New Forests

, Volume 37, Issue 2, pp 213–225 | Cite as

Competition control in juvenile hybrid poplar plantations across a range of site productivities in central Saskatchewan, Canada

  • Bradley D. Pinno
  • Nicolas Bélanger


The response of hybrid poplar plantations established on former agricultural land in Saskatchewan to competition from weeds on a range of site productivities was studied. The short-term impact of competition control on the growth of juvenile trees and how tree responses to competition control differed across the productivity gradient was of particular interest, as was the determination of which resource was most highly competed for and was most important in determining tree growth. Eight sets of paired plots in juvenile hybrid poplar plantations were established in central Saskatchewan across a range of site productivities. In each pair, one plot had complete weed control (weed-free) while in the other plot weeds were allowed to grow. The best soil predictor of tree growth was soil texture, represented by a combination of the percentage silt and clay, with finer textures showing better growth. Competition control significantly increased tree growth on all sites with the benefit being greatest on the higher productivity sites. Soil water appeared to be highly competed for between trees and weeds and was a dominant resource controlling growth. For soil nutrients, nitrogen and phosphorous were highly competed for between trees and weeds. However, leaf phosphorous concentration of the weed-free plots had a strong positive relation to tree growth while nitrogen did not, indicating that when trees are free of competition they can access sufficient nitrogen from these soils.


Agricultural soils Productivity Competition control Foliar nutrition Soil moisture Growth rates Leaf weights 



We thank M. Emigh, J. Jackson and N. Roberston for their hard work in the field and laboratory. This study was made possible by financial support from the AFIF Chair in Agroforestry and Afforestation, the University of Saskatchewan and the Natural Sciences and Engineering Research Council of Canada


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Copyright information

© Springer Science+Business Media B.V. 2008

Authors and Affiliations

  1. 1.Department of Soil ScienceUniversity of SaskatchewanSaskatoonCanada
  2. 2.Department of BiologyUniversity of ReginaReginaCanada
  3. 3.UER Sciences et Technologies, TéluqUniversité du Québec à MontréalQuébecCanada

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