UBC Theses and Dissertations
Macronutrient deficiency and its effect on coniferous growth Murison, William Forbes
This study was designed to throw some light upon the nutritional requirements of certain commercially important species of the western coniferous forests of Canada. Five species, coastal Douglas-fir (Pseudotsuga menziesii (Mirb.) Franco var. menziesii), interior Douglas-fir (Pseudotsuga menziesii (Mirb.) Franco var. glauca), Engelmann spruce (Picea engelmannii (Parry) Engelm.), ponderosa pine (Pinus ponderosa Dougl.) and western white pine (Pinus monticola Dougl.) were grown in sand cultures in a greenhouse and artificially subjected to macro-nutrient deficiency for a period of nineteen months. The quantitative effects of such deficiencies on shoot and root growth, shoot/root ratios, chlorophyll content, vigor, specific gravity of the wood, foliar content of reducing sugars and foliar content of copper and zinc were studied and described. Chlorotic and necrotic symptoms were compared with the use of a coded color chart and keys to the various deficiencies constructed on the basis of these color comparisons. The foliar symptoms of deficiency were completely documented by color photography. A concurrent study of the growth of the same five species on four different soil types was also undertaken. Apart from affording useful information on the suitability of the soils for the growth of the species studied, this portion of the experiment confirmed the fact that the sand culture technique is an acceptable experimental method for growing conifers. The concept of tolerance was discussed and a method proposed for its objective determination. In essence, then, this study established a dependence between five coniferous species and an adequate supply of macrometabolic elements for normal development and growth. The imposition of deficiencies of any one of six elements studied resulted in reduced growth and arrested development. Quantitative and qualitative confirmation is given of the reality of these effects.
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