Plantations of hybrid poplar are used by the pulp industry of Canada to increase fiber supply, reduce transportation costs, and decrease dependence on naturally forested land. Alberta-Pacific (Al-Pac) Forest Industries Inc. has established hybrid poplar plantations on ~8,000 ha of land previously used for agriculture. With a target rotation of less than 20 years it is important that these plantations be managed for maximum biomass, which includes minimizing the impact of weeds.
Competitive pressure from weeds within poplar plantations is a primary reason that many trees fail to reach their full growth potential. However, there is little information available on the impact of weed composition, abundance, or spatial relations to the well-being of nearby trees. During the growing seasons of 2011 and 2012, the I quantified the influence of these factors on the growth of hybrid poplar saplings. My results indicate that site and the initial tree size after the first partial growing season following planting may be just as important as competing weeds as factors influencing tree growth for the next two years. Nonetheless, my analyses also show that perennial grasses are an especially harmful weed towards trees, and are especially so when they are right next to the tree bole. Conversely, perennial forbs seem to influence tree growth very little and attempts to control them using standard business-as-usual silvicultural practices has little resulting influence on tree growth - thus in these cases less intensive management methods may be more cost effective. For plantations with high abundances of competitive grass and annual forbs the story is different and the standard approach appears works best for keeping the trees growing at an acceptable rate.
*This website was made in partial fulfillment of course requirements for RENR 690 Multivariable Statistics
Competitive pressure from weeds within poplar plantations is a primary reason that many trees fail to reach their full growth potential. However, there is little information available on the impact of weed composition, abundance, or spatial relations to the well-being of nearby trees. During the growing seasons of 2011 and 2012, the I quantified the influence of these factors on the growth of hybrid poplar saplings. My results indicate that site and the initial tree size after the first partial growing season following planting may be just as important as competing weeds as factors influencing tree growth for the next two years. Nonetheless, my analyses also show that perennial grasses are an especially harmful weed towards trees, and are especially so when they are right next to the tree bole. Conversely, perennial forbs seem to influence tree growth very little and attempts to control them using standard business-as-usual silvicultural practices has little resulting influence on tree growth - thus in these cases less intensive management methods may be more cost effective. For plantations with high abundances of competitive grass and annual forbs the story is different and the standard approach appears works best for keeping the trees growing at an acceptable rate.
*This website was made in partial fulfillment of course requirements for RENR 690 Multivariable Statistics