|Alberta-Pacific Forest Industries Inc.
Object & Deliverables
This project focused on mixes of White spruce (Picea glauca (Moench) Voss) and Western Aspen (Populus tremuloides Michx.), monitoring how they perform under different growing conditions. The project was a five-year study on the affects of nutrients and moisture, as well as different soil conditions, on plant growth and physiological parameters. The experiment was conducted in the Aspen Parkland natural region near Vegreville, Alberta. The principle objectives for the project were determining if there is a direct nutritional interaction between aspen and white spruce through mycorrhizae connection, and establishing whether aspen and white spruce have different resource utilization regimes when grown in different resource conditions and compositional mixes.
The study was conducted within a three-way randomized block design and replicated three times. Treatment combinations were species mix (proportions of spruce and aspen), irrigation (yes or no), and fertilizer (yes or no), which resulted in 20 combination treatments. Trees were measured annually for diameter, height, crown diameter, leaf area index, fluorescence, and photosynthetically active radiation. Soil moisture content was monitored approximately every two weeks.
Results indicated that maximum volume per hectare appeared to occur when the aspen component was about 20% with white spruce at 80% of the stand by density. Implications for climate change suggested greater mortality and reduced growth of both aspen and spruce in the event of drier climatic conditions. Given the high abundance of mixed aspen-white spruce stands across Alberta’s forests, it is important that the correct management steps are taken to ensure the highest productivity of both species.