this thesis explores the relationship between the soil nutrient potassium and its effect on red pine growth. this thesis summarizes existing knowledge on differing soils impact on red pine and the lack of polymorphism. the importance of individual nutrient effects on growth determines the overall effect and optimization of amelioration. individual nutrient effects on red pine growth are not available for mature red pine stands and are generally restricted to early growth. although soil texture is not a direct influence on growth, nutrients in the soil impact growth behaviour. this study aims to compare two similar red pine stands in northwestern ontario and determine the statistical difference in diameter and height growth. stands height, diameter, and mortality were cumulatively measured in previous years. the top 15 cm of soil in each plot was measured and a motte® soil sample test was completed to determine the ph, nitrogen, phosphorous, and potassium. the tree growth measurements were compared with soil samples taken randomly in each plot with microsoft excel and spss. our findings showed an increase of 17-22% in diameter, 18- 24% in height, and a decrease of 11% for mortality. our results showed a significant correlation between increased diameter and height growth with an increase in potassium levels. our study revealed that red pine plantations could provide a higher amount of volume through the amelioration of harvested stands.