Vertical Gradients In Photosynthetic Gas Exchange Characteristics And Refixation Of Respired CO2 Within Boreal Forest Canopies

  • Sites: CA-Man, CA-Oas, CA-Obs, CA-Ojp
  • Publication Type: JOUR
  • Authors: Brooks, J. R.; Flanagan, L. B.; Varney, G. T.; Ehleringer, J. R.

  • We compared vertical gradients in leaf gas exchange, CO2 concentrations, and refixation of respired CO2 in stands of Populus tremuloides Michx., Pinus banksiana Lamb. and Picea mariana (Mill.) B.S.P. at the northern and southern boundaries of the central Canadian boreal forest. Midsummer gas exchange rates in Populus tremuloides were over twice those of the two conifer species, and Pinus banksiana rates were greater than Picea mariana rates. Gas exchange differences among the species were attributed to variation in leaf nitrogen concentration. Despite these differences, ratios of intercellular CO2 to ambient CO2 (ci/ca) were similar among species, indicating a common balance between photosynthesis and stomatal conductance in boreal trees.


  • Journal: Tree Physiology
  • Funding Agency: —
  • Citation Information:
  • Volume: 17
  • No: 1
  • Pages: 1-12
  • Publication Year: 1997/01/01
  • DOI: 10.1093/treephys/17.1.1