Projecting height growth of understory Picea glauca in stands with an overstory dominated by Populus tremuloides

Development of height growth projection models will assist in management of mixedwood stands. Plots were established in stands with an overstory dominated by trembling aspen (Populus tremuloides Michx.) and an understory with white spruce (Picea glauca (Moench) Voss) present.; Non-linear regression analysis was utilized to examine the relationship between understory white spruce height increment and potential individual explanatory factors. Relative crown length, breast height age, and overstory tree spacing factor showed the strongest correlation to height increment. Based on these variables a multiple regression model was built to project future height increments.; The importance of relative crown length (RCL) for predicting height increment resulted in the need for a model to predict RCL. The final RCL model included breast height age, overstory coniferous spacing factor, and deciduous spacing factor as explanatory variables. The height increment and RCL models were then jointly incorporated for use in the Mixedwood Growth Model (MGM).