Impact of Trembling Aspen (Populus tremuloides Michx.) Planting

Aspen seedlings planted on recently reclaimed sites at Imperial’s Cold Lake Operations (CLO) often have poor survival, and when they survive, they often exhibit poor growth. It was hypothesized that competition with grass and other herbaceous weeds may cause poor aspen growth performance, and that increasing planting density may enhance establishment. A study was conducted over four growing seasons (2015-2018) to assess effect of aspen planting density on growth performance at three in situ reclamation sites at Cold Lake Operations (CLO), Alberta, using data on height, Root Collar Diameter (RCD), height/RCD, survival and health of the trees at each site. Different sites were used to determine if results were site specific.

Increasing planting density did not have a consistent, significant effect on both aspen establishment and growth, but there was an indication that higher planting densities provide an advantage in the case of height and RCD growth. It was also clear that site conditions, such as soil density, weather, competition, animal browsing and rodent damage, also have some effect on growth and success of aspen seedling establishment. It would be beneficial to continue monitoring for additional years to see if more trends appear over time.