In 1989, four single-stem, vegetation-control methods were used on trembling aspen overstory on two study sites, at Prince George and Kelowna North British Columbia. The study compared cost and productivity of four treatments: hack-and squirt, gel cap, EZJect, and girdling. The study also established permanent sample plots and collected baseline data for monitoring the efficacy of treatments and the effect of the treatments on understory plant communities. The project was funded by the federal direct delivery component of the Canada/BC Forest Resource Development Agreement (FRDA).