In the Upper North Thompson valley at Pyramid Creek, the second-year results of a fertilization trial on Pseudotsuga menziesii (Douglas-fir), Thuja plicata (western red cedar) and Picea glauca x engelmannii (hybrid spruce) have been completed. The study began in the spring of 2002. One hundred planted seedlings of each of the three species in the trial were fertilized with 16-6-8 teabag fertilizer; an additional one hundred seedlings per species were identified as controls. The purpose of the trial is to determine if fertilization at the time of planting will both increase seedling height and caliper, and result in the reduction or elimination of brushing, and promote the achievement of minimum free-growing heights at an earlier date. Second year trial results indicate that all three species continue to have significant responses to fertilization, particularly in relation to height and caliper growth. Hybrid spruce displays the greatest height growth increases, as fertilized stock is 15 percent taller than the control. Fertilized Douglas-fir and western redcedar are 10 and 4 percent taller respectively. In regards to caliper growth, the fertilized hybrid spruce also displays the greatest increase. The ground level diameter (GLD) of fertilized hybrid spruce stock has increased by 18 percent over the control. Fertilized Douglas-fir and western redcedar have also shown considerable increases of 17 and 15 percent respectively. Seedling caliper was measured in the spring of 2003 and average stem caliper was essentially the same between the fall 2002 and spring 2003 measurements. Fertilizer does not appear to cause stems to increase in diameter over the winter months. The results of Foliar Analysis indicate that all of the species generally have increased levels of macro and micronutrients, with Douglas-fir showing the greatest differences between the treatment and control stems, especially with regards to nitrogen. The concentration of foliar nutrients in the fertilized stock, in comparison to the control stock, was notably greater following the first growing season. However, nutrient concentration in the foliage following the second growing season is generally the same between the fertilized and control trees with the fertilized trees having lower levels in many cases. As the fertilized seedlings appear to be utilizing the nutrients for increased growth, second growing season results indicate that the benefits of fertilizer are perhaps better presented by increases in growth and biomass, than by nutrient concentrations derived from foliar analysis. Assessment of competitive status indicates that the fertilized stock experiences reduced competition from vegetation as these stems yielded greater height and caliper growth. The second growing season results indicate the fertilized stock is less impacted. Results from year two indicate that future assessments will confirm the use of teabag fertilization as a method to reduce suppression and mortality due to brush competition through the increased growth of crop trees. It is also predicted that crop trees will achieve minimum free-growing heights at an earlier date than would otherwise be expected. Second Growth Consulting Ltd.
Second Growth Consulting Ltd.. 2004. Teabag fertilization at planting on Pseudotsuga menziesii, Thuja plicata, and Picea glauca x engelmannii: second growing season results - Pyramid Creek. Forest Investment Account (FIA) - Forest Science Program. Forest Investment Account Report. FIA2004MR122