Native Balsam Poplar Clones for Use in Reclamation of Salt-Impacted Sites

For oil sands mine sites in northern Alberta, the presence of salty Oil Sands Process-affected Water (OSPW), a byproduct of hot-water extracted bitumen, poses a challenge on some reconstructed landforms. The fundamental challenge when revegetating these sites is to ensure not only survival, but vigorous growth, where plants experience conditions of high electrical conductivity in the substrate, due largely to salts deposited from process affected water. Poplars are known for their salt tolerance, and a 2012-2013 greenhouse study conducted by Alberta-Pacific Forest Industries Ltd. (Al-Pac) identified several clones of the native balsam poplar from their controlled parentage program that appear to have a high tolerance to OSPW. This research project tests these clones under field conditions to identify whether or not they are suitable for planting in OSPW influenced soils.

Selected Stream 2 clones (high salt tolerant clones) from the Al-Pac balsam poplar controlled parentage program would be best for reclamation sites. The Syncrude Stream 1 wild lot showed comparable growth performance under “ideal” conditions, but on challenging, salty sites, clones from the Al-Pac selections are recommended. Balsam poplar showed considerable genetic diversity in this study. Screening clones for salt tolerance, and maximizing use of tree improvement program trees available through Al-Pac, while meeting regulations for genetic diversity, could provide a significant reclamation opportunity. Recommendations: (1) continue to monitor to see if high survival and growth rates continue, or if some clones less well adapted to a salty environment close to shore begin to show signs of reduced growth and eventual mortality; and (2) continue to measure the growth (height and DBH) to see if distance from shoreline affects long term growth and survival. Flooding and damage to fine roots near the shore may pose a concern depending on water level.