Dr. Uldis Silins and Dr. Ellen Macdonald describe vegetation dynamics and hydrological responses to mountain pine beetle (MPB) attacks in Alberta. MPB attacks set up an unique disturbance in forests; the overstory is killed but the understory and soil are not directly affected. So this project studies the affects on water balances and early changes in understory and vegetation and soils.
The study simulated MPB attacks by killing trees with glyphosate (Roundup) in large plots. Partially killed stands transpired almost 10% more than healthy stands because healthy trees in the partially killed stands increased their water use by 33%, masking the lack of transpiration by killed trees. Modelling of large scale impacts showed very large groundwater recharges. Understory vegetation changes early after MPB attacks did not change much from pre-attack composition. Salvage harvest sites did change significantly. Lodgepole regeneration was not good; it was most successful in the salvage harvested sites. They anticipate the most dramatic hydrologic effects after pine needles fall (grey attack stage). But those changes have yet to be monitored and analysed at these sites. Their presentation concludes of a summary of publications available on this project.
Dr. Uldis Silins is a professor of forest hydrology at the Department of Renewable Resources, University of Alberta, Edmonton, Alberta. Dr. Ellen Macdonald is a professor in land reclamation in the Department of Renewable Resources, University of Alberta, Edmonton, Alberta. Their presentation was part of the Foothills Research Institute's Mountain Pine Beetle Research-Practitioner Information Exchange Forum, April 24-25, 2013 at the University of Alberta, Edmonton, Alberta.