Stem Respiration Data

for the Walker Branch Throughfall Displacement Experiment (TDE)


1.0 DOCUMENT INFORMATION
1.1 Document Title: TDE stem respiration data
1.2 Revision Date:  September 23, 2002
1.3 Document Summary:  Stem respiration on mature trees during 1993 through 2000.
1.4 Sponsor: Office of Biological and Environmental Research, U. S. DOE

 2.0 INVESTIGATOR
2.1 Investigator and data set contact:

N.T. Edwards (edwardsnt@ornl.gov)
Research Staff Member
Environmental Sciences Division
Oak Ridge National Laboratory
P.O. Box 2008, Building 1059
Oak Ridge, TN 37831-6422
2.2 Title Of Investigation:
Walker Branch Throughfall Displacement Experiment (TDE)

 3.0 DATA SUMMARY
Stem respiration data for four dominant tree species on the TDE site: Acer rubrum, Liriodendron tulipifera, Quercus alba, and Quercus prinus.

 4.0 PROCEDURES
Stem respiration measurements were taken on 18 mature trees each of Acer rubrum L. (red maple), Quercus prinus L. (chestnut oak)  and Quercus alba L. (white oak) at intervals during several months prior to establishment of the TDE in 1993 and continuing through 1996. Measurements were taken on 18 mature Liriodendron tulipifera L. yellow poplar trees at intervals in 1998 through 2000.  Trees were selected to provide a wide range of dbh sizes within each treatment and within each species.    All respiration measurements in 1993, except for one very late in the growing season and one during the dormant season, were taken prior to the beginning of water manipulation.  Six overstory trees of each species were selected on each of the three TDE treatment plots.   An effort was made to select trees in each treatment over a range of slope positions.  This was not possible for yellow poplar because this species primarily occupied lower slope positions.  Most of the data were collected during the growing season (April through August), but some measurements were made during the dormant season each year.  Measurements were made with a closed infrared gas analysis system and modifications of previously described techniques ( Edwards and Hanson 1996).  A flat rectangular frame (17.5 cm wide x 35 cm long) made of 3-mm-thick and 3-cm-wide aluminum was attached with two small aluminum nails to each tree approximately 1.5 m above the ground. Spaces between the frame and the tree were filled with insulating foam.  After the foam dried, it was trimmed to the shape of the frame, thus creating an open chamber (12.5 cm wide x 29.5 cm long) on the side of each tree. The  frames provided a uniform base for attaching an 1825-ml aluminum cuvette  for isolating the interior from the outside air and creating a volume from which stem CO2-exchange rates could be measured. Sapwood temperature was measured during each respiration measurement with a thermocouple inserted just deep enough to penetrate the cambium.

 5.0 OBSERVATION NOTES
Stem respiration and temperature measurements were taken on the north side of the trees.  Sapwood thicknesses were determined from increment cores taken a few centimeters below the respiration chambers.

 6.0 DATA ORGANIZATION

Data are provided in comma delimeted csv files where the first line includes the variable names and subsequent lines include the following data by year.

6.1 Variable, Definition, and Units

6.2 Number of Records: 1639 measurements.

6.3 Missing data: none

6.4 Related Data Sets:  Data sets on branch respiration and sapling respiration are also available but on a much more limited basis.

7.0 KNOWN ERRORS AND QUALITY ASSESSMENT
The number of trees does not always equal 6 per species per treatment.  Chamber leaks and other sampling errors resulted in the exclusion of some measurements.

8.0 NOTES

8.1 Limitations of the data:   Care should be taken in attempting to quantify stand level stem respiration from these data alone because rates vary within each tree (e.g. branch respiration tends to be higher than stem respiration especially when expressed per unit volume).

8.2 Known Problems With The Data:     None.

8.3 Usage Guidance:     None.

 9.0 REFERENCES:

Edwards NT, Hanson PJ (1996) Stem respiration in a closed-canopy upland oak forest. Tree Physiol 16:433-439.

Edwards NT, Wullschleger SD (2000)  Carbon dioxide efflux rates from stems of mature Quercus prinus L. and Acer rubrum L. trees do not appear to be affected by sapflow rates.  Jf Sustain For 10(?):125-131.

Edwards, N.T. and P.J. Hanson. 2003  Above-ground autotrophic respiration. Chapter 4 in P.J. Hanson and S.D. Wullschleger, Eds. North American Temperate Deciduous Forest Responses to Changing Precipitation Regimes. Springer, New York, pp. 48-66.

 10.0 DATA LISTING

Click on the following to view data for the listed year.
Once open the files can exported as text files with the 'Save As' command.

Boleresp.csv