Foliar nutrient concentrations and potential limitations of white spruce (Picea glauca (Moench) Voss) in Yukon, Canada

"Although nutrient deficiencies are not uncommon in forests across the north, little is known about these limitations in the Yukon, and even less about how these limitations have been and/or will be affected by climate. To address existing edaphic limitations to forests in the Yukon, an investigation of the nutrient concentrations of white spruce (Picea glauca (Moench) Voss) foliage was undertaken throughout various regions of Yukon in 2009. By comparing individual nutrient concentrations to critical values and reviewing nutrient ratios, the results identified nitrogen (N) as being commonly severely deficient. Phosphorus (P) and sulphur (S) were also commonly deficient, whereas magnesium (Mg) and potassium (K) were mostly adequate with few reports of slight deficiency levels. In contrast, calcium (Ca) was adequate at all locations. Of the micronutrients, zinc (Zn) and manganese (Mn) were the only elements in adequate supply at all sites while slight to moderate deficiencies were commonly indicated for all other micronutrients across the study area. Nutrient limitations may ultimately restrict the growth response of white spruce to climate changes and/or increasing atmospheric CO₂."