Impact of planting container type on growth and survival of three hybrid poplar clones in central Alberta, Canada

We compared growth performance and survival of three hybrid poplar clones (Walker, Northwest and Okanese) planted as cuttings into five different Styroblock® containers (412A, 415D, 512A, 515A, 615A) with increasing cavity volume and decreasing cavity density under commercial growing conditions at two nurseries in central Alberta, Canada. After 175 days of growth, our results showed considerable variation in growth traits among container types while survival was generally high with an overall average of 89 %. Initial cutting diameter appeared to be an important predictor of survival and our results showed that a cutting diameter of ≥7.5 mm increased survival rates of the tested hybrid poplar planting stock. Furthermore, containers with larger cavity volume and lower cavity density had a strong positive influence on growth and survival across nurseries (R 2 = 0.96). Growth trait interactions with container type showed that container 512A (cavity volume: 220 ml; cavity depth: 12 cm) resulted in more diameter growth across clones. Cavities with a depth of 15 cm (415D, 515A, 615A) resulted in higher root:shoot ratios than cavities with a depth of only 12 cm (412A, 512A), irrespective of cavity volume or cavity density. Lastly, our study identified Okanese as a well-rounded clone with great growth potential both above and below ground. From an operational standpoint, we found container types 512A and 515A the most cost-effective choices under the assumption that nursery space and budgets are limiting factors.