Noabur, MR, Kimaro, AA: Schoenau, JJ & Salifu, KF 2013, 'Response of aspen and white spruce seedlings to fertilisation on a reconstructed oil sands site in Alberta, Canada', in M Tibbett, AB Fourie & C Digby (eds), Mine Closure 2013: Proceedings of the Eighth International Seminar on Mine Closure, Australian Centre for Geomechanics, Cornwall, pp. 377-388, https://doi.org/10.36487/ACG_rep/1352_31_Noabur (https://papers.acg.uwa.edu.au/p/1352_31_Noabur/) Abstract: Every year, oil sands mining in Alberta, Canada, results in a significant area of degraded land, which needs to be reclaimed. One of the sustainable reclamation strategies for a post-mining site is reforestation. In reconstructed mine sites, establishment of mixedwood boreal tree seedlings like trembling aspen (Populus tremuloides Michx) and white spruce (Picea glauca) along with ground cover is helpful to stabilise soil, minimise erosion and promote native vegetation restoration. Barley (Hordeum vulgare L.) and oats (Avena sativa) are the ground cover species that have been recommended for oil sands reclamation operations, but interactions of planted tree seedlings with ground cover and the growth response to fertilisation are not clearly understood. This study evaluated the effect of different rates of nitrogen (N), phosphorus (P) and potassium (K) fertiliser on the survival and growth of tree seedlings that were planted without and with barley and oats as ground cover. A lower survival rate was recorded for trembling aspen in response to N,P,K fertilisation. Trembling aspen was more sensitive than white spruce to ground cover competition and was negatively affected by barley and oats, especially with added fertiliser. Height, root collar diameter increment and root and shoot biomass yield of trembling aspen were significantly decreased when planted with ground cover, whereas white spruce was not affected. In general, adding fertiliser to these systems appears to be of very little benefit in enhancing the early establishment and growth of tree seedlings.