BOREAS TE-09 NSA Photosynthetic Capacity and Foliage Nitrogen Data Summary The BOREAS TE-09 team collected several data sets related to chemical and photosynthetic properties of leaves in boreal forest tree species. This data set describes the spatial and temporal relationship between foliage nitrogen concentration and photosynthetic capacity in the canopies of black spruce, jack pine, and aspen. The data were collected from June to September 1994 and are useful for modeling the vertical distribution of carbon fixation for different forest types in the boreal forest. The data are available 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 This data set describes the relationship between foliage nitrogen concentration and photosynthetic capacity in the canopies of the BOReal Ecosystem Atmosphere Study (BOREAS) Northern Study Area (NSA)-Old Black Spruce (OBS), NSA-Upland Black Spruce (UBS), NSA-Old Jack Pine (OJP), NSA-Young Jack Pine (YJP) and NSA- Old Aspen (OA). 1.1 Data Set Identification BOREAS TE-09 NSA Photosynthetic Capacity and Foliage Nitrogen Data 1.2 Data Set Introduction The canopy profiles of nitrogen concentration and photosynthetic capacity were examined as part of an effort to characterize the spatial and temporal variations in photosynthetic capacity and nitrogen allocation in the boreal forest. This information will be useful for modeling the vertical distribution of carbon fixation for different forest types in the boreal forest. Samples were taken from five forest types in the NSA: NSA-OBS, NSA-UBS, NSA-OJP, NSA-YJP, and NSA-OA during each of the three Intensive Field Campaigns (IFCs) in 1994. Measurements were taken under controlled environmental conditions in the laboratory. An open gas exchange system in differential mode was used for measuring the photosynthetic capacity. 1.3 Objective/Purpose This data set was collected and prepared to provide the profile of photosynthetic capacity and nitrogen concentration in the forest canopy of NSA- OBS (Picea mariana Mill.), NSA-UBS, NSA-OJP (Pinus banksiana Lamb.), NSA-YJP, and NSA-OA (Populus tremuloides Michx.). This information will also be useful for modeling the vertical distribution of carbon fixation for different forest types in the boreal forest. 1.4 Summary of Parameters Light-saturated net photosynthesis, nitrogen concentration. 1.5 Discussion The canopy profiles of nitrogen concentration and photosynthetic capacity were examined as part of an effort to characterize the spatial and temporal variations in photosynthetic capacity and nitrogen allocation in the boreal forest. This information will be useful for modeling the vertical distribution of carbon fixation for different forest types in the boreal forest. Samples were taken from five forest types in the NSA: NSA-OBS, NSA-UBS, NSA-OJP, NSA-YJP, and NSA-OA during each of the three IFCs in 1994. Measurements were taken under controlled environmental conditions in the laboratory. An open gas exchange system in differential mode was used for measuring the photosynthetic capacity. 1.6 Related Data Sets BOREAS TE-09 Photosynthetic Response Data 2. Investigator(s) 2.1 Investigator(s) Name and Title Dr. Hank Margolis, Associate Professor 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 Contact 1 --------------- Dr. Hank Margolis Universite Laval Faculte de foresterie et de geomatique Pavillon Abitibi-Price Sainte-Foy, Quebec Canada (418) 656-7120 Hank.margolis @sbf.ulaval.ca Contact 2 --------------- Dr. Qinglai Dang Lakehead University Faculty of Forestry Thunder Bay Canada (807) 343-8507 (807) 343-8116 (fax) E-mail: Qinglai.Dang@flash.lakeheadu.ca Contact 3 --------------- Shelaine Curd NASA GSFC Greenbelt, MD (301) 286-2447 (301) 286-0239 (fax) shelaine.curd@gsfc.nasa.gov 3. Theory of Measurements During the process of photosynthesis, CO2 is assimilated by the green leaves while H2O is released into the atmosphere. The amount of water released and the amount of CO2 absorbed are determined by comparing the concentrations of water vapor and CO2 in the air moving into the leaf cuvette and those in the air moving out of the cuvette at a certain flow rate. The concentration of CO2 and water vapor in both incoming and outgoing air streams is measured using an infrared gas analyzer (IRGA). The total nitrogen concentration of foliage was determined by the Kjeldahl method. This consists of two main steps: (1) The nitrogen in the sample is converted to NH4+ by digestion with concentrated H2SO4 containing substances that promote this conversion. (2) The NH4+ is determined from the amount of NH3 liberated by distillation of the digest with alkali. This is a common procedure for total nitrogen determination for plant materials. 4. Equipment 4.1 Sensor/Instrument Description 4.1.1 Collection Environment The vertical profile of the canopy was divided into three layers; top, middle, and bottom. For OBS, UBS, and OJP, all three layers were of the same species. For YJP, the bottom layer was the understory black spruce seedlings, while the top and middle layers were jack pine. For OA, the bottom layer was alder, while the top and middle layers were aspen. Branch samples were harvested from each layer and were immediately recut under water. The samples were then transported back to the laboratory for gas exchange measurements. The cut surface of the branch was submerged in water during transport and in the laboratory. Samples were cut in the dark. The samples that were about to be measured, however, were exposed to saturated light for 2 hours prior to measurement to induce stomatal opening and photosynthetic activity. To keep a continual supply of water to the branch, the cut surface was kept in contact with water during the entire period. The light source was two 1,000-watt high-pressure sodium lamps. Different levels of light were achieved by using different neutral density filters. The environmental conditions inside the leaf cuvette were as follows: temperature 20 +/- 0.5 C; vapor pressure deficit 0.7 +/- 0.2 kPa; CO2 360 +/- 20 ppm. Photosynthesis and related parameters all are expressed on a hemisurface area basis. The shape factors for the leaf area calculation were 4 and 4.59, respectively, for black spruce and jack pine. 4.1.2 Source/Platform Branch samples were taken using a shotgun and were recut under water. Photosynthesis was measured in the laboratory under a controlled environment. 4.1.3 Source/Platform Mission Objectives 1. To obtain the canopy profile of photosynthetic capacity and nitrogen concentration. 2. To examine interspecific and interseasonal differences in these canopy profiles. 4.1.4 Key Variables Rate of light-saturated net photosynthesis, foliar nitrogen concentration. 4.1.5 Principles of Operation A LI-COR-6262 IRGA, thermocouples, balance, Decagon AgVision root and leaf analysis system, and LI-COR quantum Photosynthetically Active Radiation (PAR) sensor were used in the data collection process. Eight samples were measured from each canopy level. Two samples were measured at a time, and measurements were alternated between different canopy levels. 4.1.6 Sensor/Instrument Measurement Geometry All samples were taken from the upper third of the forest canopy. Efforts were made to keep the amount of foliage relatively consistent from sample to sample. The leaf chamber for the measurement is about 1,300 in. 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 Leaf area measurement system/optical image analysis system (AgVision, monochrome system, root and leaf analysis) Decagon Devices, Inc. P.O. Box 835 Pullman, WA 99163 (800) 755-2751 4.2 Calibration The gas analyzer was calibrated against standard gas that was calibrated against the prime CO2 standard in the NSA lab in Thompson. Calibration was done at the beginning of each field campaign. 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 No tolerance level was set for these measurements. 4.2.2 Frequency of Calibration LI-COR 6262 IRGA was calibrated at the beginning of each IFC. 4.2.3 Other Calibration Information None. 5. Data Acquisition Methods The vertical profile of the canopy was divided into three layers: top, middle, and bottom. For OBS, UBS, and OJP, all three layers were of the same species. For YJP, the bottom layer was the understory black spruce seedlings,while the top and middle layers were jack pine. For OA, the bottom-layer was alder, while the top and middle layers were aspen. Branch sampleswere harvested from each layer and were immediately recut under water. The samples were then transported back to the laboratory for gas exchange measurements. The cut surface of the branch was submerged in water during transport and in the laboratory. Samples were cut in the dark. The samples that were about to be measured, however, were exposed to saturated light for 2 hours prior to measurement to induce stomatal opening and photosynthetic activity. To keep a continual supply of water to the branch, the cut surface was in contact with water during the entire period. The light source was two 1,000-watt high-pressure sodium lamps. Different levels of light were achieved by using different neutral density filters. The environmental conditions inside the leaf cuvette were as follows: temperature 20 +/- 0.5 8C; vapor pressure deficit 0.7 +/- 0.2 kPa; CO2 360 +/- 20 ppm. Photosynthesis and related parameters all are expressed on a hemisurface area basis. The shape factors for the leaf area calculation were 4 and 4.59, respectively, for black spruce and jack pine. 6. Observations 6.1 Data Notes None. 6.2 Field Notes Samples were taken between 6:00 and 7:00 a.m. from one site per day over 5 days. See pages 2-23 and 2-24 in the BOREAS Experiment Plan, Version 3.0, for a description of site conditions. 7. Data Description 7.1 Spatial Characteristics 7.1.1 Spatial Coverage At each site, branch samples were taken from four different trees that were at least 10 m apart from one another. The location of each site is as follows: 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, -8.62396 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): 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): Lat/Long: 55.90802 N, 98.51865 W UTM Zone 14, N: 6195947, E: 530092 7.1.2 Spatial Coverage Map Not available. 7.1.3 Spatial Resolution The data represent point source measurements made near the designated sites. 7.1.4 Projection Not applicable. 7.1.5 Grid Description Not applicable. 7.2 Temporal Characteristics 7.2.1 Temporal Coverage The data were collected during the period of 02-June to 04-September-1994. Samples were taken between 6:00 and 7:00 A.M. Measurements in the lab normally took 8 to 14 hours. An independent data set was taken during each of the three IFCs in 1994. 7.2.2 Temporal Coverage Map Site Sample Dates (1994) ------- ---------------------- NSA-OBS 09-Jun, 21-Jul, 04-Sep NSA-UBS 06-Jun, 22-Jul, 01-Sep NSA-OJP 02-Jun, 19-Jul, 31-Aug NSA-YJP 05-Jun, 23-Jul, 02-Sep NSA-OASP 07-Jun, 21-Jul, 03-Sep 7.2.3 Temporal Resolution Each of the sites was visited three times during 1994. 7.3 Data Characteristics Data characteristics are defined in the companion data definition file (te09npd.def). 7.4 Sample Data Record Sample data format shown in the companion data definition file (te09npd.def). 8. Data Organization 8.1 Data Granularity All of the Photosynthetic Capacity and Foliage Nitrogen Data are contained in one dataset. 8.2 Data Format 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 (te09npd.def). 9. Data Manipulations 9.1 Formulae 9.1.1 Derivation Techniques and Algorithms Photosynthetic capacity was calculated according to von Caemmerer and Farquhar (1981), Planta 153: 376-387. 9.2 Data Processing Sequence 9.2.1 Processing Steps Data were recorded automatically by a computer and also printed on a printer. Subsequent calculations of different parameters were performed using MS Excel for Windows 5.0. BORIS staff processed the data by: 1) Reviewing the initial data files and loading them online for BOREAS team access. 2) Designing relational data base tables to inventory and store the data. 3) Loading the data into the relational data base tables. 4) Working with the Hydrology (HYD)-06 team to document the data set. 5) Extracting the standardized data into logical files. 9.2.2 Processing Changes None. 9.3 Calculations Photosynthetic capacity was calculated according to von Caemmerer and Farquhar (1981), Planta 153: 376-387. 9.3.1 Special Corrections/Adjustments None. 9.3.2 Calculated Variables Photosynthetic capacity was calculated according to von Caemmerer and Farquhar (1981) Planta 153: 376-387. 9.4 Graphs and Plots Photosynthetic capacity versus N. 10. Errors 10.1 Sources of Error None. 10.2 Quality Assessment Data are preliminary. Please contact Hank Margolis or Qinglai Dang if the data are used for publication. (See Section 2.3 contact information). 10.2.1 Data Validation by Source A base measurement (i.e., when the cuvette contains no samples) was taken both before and after each set of measurements. Other measurements were adjusted by the base values, if necessary. 10.2.2 Confidence Level/Accuracy Judgment No statistical confidence level is available, but BORIS staff feels that these data are reliable. 10.2.3 Measurement Error for Parameters None. 10.2.4 Additional Quality Assessments Calculated results were plotted and the patterns were examined and compared with the literature. Outliers (determined visually) were eliminated from the data set. 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. 11.2 Known Problems with the Data None. 11.3 Usage Guidance None. 11.4 Other Relevant Information None. 12. Application of the Data Set This data set was collected and prepared to provide the profile of photosynthetic capacity and nitrogen concentration in black spruce, jack pine, and aspen stands. This information will also be useful to modeling the vertical distribution of carbon fixation for different forest types in the boreal forest. 13. Future Modifications and Plans None. 14. Software 14.1 Software Description Calculations were performed using MS Excel for Windows 5.0. 14.2 Software Access Contact Microsoft Corp. 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. 15.4 Data Center Status/Plans The TE-09 photosynthesis and nitrogen 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 17.1 Platform/Sensor/Instrument/Data Processing Documentation Li-cor 6262 Infrared gas analyzer manual. 17.2 Journal Articles and Study Reports Bremner, J.M. and C.S. Mulvaney, 1982. Nitrogen - Total. pp. 595-623. In: Methods of Soil Analysis, Part 2. Chemical and Microbiological Properties. Second edition. A.L. Page, R.H. Miller and D.R. Keeney, editors. American Society of Agronomy Inc. and the Soil Science Society of America Inc., Madison, WI. Dang, Q.L., H. Margolis, M.R. Coyea, M. Sy, G.J. Collatz, and C. Walthall. 1997. Profiles of photosynthetically active radiation, nitrogen, and photosynthetic capacity in the boreal forest: implications for scaling from leaf to canopy. J. Geophys. Res., BOREAS Special Issue (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, andK.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. von Caemmerer, S. and G.D. Farquhar, 1981. Some relationships between biochemistry of photosynthesis and the gas exchange of leaves. Planta 153:376-387. 17.3 Archive/DBMS Usage Documentation None. 18. Glossary of Terms A - Photosynthetic capacity (umol/m2/s) N% - percent nitrogen concentration (%) N g/m2 -nitrogen per unit hemisurface area (g/m2) N mg/g -nitrogen per dry mass of foliage (mg/g) 19. List of Acronyms ASCII - American Standard Code for Information Interchange BOREAS - BOReal Ecosystem-Atmosphere Study BORIS - BOREAS Information System CGR - Certified by Group CPI - Checked by Pricipal Investigator CPI-??? - CPI but questionable DAAC - Distributed Active Archive Center EOS - Earth Observing System EOSDIS - EOS Data and Information System GSFC - Goddard Space Flight Center HYD - Hydrology 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 ORNL - Oak Ridge National Laboratory PANP - Prince Albert National Park PAR - Photosynthetically Active Radiation SSA - Southern Study Area TE - Terrestrial Ecology UBS - Upland Black Spruce URL - Uniform Resource Locator YJP - Young Jack Pine 20. Document Information 20.1 Document Revision Dates Written: 3-Dec-1996 Last updated: 19-Mar-1998 20.2 Document Review Dates BORIS Review: 21-Apr-1997 Science Review: 5-Nov-1997 20.3 Document ID 20.4 Citation Please contact one of the individuals listed in section 2.3 Contact Information. 20.5 Document Curator 20.6 Document URL Keywords PHOTOSYNTHETIC RESPONSE NITROGEN STOMATAL CONDUCTANCE TE09_NITROGEN_PHOTO.doc Page 13 of 13 04/17/98