Regeneration of aspen following partial and strip understory protection harvest in boreal mixedwood forests

Trembling aspen regeneration was studied in 2 types of partial harvest systems designed to harvest mature aspen but pro- tect immature spruce and encourage natural aspen regeneration. Two partial harvest systems, where the residual aspen was either left in strips or was dispersed uniformly, were compared to traditional clearcuts. After the first and second year since harvest, aspen sucker density and growth was similar between the 2 partial harvests, but was much lower than in the clearcuts. However, in the partial cuts the regeneration density was very much dependent on the location relative to residual trees. The density of regeneration was inversely related to the basal area of residual aspen; however, sucker height was inversely related to the basal area of the residual spruce. Although there were adequate numbers of suckers after partial harvest, their viability and contribution to the long-term productivity of these mixedwood stands is not clear

A partial deciduous canopy, coupled with site preparation, produces excellent growth of planted white spruce

Survival and growth of planted white spruce (Picea glauca (Moench) Voss) were assessed at year 15, in boreal mixedwood stands of northern Alberta, Canada, in stands that were deciduous-dominated prior to logging or conifer-dominated. Three overstory retention levels (0%, 50%, and 75% retention) and four site preparation treatments (mound, high speed mix, scalp, and no treatment) were evaluated. In deciduous-dominated stands, planted spruce performed best in the 50% retention; here, stem volume was at least double that of any other retention treatment after 15 years. In contrast, spruce had reduced growth in coniferous-dominated stands in both 50% and 75% retention treatments compared with the 0% retention. Survival of planted spruce was unaffected by level of retention, but survival was lower in coniferous-dominated stands than deciduous- dominated stands; in the coniferous-dominated stands, survival was better with mounding and mixing and lowest with scalp treatments. All height variables tended to be greater in the mix and mound site preparation treatments. Finally, the best estimates of future total growth (regenerated spruce and deciduous combined) in the coniferous-dominated stands were in the clearcut treatment. In terms of regenerated spruce growth, the best estimates occurred in the deciduous-dominated-50% retention, planted with soil mixing/mounding treatments, where projected growth of spruce was comparable to open-grown and tended stands in Alberta boreal forests.The accepted manuscript in pdf format is listed with the files at the bottom of this page. The presentation of the authors' names and (or) special characters in the title of the manuscript may differ slightly between what is listed on this page and what is listed in the pdf file of the accepted manuscript; that in the pdf file of the accepted manuscript is what was submitted by the author

A nutrient-based sustainability assessment of purpose-grown poplar and switchgrass biomass production systems established on marginal lands in Canada

Sustainability of purpose-grown biomass production on marginal lands in Canada is uncertain. In this study, an assessment of biomass yield and sustainability was performed for two poplar clones (Poplus deltoides x P. nigra, DN-34 – PDN, and P. nigra x P. maximowiczii, NM-6 – PNM) and two switchgrass cultivars (Panicum virgatum cv. Cave-in-Rock – SGC, and Panicum virgatum cv. Nebraska – SGN) on three marginal lands in Guelph (Ontario), Kemptville (Ontario) and Nappan (Nova Scotia) in Canada. The differences in stem biomass across sites were not significant however, differences in stem biomass among plants were statistically significant between poplar and switchgrass (pThe accepted manuscript in pdf format is listed with the files at the bottom of this page. The presentation of the authors' names and (or) special characters in the title of the manuscript may differ slightly between what is listed on this page and what is listed in the pdf file of the accepted manuscript; that in the pdf file of the accepted manuscript is what was submitted by the author

Improved Skin Test for Differential Diagnosis of Bovine Tuberculosis by the Addition of Rv3020c-Derived Peptides

A peptide cocktail derived from the mycobacterial antigens ESAT-6, CFP-10, and Rv3615c allowed differentiation between Mycobacterium bovis-infected and M. bovis bacillus Calmette-Guérin (BCG)-vaccinated cattle when used as a skin test reagent for a “DIVA” test (i.e., a test capable of differentiating infected and uninfected vaccinated animals). Addition of the antigen Rv3020c improves the diagnostic sensitivity without compromising specificity in the face of BCG or Johne's disease vaccination