The BOREAS Information System
Terrestrial Ecology (TE)


TE-2: Autotrophic Respiration in Boreal Ecosystems


P.I.(s): Michael G. Ryan -- United States Department of Agriculture (USDA)
Collaborator(s): Michael Lavigne -- Forestry Canada

Objectives: Because respiration increases exponentially with temperature, and because warming is expected to be the greatest at high latitudes, autotrophic respiration strongly affects dry-matter production and carbon storage in boreal forests. The research will:

  1. estimate instantaneous and annual fluxes of CO2 from all respiration for the footprint of tower flux measurements in three ecosystem types (Spruce, Jack Pine, Aspen) at the two BOREAS study areas
  2. test the use of tissue nutrient content as a general estimator of CO2 flux from respiration
  3. use paired comparisons at the two locations to determine whether respiration rates differ with genotype
  4. estimate an annual carbon budget for these sites (in cooperation with other scientists) to determine whether the ratio of respiration to photosynthesis differs among species and climates
Results from these investigations will be used to develop better models for estimating CO2 flux from autotrophic respiration, and clarify of autotrophic respiration in regulating productivity and carbon storage in ecosystems.

TE-2 Pictures

TE-2 prepares for a night raid

TE-2 Data Sets

  • Leaf Respiration
  • Leaf Conductance
  • Bole Respiration
  • Leaf Nitrogen
  • Wood Nitrogen
  • Sapflow

  • Get some TE-2 data using FTP (BOREAS Investigators only, password required). [FTP Help]

    TE-2 BOREAS Operations 1994


    Objectives:

    1. to measure CO2 efflux from autotrophic respiration from foliage, stems, branches, coarse roots, and fine roots in the major forest ecosystem types of the boreal forest
    2. to develop relationships between autotrophic respiration, tissue characteristics (N, P, C, growth), and environment (temperature) to scale cuvette measurements to the ecosystem
    3. to estimate instantaneous and annual fluxes of CO2 from autotrophic respiration for the footprint of tower flux measurements
    4. to use paired species comparisons at the two locations to determine whether respiration rates acclimate to different climates
    5. to estimate an annual carbon budget for these sites (in cooperation with other scientists) to determine whether the ratio of respiration to photosynthesis differs among species and for different climates.


    Types of Data Collected:

    1. CO2 efflux from tree stems and stem and air temperature (continuous diurnal measurements, 3-6 days per IFC) and wood growth, sapwood volume, and N, P, C, and starch and sugar content of sapwood after IFC-3.
    2. CO2 efflux from fine roots (< 2mm diameter) and foliage (at night), and tissue temperature, N, P, C, starch, sugar, mass, area (foliage) for each sample.
    3. CO2 efflux from branches and coarse roots and stem and air temperature and wood growth, sapwood volume, and N, P, C, and starch and sugar content of sapwood after IFC-3.
    4. CO2 efflux from foliage and foliage growth, C, N, P, starch, sugar, temperature.
    5. Estimates of bole photosynthesis for aspen using shaded and unshaded chambers.


    Summary of Places and Times of Measurements:
    Stem, foliage, and fine root respiration were collected at OBS, OA, OJP, YJP in NSA and OBS, OA, OJP, YJP, YA in SSA each IFC and also after IFC-3. Stem respiration was also collected at OBS, OA, OJP, YJP in NSA approximately every two weeks from 6/1 - 9/30. Stem respiration was also collected continuously at SSA-OBS between IFC-2 and IFC-3. Branch and coarse root respiration were measured only at NSA and only during IFC-3. Foliage respiration and foliage expansion was measured every 5-14 days from 5/28- 9/16 (depending on expansion rates) near NSA-Fen on aspen, black spruce, jack pine, alder, and birch.

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    Last Updated: October 29, 1997