Vegetation and Soil Characteristics in Reclaimed Areas on the Suncor Lease

During the 2010 monitoring year, Suncor initiated a pH study on Dyke 4 to investigate whether the pH differences observed from 1996 to 2008 were localized near one of the monitoring transects or extended along the entire dyke. The study aimed to answer three key questions: what is the pH along the length of Dyke 4, where does the pH gradient change, and what causes the pH differences. In 2011, two representative sampling locations—D4-19 (neutral pH) and D4-5 (extreme acidity)—were selected to further explore the relationship between soil pH and vegetation performance. This follow-up study focused on determining the pH at these sites and assessing its effects on jack pine tree growth and ground vegetation development.

From 1996 to 2008, baseline soil and vegetation monitoring along Dyke 4 revealed consistent differences between transects D4-1 and D4-2, with D4-1 exhibiting persistently lower, more acidic pH levels. These acidic conditions, likely caused by the use of peat material during reclamation, influenced vegetation development—initially favoring agronomic species on D4-1 but eventually supporting greater tree and shrub growth, particularly lodgepole pine, which tolerates low pH. Soil sampling in 2010 confirmed ongoing acidity near D4-1, with several sites classified as having Very Strong to Extreme acidity, which can reduce forest productivity and limit the establishment of pH-sensitive species. By 2011, further assessments reinforced the impact of soil pH on reclamation success, showing significantly better vegetation and tree growth at less acidic sites like D4-19, while moss cover and acidic conditions continued to shape the ecological trajectory of D4-1.