ALPAC-01-018

Growth and Physiology of Early Establishment of Poplars in Northeastern Alberta
Sponsor: 
Alberta-Pacific Forest Industries Inc.
Lead Researcher: 
Annie DesRochers, PhD, University of Quebec, Barb R. Thomas, PhD, Alberta-Pacific Forest Industries Inc.
Body: 
This report summarizes the results of various trials focused on the growth and physiology of planted poplars. The project began in November 2000 and was completed in May 2003.The project objectives were to:
1. Develop a methodology to maximize rooting success of dormant cuttings.
2. Develop a first year fertilizer application strategy for hybrid poplar plantations.
3. Optimize site preparation techniques (different types of mounding) to enhance the growth and establishment of poplars.
4. Investigate the relationships between fertilizer application, leaf nutrient status, water-use efficiency and gas exchange traits.There were 13 trials established to gather the data necessary to achieve the project objectives. Trial results demonstrated improved nursery production by increasing rooting success of dormant cuttings by 35 percent. As well, optimal unrooted cutting size for direct plant was determined to be 25-30cm in length, and the use of balsam poplar cuttings to reclaim roads proved viable.

The fertilization combinations tested did not significantly improve growth and in some cases reduced growth. Greenhouse testing showed that growth can be increased by selecting ammonium-N or nitrate-N depending on soil pH.

Mounding was found to extend the growing season by 2-3 weeks, however it also decreased surface soil moisture and decreased survival by 10 percent. The increased mortality can be reduced by avoiding mounding sites susceptible to drought conditions. Mounding with the incorporation of mill bio-solids was found to significantly increase soil moisture and overall growth of plantations.

The addition of nitrogen increased drought stress resulting in growth reduction. In the field trials, the no-fertilizer treatment significantly increased growth. It was not possible to establish a relationship between gas exchange traits and field performance. In the greenhouse, nitrogen fertilization increased net assimilation, nitrogen content and growth.