the canopy is dominated by a single species. An improved understanding of these effects is critical for understanding how understory biodiversity is regulated in such forests and for anticipating impacts of changing disturbance regimes. Our primary objective was to examine the patterns of fine-scale variation in understory plant communities and their relationships to above- and below-ground resource and environmental heterogeneity within mature lodgepole pine forests. We assessed composition and diversity of understory vegetation in relation to heterogeneity of both the above-ground (canopy tree density, canopy and tall shrub basal area and cover, downed wood biomass, litter cover) and below-ground (soil nutrient availability, decomposition, forest floor thickness, pH, and phospholipid fatty acids (PLFAs) and multiple carbon-source substrate-induced respiration (MSIR) of the forest floor microbial community) environment. There was notable variation in fine-scale plant community composition; cluster and indicator species analyses of the 24 most commonly occurring understory species distinguished four assemblages, one for which a pioneer forb species had the highest cover levels, and three others that were characterized by different bryophyte species having the highest cover. Constrained ordination (distance-based redundancy analysis) showed that two above-ground (mean tree diameter, litter cover) and eight below-ground (forest floor pH, plant available boron, microbial community composition and function as indicated by MSIR and PLFAs) properties were associated with variation in understory plant community composition. These results provide novel insights into the important ecological associations between understory plant community composition and heterogeneity in ecosystem properties and processes within forests dominated by a single canopy species. [ABSTRACT FROM AUTHOR]

Site productivity, as affected by soil nutrients and available moisture is often characterized using an edatopic grid. A challenge for forest ecologists and managers working across large areas and in complex landscapes is the need to identify spatially different ecological environments that follow an edatopic classification. Recent advances in remote sensing offer some potential approaches for mapping ecological environments and landscape conditions. It is now feasible to compile long temporal image sequences using Landsat imagery for reconstruction of forest stands and derivation of long term indices of landscape productivity; and the increasing proliferation of airborne laser scanning (ALS) technology also allows for the acquisition of detailed information on topographic elevation and vegetation structure with sub-meter accuracy. In a large area of boreal mixedwood forest in northwestern Alberta, Canada, we examined the utility of using Landsat-derived vegetation greenness (indicating productivity), and ALS-derived cartographic depth-to-water (indicating moisture), to determine forest cover type and vegetation responses following variable retention harvesting. Our results demonstrate that both long-term image sequences from Landsat and ALS-derived topography and vegetation structure act as proxies for edatopic grid components, and are well-suited to differentiating forest cover types. Deciduous-dominated, deciduous-dominated with conifer understory, mixed, and conifer-dominated forests were generally distributed (in order) across a gradient of increasing moisture and decreasing greenness. Landscape greenness was the strongest predictor of vegetation regrowth after disturbance, followed by depth to water and other terrain factors, such as elevation and slope. New advances in, and complementary use of, different remotely sensed information provides a better understanding of both the landscape-scale distribution of forest cover types and patterns of vegetation regrowth following disturbance. [ABSTRACT FROM AUTHOR]

We tested whether direct placement of forest floor material ( FFM: litter, fibric, humus layers and surface mineral horizons) and sowing of a cover crop ( Melilotus officinalis) could facilitate the establishment of native forest understory species at a reclaimed coal mine in Alberta, Canada. FFM was salvaged at two depths (15 and 40 cm) from a recently harvested native aspen forest and immediately placed at the same depths on the reclamation site. Total richness (approximately 61 species in 96 subplots) was similar in each of 3 years post-placement; total richness for all 3 years combined was 87 including 34 typical boreal forest understory species plus 30 other natives. The deeper treatment reduced cover of all species, native and non-native species in year 1. In year 3, the deeper treatment still had lower cover of non-native species but had higher cover of forest understory species in years 2 and 3. The deeper treatment also resulted in lower species richness per plot, but only in year 1. In year 2 (when the biennial clover was at its tall stage), the cover crop treatment was associated with lower cover of non-native species but did not affect the cover of native forest understory species. Direct placement of FFM can help facilitate establishment of a diverse native boreal forest understory in a reclaimed landscape. Although richness and cover may be initially higher with shallower salvage and placement, deeper salvage may ultimately be better for encouraging establishment of native forest understory species. [ABSTRACT FROM AUTHOR]

Abstract: The range expansion of mountain pine beetle (MPB; Dendroctonus ponderosae Hopkins (Coleoptera: Curculionidae, Scolytinae)) from the focal region of the recent major epidemic in British Columbia, Canada to the north and east into Alberta’s lodgepole pine forests may alter the future successional pathway of these forests. Thus, there is a need for an improved understanding of recruitment dynamics of lodgepole pine in both healthy and MPB-attacked stands arising from this shift from a fire-driven disturbance regime to a disturbance regime that also includes MPB. We evaluated the potential impacts of mountain pine beetle attack and associated forest management on the future regeneration potential of lodgepole pine forests in western Alberta. We quantified seedbed availability and advance regeneration, and compared lodgepole pine recruitment of sown seed on five different seedbed types (i.e., moss, shallow organic, deep organic, decayed wood, and mineral soil) within four different stand treatment types that simulated mountain pine beetle attack and forest management disturbance (i.e., control, moderate MPB attack, high intensity MPB attack, and salvage harvest) in the Upper Foothills of western Alberta. Recruitment from sown seed 1–3years after MPB attack was poor (median 0%, 0–2% 5th–95th percentiles) across stand treatment types for moss and both organic seedbed types. Decayed wood and mineral soil were the best seedbed types, with higher recruitment rates than the organic and moss seedbeds, although recruitment was still relatively low (median 0%, 0–6% 5th–95th percentiles). Recruitment rates of seedlings on decayed wood and mineral soil seedbed types increased with increasing levels of disturbance; recruitment was lowest in control stands, higher in the simulated MPB-attack treatments, and highest in the salvage logged stands. However, these favorable seedbeds were scarce among all stand treatment types. Given the extremely low levels of advance regeneration and lack of natural regeneration we observed initially after MPB attack in our study sites, we anticipate that future stand development will be hampered by a lack of lodgepole pine recruitment, at least in the short term. If the goal is a re-stocked forest, significant silvicultural intervention will be required for lodgepole pine forests attacked by MPB within novel habitat ranges in western Alberta. [Copyright &y& Elsevier]

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Presents an study to analyze aerial photographs in order to assess changes in vegetation composition and distribution in the montane ecoregion of Jasper National Park, in the Rocky Mountains of Alberta, Canada. Use of a quantitative approach for assessing relative vegetation change in repeat ground photographs; Consideration of grasslands, shrub, juvenile forest, and open forests; Findings that the coniferous species is dominant.

Reports on changes in terrestrial vertebrate communities from pre- to post-harvest in experimentally created buffer strips (20, 100, 200, and 800 m wide) in a boreal mixedwood forest in Alberta, Canada. Focus on the utility of forested buffer strips as reserves for forest species in managed landscapes; Observations on abundance of small mammals, amphibians, and forest-dependent bird species; Conclusion that 20?100 m buffers would not serve as reserves for forest songbirds in managed landscapes.