WEYDV-02-068

Use of Flaming to Reduce Competition between Aspen Regeneration and Marsh Reed Grass
Sponsor: 
Weyerhaeuser Company Limited
Lead Researcher: 
J. Karpyshyn and E. Korpela, Alberta Research Council, Alberta
Body: 
The use of fire as a method of vegetation control is often discouraged due to the risk of wildfire. The use of liquefied petroleum gas devices (LPG) can help to mitigate the risk and provide a potential method for the safe integration of fire into current management. This study addresses the efficacy of LPG devices to control marsh reed grass thus providing a competitive advantage to aspen and/or planted conifers.

Research to address the potential of LPG devices to control marsh reed grass included both laboratory and field trials. The laboratory study involved flaming marsh reed grass sod collected from an area adjacent to a pipeline. Initial biomass of the dormant grass was adjusted to three levels of biomass (ie. light, moderate and heavy). The sod was soaked to until moisture levels reached pre-determined levels (ie. dry, moist and soaking). The samples were flamed and placed in a greenhouse to re-grow. After 28 days of growth, the green vegetation was clipped to a height of 1cm and oven-dried. The field component was conducted north of Athabasca, Alberta. The two cutblocks that were utilized for the trial were harvested in summer 2000. Prior to flaming, sticks, fine fuels, green vegetation and duff were sampled for moisture content. The field plots were treated in fall 2000.

The study found that grass re-growth in the laboratory appeared to initiate from seed rather than rhizomes. Because the sample trays were only allowed to re-grow for 28 days prior to being clipped, many of the plants did not have sufficient time to mature and could only be identified at the species level. The greatest length of exposure to flaming (ie. 0.5 mph) decreased forb biomass production significantly. Although the grass biomass decreased with longer exposure to flaming versus no flaming, it is not known what specific effect flaming had on marsh reed grass, since the biomass of each grass species was not individually determined. Although grass biomass production did not significantly change over varying soil moisture conditions, forb biomass production was found to decrease in the wettest treatments. Of interest was the abundance of introduced species that germinated in the laboratory following flaming. The estimated costs of flaming are provided in the final report.

Re-measurement of the field study is scheduled for 2001.