Use of a boundary line approach to determine optimum nutrition levels for three conifers and their application to nutrient diagnosis in the boreal forest

Knowledge of optimum concentrations and ratios of major nutrients in tree foliage is required to assess the nutrient status of the boreal forest. This thesis aimed at determining foliar nutritional standards for white spruce (Picea glauca (Moench) Voss), black spruce (Picea mariana Mill. B.S.P.) and jack pine (Pinus banksiana Lamb.) and to assess the nutrient status of forest stands across Canada for all major nutrients (N, P, K, Ca, Mg and Mn) using critical values (CVA) and compositional nutrient diagnosis (CND). Trees were sampled at three locations in Ontario and Quebec to cover a gradient of soil fertility levels. A boundary line approach was used in combination with quadratic regression models to assess the relationship between growth and foliar nutrient concentrations or CND scores when free of the effects of interacting environmental factors. (Abstract shortened by UMI.