BOREAS TE-09 In Situ Diurnal Gas Exchange of NSA Boreal Forest Stands Summary The purpose of the BOREAS TE-09 study was threefold: 1) to provide in situ gas exchange data that will be used to validate models of photosynthetic responses to light, temperature, and carbon dioxide (CO2); 2) to compare the photosynthetic responses of different tree crown levels (upper and lower); and 3) to characterize the diurnal water potential curves for these sites to get an indication of the extent to which soil moisture supply to leaves might be limiting photosynthesis. The gas exchange data of the BOREAS NSA were collected to characterize diurnal gas exchange and water potential of two canopy levels of five boreal canopy cover types: young jack pine, old jack pine, old aspen, lowland old black spruce, and upland black spruce. These data were collected between 27-May-1994 and 17-Sep-1994. The data are provided in tabular ASCII files. Table of Contents * 1. Data Set Overview * 2. Investigator(s) * 3. Theory of Measurements * 4. Equipment * 5. Data Acquisition Methods * 6. Observations * 7. Data Description * 8. Data Organization * 9. Data Manipulations * 10. Errors * 11. Notes * 12. Application of the Data Set * 13. Future Modifications and Plans * 14. Software * 15. Data Access * 16. Output Products and Availability * 17. References * 18. Glossary of Terms * 19. List of Acronyms * 20. Document Information 1. Data Set Overview 1.1 Data Set Identification BOREAS TE-09 In Situ Diurnal Gas Exchange of NSA Boreal Forest Stands 1.2 Data Set Introduction The gas exchange data of the BOReal Ecosystem-Atmosphere Study (BOREAS) Northern Study Area (NSA) were collected to characterize diurnal gas exchange and water potential of two canopy levels of five boreal canopy cover types: young and old jack pine (Pinus banksiana Lamb.), old aspen (Populus tremuloides Michx.), and lowland and upland black spruce (Picea mariana (Mill) B.S.P.). These data were collected between 27-May-1994 and 17-Sep-1994. 1.3 Objective/Purpose The purpose of this study was threefold: 1) to provide in situ gas exchange data that will be used to validate models of photosynthetic responses to light, temperature, and carbon dioxide (CO2); 2) to compare the photosynthetic responses of different tree crown levels (upper and lower), and 3) to characterize the diurnal water potential curves for these sites to get an indication of the extent to which soil moisture supply to leaves might be limiting photosynthesis. 1.4 Summary of Parameters Net photosynthesis, stomatal conductance to water vapor, stomatal conductance to CO2 , transpiration, water use efficiency, mesophyll conductance, photosynthetically active radiation (PAR), air and leaf temperature, CO2 concentration, relative humidity, vapor pressure, vapour pressure deficit (VPD), barometric pressure, and water potential. 1.5 Discussion The gas exchange data of the BOREAS NSA were collected to characterize diurnal gas exchange and water potential of two canopy levels of five boreal canopy cover types: young and old jack pine, old aspen, lowland old upland black spruce. These data were collected between 27-May-1994 and 17-Sept-1994. 1.6 Related Data Sets BOREAS TE-09 PAR and Leaf Nitrogen Data for BOREAS NSA Species BOREAS TE-09 NSA Photosynthetic Capacity and Foliage Nitrogen Data BOREAS TE-09 NSA Leaf Chlorophyll Density BOREAS TE-09 NSA Photosynthetic Response Data 2. Investigator(s) 2.1 Investigator(s) Name and Title Hank Margolis, Ph.D. Universite Laval Faculte de foresterie et geomatique Pavillon Abitibi-Price 2.2 Title of Investigation Relationship between measures of absorbed and reflected radiation and the photosynthetic capacity of boreal forest canopies and understories. 2.3 Contact Information Marie R. Coyea, Ph.D. Universite Laval Faculte de foresterie et geomatique Pavillon Abitibi-Price Sainte-Foy, Quebec Canada (418)656-2131 marie.coyea@sbf.ulaval.ca 3. Theory of Measurements The gas exchange measurements were made with a closed portable photosynthetic system (LiCOR LI-6200). As described in the LI-6200 Primer Manual, it contains three major components: a leaf chamber, within that temperature and humidity measurements are made; the LI-6250, an infrared gas analyzer (IRGA) which measures CO2 concentration and flow rate; and a control console. Air temperature, leaf temperature, and relative humidity are measured in the leaf chamber. The pump in the LI-6250 circulates air from the chamber to the analyzer, where CO2 concentration is measured, and returns it to the chamber. The air flow through the LI-6250 can be diverted through soda lime to remove CO2 for purposes of calibration. The flow valve is used to force some fraction of the flow through a tube of desiccant, which dries the air. This proportional control feature is used to help maintain a steady humidity in the chamber during a measurement. The flow rate of the air going through the desiccant is measured by a flow meter. The IRGA can be used for absolute or differential measurement of CO2. As used with the LI-6200, however, it is configured for absolute measurements. The methodology for measuring leaf area is described in Appendix K of the Experiment Plan, Version 3.0. Aspen foliage is expressed as hemisurface area leaf area, while conifer foliage is expressed as total surface area leaf area. The optical image analysis system (Decagon AgVision System) is an image analysis system that works by first looking at an object through a video camera, then processing the image into discrete numerical information with a digitizer and microcomputer, and finally displaying the image or other information on a monitor for examination. For the measurement of Y (please note that in the text below, "Y" is the Greek symbol psi that is generally used for water potential) response at high (less negative) Y, the cut end of the stem was connected to a water reservoir. For lower (more negative) Y, the branches were taken out of water and the cut surface of the stem was dried and sealed with silicone grease. The branches were then exposed to light and permitted to transpire freely in an open space where the air was stirred continuously using an electric fan. Sealing the cut surface of the branch allowed the branch to maintain a negative pressure inside the xylem while transpiration continued. A pair of branches was chosen randomly at various times for gas exchange measurement at 20§ C. The transpiration rate of the branch being measured was kept very low by maintaining a high humidity in the cuvette (VPD < 0.8 kPa). It took from 3 to 6 hours for branches to reach their minimum Y. Immediately after the gas exchange measurement, the stem of the branch was cut and the water potential was measured with a pressure chamber (Model 610, PMS Instrument Inc., Corvallis, OR, USA). By controlling the time interval between measurements, a range of water potentials was achieved for black spruce and jack pine during both Intensive Field Campaign (IFC)-2 and IFC- 3. 4. Equipment 4.1 Sensor/Instrument Description LI-6200 portable gas exchange system (LI-COR), pressure chamber (PMS Instrument Co.), drying oven, optical image analysis system (Decagon Devices Inc., Pullman, WA), top loading weighing balance, IBM or compatible computer. 4.1.1 Collection Environment Gas exchange and water potential measurements were measured by persons on the upper and lower levels of canopy access towers. In the YJP stand, only 3 m ladders only were necessary. Leaf area measurements were determined in the lab. 4.1.2 Source/Platform Gas exchange and water potential measurements were measured by persons on the upper and lower levels of canopy access towers. In the YJP stand, only 3-m ladders were necessary. Leaf area measurements were determined in the lab. 4.1.3 Source/Platform Mission Objectives The purpose of this study was threefold as outlined in the BOREAS Experiment Plan, Version 3.0, Appendix N, page N-34): 1) To describe the diurnal patterns of stomatal conductance, photosynthesis, and leaf water potential of the principal forest types present at the BOREAS NSA and to determine the precise nature of the environmental controls on these variables. 2) To understand how these physiological properties and their environmental controls are influenced by canopy position and period of the growing season. 3) To use these data for partial model validation with a model parameterized from laboratory data to be compared eventually to flux tower data from the NSA. 4.1.4 Key Variables Diurnal water potential and net photosynthesis. 4.1.5 Principles of Operation Gas exchange measurements were taken with a LI-COR 6200 system. Generally, a branch (bearing leaves) section was placed into the cuvette for three 20 second measurements. The same branch section was measured periodically throughout the day (approximately once every hour). At the end of the day, these branch sections were harvested and stored in a freezer until leaf area was determined. The volume displacement method (Appendix K of BOREAS Experiment Plan, version 3.0) was used to measure leaf area of conifer needles. The optical image analysis system was used to measure needle lengths and aspen projected leaf areas. Water potential measurements were simultaneously taken with a pressure chamber on randomly selected branch sections at the same canopy level as the photosynthetic measurements. These samples were not kept for any further analyses. 4.1.6 Sensor/Instrument Measurement Geometry Measurements were taken at two canopy levels: top and bottom. The heights of these samples varied according to the location of the canopy access tower; however, they reflected the average canopy as described in Section 2.2.3.1 of the BOREAS Experiment Plan, Version 3.0. Because the canopy access towers moved between IFC periods, the canopy levels were not always exactly the same. For example, the measurements at the old aspen stand ranged from approximately 13-15 m for the upper canopy and 9-11 m for the lower canopy. 4.1.7 Manufacturer of Sensor/Instrument LI-6200 portable gas exchange system LI-COR P.O.Box 4425, 4421 Superior St., Lincoln, NE 68504 (800) 447-3576 Pressure Chamber, Model 610 PMS Instrument Co. 480 SW Airport Avenue Corvallis, OR 97333 503-752-7926 Leaf area measurement system/optical image analysis system (AgVision, Monochrome system, root and leaf analysis) Decagon Devices, Inc. P.O. Box 835 Pullman, WA99163 (800) 755-2751 IBM DX2/486 Computer IBM, Inc. 4.2 Calibration The LI-COR LI-6200 was sent to the manufacturer for calibration and general maintenance in February 1994 before field work began (big mistake, see Section 10.1). The LI-6200 was examined daily for page parameters, operating parameters, and clock setting; quantum sensor calculation constant; CO2 analyzer calculation list; flow meter calculation list; relative humidity sensor calculation list; and analyzer reference. Each sensor was checked daily and periodically to make sure it was responding as expected: quantum sensor; air and leaf temperature match; IRGA temperature; flow meter; CO2 concentration; and relative humidity. The zero and span for the CO2 analyzer were set daily. The flow meter was zeroed frequently. The LI-6250 CO2 gas analyzer was calibrated daily according to instrument specifications (CO2 levels), while system tests (e.g., leak tests, boundary layer resistance, soda lime test, and desiccant (k) test) were conducted periodically throughout each sampling day. Approximately every half hour, the desiccant tube was shaken. Daily, the chambers were cleaned and the batteries recharged. The foam pads in the chamber were changed after frequent usage and any noticeable damage. The optical image analysis system was calibrated according to instrument specifications each time the system was opened or after it was left for a period of time. A fine ruler and flat disks of known area were used in the calibration. The pressure chamber was inspected at the manufacturer's facility prior to field use. Safety checks were conducted from time to time throughout the sampling period. 4.2.1 Specifications The weighing balance was accurate to within 0.0001 g. The leaf area system was accurate to within 1%. The gas exchange system was accurate to 1 ppm CO2. The shape factor used for black spruce was 4, in accordance with the BOREAS Experiment Plan, Appendix K, Version 3.0. Based on observations of two cross- sections of two needles per fascicle for five fascicles for six jack pine trees from Thompson, Manitoba, an average shape factor of 4.59 (+/- 0.07) was calculated. 4.2.1.1 Tolerance The acceptable range for net photosynthetic measurements is not available at this revision. 4.2.2 Frequency of Calibration The LI-COR LI-6200 was sent to the manufacturer for calibration and general maintenance in February 1994 before field work began (big mistake, see Section 10.1). The LI-6200 was examined daily for page parameters, operating parameters, and clock setting; quantum sensor calculation constant; CO2 analyzer calculation list; flow meter calculation list; relative humidity sensor calculation list; and analyzer reference. Each sensor was checked daily and periodically to make sure it was responding as expected: quantum sensor; air and leaf temperature match; IRGA temperature; flow meter; CO2 concentration; and relative humidity. The zero and SPAN for the CO2 analyzer were set daily. The flow meter was zeroed frequently. The LI-6250 CO2 gas analyzer was calibrated daily according to instrument specifications (CO2 levels), while system tests (e.g., leak tests, boundary layer resistance, soda lime test, and desiccant (k) test) were conducted periodically throughout each sampling day. Approximately every half hour, the desiccant tube was shaken. Daily, the chambers were cleaned and the batteries recharged. The foam pads in the chamber were changed after frequent usage and any noticeable damage. The optical image analysis system was calibrated according to instrument specifications each time the system was opened or after it was left for a period of time. A fine ruler and flat disks of known area were used in the calibration. The pressure chamber was inspected at the manufacturer's facility prior to field use. Safety checks were conducted from time to time throughout the sampling period. 4.2.3 Other Calibration Information During IFC-1, the LI-6200 system had problems caused by the manufacturer's calibration. For the days when this equipment problem occurred, the data could not be treated and thus will not be stored in the BOREAS Information System (BORIS). Furthermore, the radio handsets that were distributed to the field groups caused some failure in instrument functioning. Either the instrument completely shut down or the periodic calibrations detected the influence of the handsets. These data have been cleaned and removed from the data set available in BORIS. 5. Data Acquisition Methods Gas exchange and water potential measurements took place in five stands during daylight hours. Prior to each measurement period, instruments were calibrated and placed onsite (for example, on canopy access towers) for measurement. Five branches from randomly selected trees at a given canopy level were identified and prepared by exposing only a desirable amount of foliage for gas exchange measurement. Net photosynthesis was measured on these branches with a LI-COR LI- 6200 system. Ambient conditions were also obtained once or twice within the measurement period of the five samples. Once a canopy level was completed, another was started, which normally was within a half hour. Several cycles of measurement (upper and lower canopy) could be completed during a day. During the first IFC only, samples were harvested after four to five cycles and another five were selected. This was done to ensure that the measurement technique did not affect the sample by inducing high respiration rates from damaged tissue, for example. A branch (bearing leaves) section was placed into the cuvette for three 20- second measurements. This period varied in the first IFC, when investigators were trying to find an ideal measurement period for the species being measured. Three 30-second measurements, or three 60-second intervals, were found to be too long. Two 20- or 30-second intervals did not always provide enough data to determine whether data errors existed. The same branch section was measured periodically throughout the day (approximately once every hour). At the end of the day, these branch sections were harvested and stored in a freezer until leaf area was determined. The projected leaf areas of fresh aspen leaves that were harvested following the gas exchange measurements were measured using an optical image analysis system. Projected leaf area is essentially equivalent to half the area of the surface of the leaf (HASL) for flat leaves. Leaf area of each fresh conifer sample was measured using the volume displacement method as described in Appendix K of the BOREAS Experiment Plan (Version 3.0). Because precision work was required, the needles were removed from the shoot and the volume of the woody portion of the shoot was measured by submerging it in the liquid-filled container on the balance. The needle volume was the difference between the total volume and the woody volume. The length of all needles in the sample and the shoot silhouette were measured using the optical image analysis system. The shape factors for black spruce and jack pine respectively were 4.00 and 4.59. The silhouette area of conifer samples was measured by age class. (In the first IFC, however, there was only one age class.) A conifer shoot was first snipped/clipped into two age classes. These two age classes included (1) 1994 needles and (2) anything produced in 1993 and earlier. Each shoot section was then randomly thrown under the camera lens and a silhouette measurement was taken. These samples were then processed under the normal procedures for measuring leaf area (volume displacement). 6. Observations 6.1 Data Notes 6.2 Field Notes During IFC-1 only, canopy gas exchange measurements were made only in the upper canopy with the exception of 27-May in the YJP stand. On this particular day, gas exchange measurements were made on three branches per tree, for five trees for three canopy levels. (The data set will reflect this difference in numbering.) Water potential measurements were made on 1-Jun and for subsequent days. Identification errors have been corrected in the data set and are too detailed to list here. 7. Data Description 7.1 Spatial Characteristics 7.1.1 Spatial Coverage The data were collected from five principal sites in the NSA of Manitoba. The NSA is approximately 100 km wide by 80 km and is located 735 km north of Winnipeg. The principal sites in this study were: NSA-YJP flux tower site: Lat/Long: 55.89575 N, 98.28706 W UTM Zone 14, N:6194706.9 E:544583.9 NSA-OJP flux tower site: Lat/Long: 55.842 N, 98.62396 W UTM Zone 14, N:6198176.3 E:523496.2 NSA-OA canopy access tower site (auxiliary site number T2Q6A, BOREAS Experiment Plan, Version 3.0): Lat/Long: 55.88691 N, 98.67479 W UTM Zone 14, N: 6193540.7 E: 520342 NSA-OBS flux tower site: Lat/Long: 55.88007 N, 98.48139 W UTM Zone 14, N:6192853.4 E:532444.5 NSA-UBS canopy access tower site (auxiliary site number T6R5S, BOREAS Experiment Plan, Version 3.0): Lat/Long: 55.90802 N, 98.51865 W UTM Zone 14, N: 6195947 E:530092 Measurements were taken on the canopy access towers or, in the case of the YJP site, within 1 km of the flux tower. 7.1.2 Spatial Coverage Map Not available. 7.1.3 Spatial Resolution The data represent point source measurements made at the given locations. 7.1.4 Projection Not applicable. 7.1.5 Grid Description Not applicable. 7.2 Temporal Characteristics 7.2.1 Temporal Coverage Data acquisition took place during the three IFCs, which lasted from 24-May-1994 to 19-Sept-1994. 7.2.2 Temporal Coverage Map Not available. 7.2.3 Temporal Resolution During the first IFC, because of problems with the LI-6200, usable data were obtained only for four sampling days: YJP, 17-May; OJP, 30-May, and 01-June; and OBS, 05-Jun. During the second IFC, usable data were obtained for seven sampling days: YJP, August 1; OJP 27-Jul, 09-Aug; OASP, 29-Jul, 08-Aug; OBS, 05-Aug; and UBS, 03- Aug. During the third IFC, usable data were obtained for eight sampling days: YJP, 01- and 10-Sept; OJP, 31-Aug, 09-Sep; OASP, 03-Sept and 16-Sept; OBS, 07-Sept; and UBS, 17-Sep. 7.3 Data Characteristics Data characteristics are defined in the companion data file (te09gxda.def). 7.4 Sample Data Record Sample data format shown in the companion data definition file (te09gxda.def). 8. Data Organization 8.1 Data Granularity All of the In Situ Diurnal Gas Exchange of NSA Boreal Forest Stands Data are contained in one dataset. 8.2 Data Format(s) The data files contain numerical and character fields of varying length separated by commas. The character fields are enclosed with a single apostrophe marks. There are no spaces between the fields. Sample data records are shown in the companion data definition files (te09gxda.def). 9. Data Manipulations 9.1 Formulae During the data processing, the following formulae were used: a) water use efficiency (WUE)=(photosynthesis (µmol m-2 s-1) /transpiration(mmol m-2 s-1)) b) mesophyll conductance (GM)=( (photosynthesis (µmol m-2 s-1) /Intercellular CO2 concentration (ppm)) x 1000) (Fites and Teskey, 1988. Can. J. For. Res. 18:150-157). c) Ci/Ca: CINT: Intercellular CO2 concentration (ppm) / CO2 concentration (ppm)) 9.1.1 Derivation Techniques and Algorithms None at this time. 9.2 Data Processing Sequence 9.2.1 Processing Steps Data were stored in the LI-6200 system during the measurement day. Data were then downloaded/transferred from the system to an IBM or IBM compatible computer. When the true leaf areas for each sample were available, these values were entered into the LICOR programming software, and all gas exchange parameters subsequently were recomputed. Raw data for each day of data were printed and examined for anomalies in each line of data. Subsequently any data corresponding to each line of data that showed an anomaly were removed. For example, a branch was normally placed in the cuvette for three repetitions of 20 seconds. If in one (or more) of these repetitions, a parameter output was more than 25% out of range, then the entire line of data was removed, leaving only the data corresponding to the 'clean' repetitions. Data were recomputed using the LI-COR software if any other errors in default parameters were detected. For example, on occasion, the ratio of the stomatal conductance of one side of the leaf to the other (STMRAT) was erroneously entered in the field. Using Excel (Version 5.0 for IBM), a program was written to process each cleaned data set. This program did the following: 1) Calculated new parameters that were not part of the LI-COR software system. These parameters included water use efficiency, mesophyll conductance, and Ci:Ca ratios. 2) Permitted the user to average the data depending on whether the data had been recomputed or not. 3) Permitted the user to average the data depending on whether there were two or three repetitions of data, taking into account missing data. 4) Formatted the data into column format. Once the data were in a cleaned, column format, water potential values for each time period were entered into the data set. Data in imperial units were converted to standard metric units. 9.2.2 Processing Changes See Section 9.2.1. 9.3 Calculations During the data processing, the following formulae were used: a) water use efficiency (WUE)=(photosynthesis (µmol m-2 s-1) /transpiration(µmol m-2 s-1)) b) mesophyll conductance (GM)=( (photosynthesis (µmol m-2 s-1) /Intercellular CO2 concentration (ppm)) x 1000 ) (Fites and Teskey, 1988. Can. J. For. Res. 18:150-157). c) Ci/Ca: CINT: Intercellular CO2 concentration (ppm) / CO2 concentration (ppm) 9.3.1 Special Corrections/Adjustments Raw data for each day of data were printed and examined for anomalies in each line of data. Subsequently, any data corresponding to each line of data that showed an anomaly were removed. For example, a branch was normally placed in the cuvette for three repetitions of 20 seconds. If in one (or more) of these repetitions, a parameter output was more than 25% out of range, then the entire line of data was removed, leaving only the data corresponding to the 'clean' repetitions. Data were recomputed using the LI-COR software if any other errors in default parameters were detected. For example, on occasion, the ratio of the stomatal conductance of one side of the leaf to the other (STMRAT) was erroneously entered in the field. Using the software Excel (Version 5.0 for IBM), a program was written to process each cleaned data set. This program did the following: 1) Calculated new parameters that were not part of the LI-COR software system. These parameters included water use efficiency, mesophyll conductance, and Ci:Ca ratios. 2) Permitted the user to average the data depending on whether the data had been recomputed or not. 3) Permitted the user to average the data depending on whether there were two or three repetitions of data, taking into account missing data. 4) Formatted the data into column format. Once the data were in a cleaned, column format, water potential values for each time period were entered into the data set. Data in imperial units were converted to standard metric units. 9.3.2 Calculated Variables water use efficiency (WUE) mesophyll conductance (GM) intercellular CO2 concentration(ppm) 9.4 Graphs and Plots None submitted. 10. Errors 10.1 Sources of Error During IFC-1, the LI-6200 system had problems caused by the manufacturer's calibration. For days when this equipment problem occurred, the data could not be treated and thus will not be stored in BORIS. Furthermore, the radio handsets that were distributed to the field groups caused some failure in instrument functioning. Either the instrument completely shut down or the periodic calibrations detected the handset influence. These data have been cleaned and removed from the data set available in BORIS. All erroneous default parameters were adjusted. Anomalies in each line of data were removed. For example, a branch was normally placed in the cuvette for three repetitions of 20 seconds. If in one (or more) of these repetitions, a parameter output was more than 25% out of range, then the entire line of data was removed, leaving only the data corresponding to the 'clean' repetitions. Most often these anomalies could not be explained. However, a sudden burst in light during the measurement or a poor electrical signal could cause these kinds of errors. These out-of-range errors were detected and removed. See Section 9.2.1. for additional details. 10.2 Quality Assessment 10.2.1 Data Validation by Source All known errors were removed. 10.2.2 Confidence Level/Accuracy Judgment All known errors were removed, yielding a high degree of confidence in this data set. 10.2.3 Measurement Error for Parameters No measurement errors are known at this time 10.2.4 Additional Quality Assessments Data were compared to results observed in the laboratory, and results are within a realistic range. 10.2.5 Data Verification by Data Center Data was examined for general consistency and clarity. 11. Notes 11.1 Limitations of the Data None given. 11.2 Known Problems with the Data All known problems have been removed; see Section 10.1. 11.3 Usage Guidance Use data columns as presented. 11.4 Other Relevant Information Not available at this time. 12. Application of the Data Set These data can be used to characterize the diurnal water potential curves for these sites to obtain an indication to what extent soil moisture supply to leaves might be limiting photosynthesis. 13. Future Modifications and Plans This is the final version of data. 14. Software 14.1 Software Description None given. 14.2 Software Access None given. 15. Data Access 15.1 Contact Information Ms. Beth Nelson BOREAS Data Manager NASA GSFC Greenbelt, MD (301) 286-4005 (301) 286-0239 (fax) beth@ltpmail.gsfc.nasa.gov 15.2 Data Center Identification See Section 15.1. 15.3 Procedures for Obtaining Data Users may place requests by telephone, electronic mail, or fax. Discussions with either Marie Coyea or Hank Margolis before using this data are essential. 15.4 Data Center Status/Plans The TE-09 gas exchange data are available from the Earth Observing System Data and Information System (EOSDIS), Oak Ridge National Laboratory (ORNL), Distributed Active Archive Center (DAAC). The BOREAS contact at ORNL is: ORNL DAAC User Services Oak Ridge National Laboratory (865) 241-3952 ornldaac@ornl.gov ornl@eos.nasa.gov 16. Output Products and Availability 16.1 Tape Products None. 16.2 Film Products None. 16.3 Other Products Tabular ASCII files. 17. References Fites, J.A. and R. O. Teskey. 1988. CO2 and water vapour exchange of Pinus in relation to stomatal behavior: test of an optimization hypothesis. Can. J. For. Res. 18:150-157 17.1 Platform/Sensor/Instrument/Data Processing Documentation Decagon Devices Inc. 1990 AgVision monochrochrom system, root and leaf analysis, operators manual. Pullman, WA. LI-COR,Inc. 1990. LI-COR 6200 Condensed Reference. Software Revision 2.00 (August 1990). Lincoln, NE. LI-COR, Inc. 1990. The LI-COR 6200 Primer: An introduction to operating the LI- 6200 portable photosynthesis system. (May 1990) Lincoln, NE. LI-COR, Inc. 1990. LI-COR 6200 Technical reference. (March 1990). Lincoln, NE. LI-COR, Inc. 1993. LI-COR 6200 software. Lincoln, NE. 17.2 Journal Articles and Study Reports Coyea, M.R., Q-L. Dang, H. Margolis, M. Sy, and G. J. Collatz. 1996. Canopy profiles of PAR, nitrogen, and photosynthetic capacity:implications for scaling from leaf to canopy. North American Forest Biology Workshop. June 16-20 1996. Poster presented. Dang, Q-L., H. Margolis, M.R. Coyea, M. Sy, G.J. Collatz and De Yue. 1995. Environmental controls on photosynthesis and stomatal conductance of boreal forest tree species. Ecological Society of America. July 31-August 4, 1995. Snowbird, UT. Dang, Q-L., H. Margolis, M. Sy, M.R. Coyea, and G. J. Collatz. 1996. Profiles of photosynthetically active radiation, nitrogen, and photosynthetic capacity in the boreal forest: implications for scaling from leaf to canopy. Ecological Society of America. August 10-14, 1996. Providence RI. Dang, Q-L., H. Margolis, M. Sy, M.R. Coyea, and G.J. Collatz. 1996. Water potential and vapor pressure difference as environmental controls on branch- level gas exchange of boreal tree species in northern Manitoba. North American Forest Biology Workshop. June 16-20, 1996. Dang, Q.L., H. Margolis, M.R. Coyea, M. Sy, and G. J. Collatz,. 1996. Regulation of branch-level gas exchange of boreal trees: role of shoot water potential and vapor pressure difference. Tree Phys. In press. Dang, Q.L., H. Margolis, M. Sy, M.R. Coyea, G.J. Collatz, and C. L. Walthall. 1996. Profiles of PAR, nitrogen, and photosynthetic capacity in the boreal forest: Implications for scaling from leaf to canopy. J. of Geophys. Res. In press. Sellers, P., and F. Hall. 1994. Boreal Ecosystem-Atmosphere Study: Experiment Plan. Version 1994-3.0, NASA BOREAS Report (EXPLAN 94). Sellers, P., and F. Hall. 1996. Boreal Ecosystem-Atmosphere Study: Experiment Plan. Version 1996-2.0, NASA BOREAS Report (EXPLAN 96). Sellers, P., and F. Hall. 1997. BOREAS Overview Paper. JGR Special Issue (in press). Sellers, P., F. Hall, and K.F. Huemmrich. 1996. Boreal Ecosystem-Atmosphere Study: 1994 Operations. NASA BOREAS Report (OPS DOC 94). Sellers, P., F. Hall, and K.F. Huemmrich. 1997. Boreal Ecosystem-Atmosphere Study: 1996 Operations. NASA BOREAS Report (OPS DOC 96). Sellers, P., F. Hall, H. Margolis, B. Kelly, D. Baldocchi, G. den Hartog, J. Cihlar, M.G. Ryan, B. Goodison, P. Crill, K.J. Ranson, D. Lettenmaier, and D.E. Wickland. 1995. The boreal ecosystem-atmosphere study (BOREAS): an overview and early results from the 1994 field year. Bulletin of the American Meteorological Society. 76(9):1549-1577. 17.3 Archive/DBMS Usage Documentation None. 18. Glossary of Terms None. 19. List of Acronyms BOREAS - BOReal Ecosystem-Atmosphere Study BORIS - BOREAS Information System DAAC - Distributed Active Archive Center EOS - Earth Observing System EOSDIS - EOS Data and Information System FPAR - Fraction of PAR GSFC - Goddard Space Flight Center HASL - Half the Area of the Surface of the Leaf IFC - Intensive Field Campaign IRGA - Infrared Gas Analyzer NASA - National Aeronautics and Space Administration NSA - Northern Study Area OA - Old Aspen OBS - Old Black Spruce OJP - Old Jack Pine PANP - Prince Albert National Park PAR - Photosynthetically Active Radiation PI - Principal Investigator Ps - Photosynthesis ORNL - Oak Ridge National Laboratory UBS - Upland Black Spruce URL - Uniform Resource Locator VPD - Vapor Pressure Deficit YA - Young Aspen YJP - Young Jack Pine 20. Document Information 20.1 Document Revision Date Written: 27-Feb-1997 Last Updated: 08-May-1998 20.2 Document Review Date(s) BORIS Review: 26-Feb-1998 Science Review:06-Feb-1998 20.3 Document ID 20.4 Citation The diurnal gas exchange and water potential measurements were collected for BOREAS by the TE-09 research team from Universite Laval, Quebec, Canada, under the direction of H. Margolis. The dedicated efforts of Marie R. Coyea, Mikailou Sy, Raynald Paquin, Simon Arbour, Munyonge Abwe Wa Masabo, and Tshinkenke Vinlha in collecting and preparing these data is particularly appreciated. 20.5 Document Curator 20.6 Document URL WATER POTENTIAL PHOTOSYNTHETIC RATE STOMATAL CONDUCT H20 STOMATAL CONDUCT CO2 INTERCELLULAR CO2 CONCENTRATION TRANSPIRATION RATE WATER USE EFFICIENCY MESOPHYL CONDUCTANCE INTERCELLULAR CO2 RATIO PPFD CO2 CONCENTRATION LEAF AREA LEAF BOUND LAYER CONDUCTANCE STOMATAL CONDUCTANCE TE09_Gas_Exchange Page 18 of 1 05/26/98