Weyerhaeuser Company Ltd. (Weyco), initiated a research trial in 2001 to determine if nitrogen (N) fertilizer would reduce the time it takes for high elevation spruce plantations to achieve legislated green-up height requirements. Two previously harvested cutblocks which had not reached green-up height in 2001 were sampled from Weycos operating areas in Kamloops and Lumby. Re-measurements in the fall of 2005 have permitted the 3-year growth response to be quantified. For the Kamloops location, green-up has been achieved for all treatments by the end of the 2005 measurement. There has been a significant 3-year growth response due to fertilizer. Green-up height is estimated to be reached approximately 1-year sooner in the moderate fertilizer treatment, and approximately 11/2 years sooner in the high fertilizer treatment, in order for a stand to increase its green-up height by 1 meter. There has also been an increase in the frequency of insect damage (primarily spruce gall aphid) between 2001 and 2005, but this does not appear related to treatment. For the Lumby location, green-up height has not yet been achieved for any fertilizer treatment by the end of the 2005 measurement. There has not been a significant 3-year growth response between treatments and green-up height is estimated to be reached at the same time regardless. The majority of trees have remained healthy between 2001 and 2005. There is an apparent trend of increased mortality with fertilizer, but this observation has not been evaluated statistically. Based on the limited growth responses from this research trial at both the Kamloops and Lumby locations, the application of nitrogen fertilizer to reduce the time to green-up on high elevation spruce (Sx) sites is not recommended.
J.S. Thrower & Associates Ltd.
J.S. Thrower and Associates Ltd., Landmark Forest Management Ltd.. 2006. Fertilizer trial in high elevation spruce plantations: three-year growth response. Forest Investment Account (FIA) - Land Base Investment Program - Innovative. Forest Investment Account Report