BOREAS TE-04 Branch Bag Data from Boreal Tree Species

Summary

The BOREAS TE-04 team collected continuous records of gas exchange under
ambient conditions from intact boreal forest trees in the BOREAS NSA
from 23-Jul-1996 until 14-Aug-1996. These measurements can be used to
test models of photosynthesis, stomatal conductance, and leaf
respiration, such as SiB2 (Sellers et al., 1996) or the leaf model
(Collatz et al., 1991), and programs can be obtained from the
investigators.

Table of Contents

1 Data Set Overview

2 Investigators

3 Theory of Measurements

4 Equipment

5 Data Acquisition Methods

5 Observations

7 Data Description

8 Data Organization

9 Data Manipulations

10 Errors

11 Notes

12 Application of the Data Set

13 Future Modification 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-04 Branch Bag Data from Boreal Tree Species

1.2 Data Set Introduction

These data are summaries of steady-state gas exchange measurements
conducted under field conditions from 23-Jul-1996 until 14-Aug-1996 in
the BOReal Ecosystem-Atmosphere Study (BOREAS).

1.3 Objective/Purpose

These studies were conducted to provide a basis for calibrating models
of stomatal conductance, photosynthesis, and respiration used in
simulating boreal ecosystem-atmosphere interactions.

1.4 Summary of Parameters

The parameters provided in each data set are intended to provide a
sufficient description of the micro-environment of the leaf to permit
the observations to be used for model validation. A complete list of the
parameters is given in Section 4.1.1. The key measurements are the rates
of net CO~2~ exchange, the rate of evaporation of water from the leaf,
the stomatal conductance to water vapor, and the intercellular CO~2~
concentration.

1.5 Discussion

The branch bag (described in Section 4.1) was installed at the top of
the canopy with an attached tree crown inside. The bag was connected to
an MPH-1000 steady-state gas exchange system. A heat exchanger was used
to eliminate the difference between bag air temperature and ambient
temperature; thus, the conditions inside the bag were very close to
those outside. The measurements were made in a short interval (about 5
min) and could be used to check the photosynthesis model and the
stomatal model. Parameters from fitting leaf model to leaf gas exchange
data have been used to simulate these data. The simulation is still
ongoing. Tree species measured were black spruce (Picea mariana) at the
Old Black Spruce (OBS) site in the NSA and jack pine (Pinus banksiana)
at the Old Jack Pine (OJP) site and the Young Jack Pine (YJP) site in
the NSA.

1.6 Related Data Sets

BOREAS TE-02 Foliage Respiration Data

BOREAS TE-04 Gas Exchange Data from Boreal Tree Species

BOREAS TE-05 Leaf Gas Exchange Data

BOREAS TE-05 Surface Meteorological and Radiation Data

BOREAS TE-09 In Situ Diurnal Gas Exchange of NSA Boreal Forest Stands

BOREAS TF-03 NSA-OBS Tower Flux, Meteorological, and Soil Temperature
Data

2\. Investigators

2.1 Investigators Name and Title

Dr. Joseph A. Berry

Dr. John Gamon

Dr. Wei Fu

Dr. Art Fredeen

2.2 Title of Investigation

Measurement and Prediction of CO~2~ and H~2~O Exchange from Boreal
Forest Tree Species

2.3 Contact Information

[Contact 1:]{.underline}

Dr. Joseph A. Berry

Department of Plant Biology

Carnegie Institution of Washington

Stanford, CA

\(415\) 325-1521 ext 221

\(415\) 325-6857 (fax)

joeberry@biosphere.stanford.edu

[Contact 2:]{.underline}

Andrea Papagno

Raytheon ITSS

NASA GSFC

Greenbelt, MD

\(301\) 286-3134

\(301\) 286-0239 (fax)

Andrea.Papagno@gsfc.nasa.gov

3\. Theory of Measurements

The measurements reported here were made by generally accepted
procedures for laboratory gas exchange. Branches were enclosed in a
branch bag that was set up to trace ambient environmental conditions.
Net exchange of CO~2~ and H~2~O was determined by infrared gas analysis
of the air flowing through the stirred cuvette.

4\. Equipment

4.1 Sensor/Instrument

Branch Bag (cylindrical openflow transparent bag, diameter 0.8 m, length
1 m)

Gas Exchange System (Model MPH-1000; Campbell Scientific, Logan UT)

Infrared Gas Analyzer (IRGA) (Model 6262; LICOR Inc., Lincoln, NB)

Dew Point Mirror (Model Dew-10; General Eastern, Woburn, MA)

4.1.1 Collection Environment

All experiments were conducted with intact attached crowns of trees (top
0.9 m) in the NSA of BOREAS. For specific weather conditions on
experiment days, see meteorological data files.

4.1.2 Source/Platform

Branch bags were suspended from the canopy access towers. Other
equipment was on the same towers.

4.1.3 Source/Platform Mission Objectives

The experiments were conducted to validate models of photosynthesis,
stomatal regulation, and respiration at an intermediate level.

4.1.4 Key Variables

P0 atmospheric pressure (Pa)

rbw boundary layer resistance (m^2^ s/mol)

ea ambient water vapor pressure (Pa)

Ca ambient CO~2~ concentration (μmol/mol)

Ta ambient temperature (°C)

PFD flux density of PAR (μmol/m^2^s)

SW short wave radiation (W/m^2^)

LW long wave radiation (W/m^2^)

Tl leaf temperature (°C)

Cs CO~2~ concentration at leaf surface (μmol/mol)

Hs relative humidity at leaf surface (%)

Ci CO~2~ concentration in intercellular air spaces (μmol/mol)

Pn net photosynthetic rate (μmol/m^2^s)

Gsw stomatal conductance (mol/m^2^ s)

E transpiration rate (mmol/m^2^ s)

4.1.5 Principles of Operation

Temperature, CO~2~ concentration, and H~2~O vapor pressure were
determined with appropriate sensors. Net CO~2~ and H~2~O exchange was
determined by mass balance analysis of the air flowing through the
cuvette. Gas exchange parameters, Ci, and Gsw were calculated. The
hemisurface leaf area used in these measurements was 1.0 to 3.9 m^2^ on
a given tree. The projected area of the crown was estimated by analysis
photographs.

4.1.6 Sensor Instrument Measurement Geometry

Leaves/needles were enclosed in a cuvette. All measurements are
expressed on a leaf area basis; for the conifers, this is reported as
the hemisurface area of the needles (half of the total surface area) as
determined by fresh weight calibrated to volume displacement (J. Norman,
personal communication).

4.1.7 Manufacturer of Sensor/Instrument

Gas exchange system (Model MPH-1000; Campbell Scientific, Logan, UT)

IRGA (Model 6262; LICOR Inc., Lincoln, NE)

Dew Point Mirror (Model Dew-10; General Eastern, Woburn, MA)

4.2 Calibration

CO~2~ concentration was referenced to standard CO~2~ tanks provided by
BOREAS; H~2~O vapor was referenced to a dew point mirror instrument; air
flow was calibrated by volume displacement; photosynthetically active
radiation (PAR) flux was referenced to a LICOR quantum probe.

4.2.1 Specifications

There are no published specifications for the complete system of
instruments used in this study.

4.2.1.1 Tolerance

All calibrations are better than +/- 1%.

4.2.2 Frequency of Calibration

Calibration and instrument zeros were checked daily. Checks against the
BOREAS gas standards was made every week or two.

4.2.3 Other Calibration Information

No significant adjustments or drift of calibration occurred over the
interval of these measurements.

5\. Data Acquisition Methods

In each branch bag experiment, only flow rate was controlled. A plastic
bag buffered air flow and gave stable CO~2~ supply. A heat exchanger was
used to eliminate the temperature differences between bag air and
ambient air. Conditions in the branch bag tracked those of the ambient.
The hemisurface leaf area used in these measurements was 1.0 to 3.9 m^2^
on a given tree. The projected area of the crown was estimated by
analysis photographs.

6\. Observations

6.1 Data Notes

These experiments were conducted from 23-Jul-1996 until 14-Aug-1996,
spending a few consecutive days at each site. The studies were conducted
with the top 0.8-0.9 m of a single crown at each site. We believe that
these measurements are representative of the trees at the site, but it
was not possible to obtain a statistically representative sample.
Measurements conducted with a LICOR 6400 photosynthesis system on
needles from an adjacent tree can be used to determine the
photosynthetic capacities at these sites.

6.2 Field Notes

None given.

7\. Data Description

7.1 Spatial Characteristics

7.1.1 Spatial Coverage

The NSA measurement sites and associated North American Datum of 1983
(NAD83) coordinates are:

OBS, site id T3R8T, Lat/Long: 55.88007°N, 98.48139°W, Universal
Transverse Mercator (UTM) Zone 14, N: 6,192,853.4, E: 532,444.5.

OJP, site id T7Q8T, Lat/Long: 55.92842°N, 98.62396°W, UTM Zone 14, N:
6,198,176.3, E: 523,496.2.

YJP, site id T8S9T, Lat/Long: 55.89575°N, 98.28706°W, UTM Zone 14, N:
6,194,706.9, E: 544,583.9.

7.1.3 Spatial Resolution

These data are point measurements taken from trees near the given
locations.

7.1.4 Projection

Not applicable.

7.1.5 Grid Description

Not applicable.

7.2 Temporal Characteristics

These measurements were coupled with the ambient environment. There is
direct correspondence between the temperature, light intensity, or other
environmental conditions in the branch bag during these experiments and
the ambient environmental conditions at the site of the measurements.
However, air temperature in the bag could be 2-4 °C above ambient during
midday. Data presented here were collected under the conditions in the
bag.

7.2.1 Temporal Coverage

Data were collected from 23-Jul-1996 until 14-Aug-1996.

7.2.2 Temporal Coverage Map

Not available.

7.2.3 Temporal Resolution

Data were collected every 5 minutes over each site for several
consecutive days.

7.3 Data Characteristics

7.3 Data Characteristics

Data characteristics are defined in the companion data definition file
(te04bbag.def).

7.4 Sample Data Record

Sample data format shown in the companion data definition file
(te04bbag.def).

8\. Data Organization

8.1 Data Granularity

All of the branch bag gas exchange measurements are in one file.

8.2 Data Format(s)

The data files contain American Standard Code for Information
Interchange (ASCII) numerical and character fields of varying length
separated by commas. The character fields are enclosed with single
apostrophe marks. There are no spaces between the fields. Sample data
records are shown in the companion data definition file (te04bbag.def).

9\. Data Manipulations

9.1 Formulae

Calculations of gas exchange parameters were conducted essentially as
described by Ball (1987).

9.1.1 Derivation Techniques and Algorithms used

See Section 9.1.

9.2 Data Processing Sequence

Data were logged by a laptop computer, and calculations were made
concurrent with the measurements. All of the primary data are archived.

9.2.1 Processing Steps

No averaging.

9.2.2 Processing Changes

9.3 Calculations

The calculations are as described by Ball (1987).

9.4 Graphs and Plots

Plots of these experiments are available as PostScript files by
anonymous ftp to biosphere.stanford.edu. Some of these may be found in
the directory /submissions/Boreas_data/PS_files or
http://biosphere.stanford.edu.

10\. Errors

10.1 Sources of Error

Uncertainty in these experiments arises from instrument noise and
systematic calibration errors, and because the leaf experiences somewhat
different conditions (e.g.) high temperature and Vapor Pressure Deficit
(VPD) than do leaves in natural environments.

10.2 Quality Assessment

10.2.1 Data Validation by Source

The data sets are being checked against calibrated equipment.

10.2.2 Confidence Level/Accuracy Judgment

These data have been carefully checked and are equal in quality to
measurements conducted under laboratory conditions.

10.2.3 Measurement Error for Parameters

Gsw, stomatal conductance, +/- 5 mmol/m^2^s

A, net CO~2~ exchange, +/- 0.1 micromole/m^2^s

Ci, intercellular CO~2~, +/- 5 micromole/mol

10.2.4 Additional Quality Assessments

None.

10.2.5 Data Verification by Data Center

Data were examined for general consistency and clarity.

11\. Notes

11.1 Limitations of the Data

Unknown.

11.2 Known Problems with the Data

Light interception by the enclosed crown varied with the ratio of direct
to diffuse radiation intercepted, and was calculated from measurements
of the projected area and geometric model of light interception.

11.3 Usage Guidance

Calibrated data sets and models for simulation or analysis of these data
can be obtained from J. Berry.

11.4. Other Relevant Information

None.

12\. Application of the Data Set

The data set has been simulated with a leaf version of the Land-Surface
Parameterization Model (SiB2) combining some special treatments of
radiation absorption. Preliminary estimates can be obtained from J.
Berry.

13\. Future Modification and Plans

None.

14\. Software

14.1 Software Description

SiB2 is in FORTRAN and runs in a workstation environment. The Collatz et
al. (1991), model is in C and can be run on PCs or workstations.

14.2 Software Access

Copies of SiB2 or the Collatz et al. (1991) model can be obtained from
J. Berry.

15\. Data Access

15.1 Contact Information

Ms. Beth Nelson

BOREAS Data Manager

NASA GSFC

Greenbelt,

\(301\) 286-4005

\(301\) 286-0239 (fax)

Elizabeth.Nelson@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-04 branch bag 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 ProductsNone.16.2 Film Products

None.

16.3 Other Products

These data are available on the BOREAS CD-ROM series.

17\. References

17.1 Platform/Sensor Instrument/Data Processing Documentation

None given.

17.2 Journal Articles and Study Reports

Ball, J.T. 1987. Calculations related to gas exchange. In: E. Zeiger,
G.D. Farquhar and I.R. Cowan (Eds.), Stomatal Function, Stanford
University Press, Stanford. 446-476.

Collatz, G.J., J.T. Ball, C. Grivet, and J.A. Berry. (1991).
Physiological and environmental regulation of stomatal conductance,
photosynthesis and transpiration: a model that includes a laminar
boundary layer. Agricultural and Forest Meteorology, 54, 107-36.

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., F. Hall, and K.F. Huemmrich. 1996. Boreal
Ecosystem-Atmosphere Study: 1994 Operations. NASA BOREAS Report (OPSDOC
94).

Sellers, P., F. Hall, and K.F. Huemmrich. 1997. Boreal
Ecosystem-Atmosphere Study: 1996 Operations. NASA BOREAS Report (OPSDOC
96).

Sellers, P.J., D.R. Randall, G.J. Collatz, J.A. Berry, C.B. Field, D.A.
Dazlich, and G.D. Collelo. 1996. A revised land-surface parameterization
(SiB2) for GCMs. Part 1: Model formulation. Journal of Climate, 9,
676-705.

Sellers, P.J., 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.
Bull. Am. Meteorol. Soc. 76:1549-1577.

Sellers, P.J., F.G. Hall, R.D. Kelly, A. Black, D. Baldocchi, J. Berry,
M. Ryan, K.J. Ranson, P.M. Crill, D.P. Lettenmaier, H. Margolis, J.
Cihlar, J. Newcomer, D. Fitzjarrald, P.G. Jarvis, S.T. Gower, D.
Halliwell, D. Williams, B. Goodison, D.E. Wickland, and F.E. Guertin.
1997. BOREAS in 1997: Experiment overview, scientific results, and
future directions. Journal of Geophysical Research, 102 (D24),
28731-28769.

17.3 Archive/DBMS Usage Documentation

None.

18\. Glossary of Terms

SiB2 - Land-Surface Parameterization Model

19\. List of Acronyms

ASCII - American Standard Code for Information Interchange

BOREAS - BOReal Ecosystem-Atmosphere Study

BORIS - BOREAS Information System

CD-ROM - Compact Disk-Read-Only memory

DAAC - Distributed Active Archive Center

DOY - Julian Day of Year

EOS - Earth Observing System

EOSDIS - EOS Data and Information System

GSFC - Goddard Space Flight Center

HTML - HyperText Markup Language

IFC - Intensive Field Campaign

IRGA - Infrared Gas Analyzer

MIX - Mixed Wood

NAD83 - North American Datum of 1983

NASA - National Aeronautics and Space Administration

NOAA - National Oceanic and Atmospheric Administration

NSA - Northern Study Area

ORNL - Oak Ridge National Laboratory

PANP - Prince Albert National Park

PAR - Photosynthetically Active Radiation

OA - Old Aspen

OBS - Old Black Spruce

OJP - Old Jack Pine

ORNL - Oak Ridge National Laboratory

SSA - Southern Study Area

TE - Terrestrial Ecology

TF - Tower Flux

URL - Uniform Resource Locator

UTM - Universal Transverse Mercator

VPD - Vapor Pressure Deficit

YA - Young Aspen Site

YJP - Young Jack Pine

20\. Document Information

20.1 Document Revision Date

Written: 23-Jun-1997

Last Updated: 09-Feb-1999

20.2 Document Review Date

BORIS Review: 23-Dec-1998

Science Review:

20.3 Document ID

20.4 Citation

Dr. Joseph A. Berry, Carnegie Institution of Washington, Stanford, CA,
94305

Dr. John Gamon, Department of Biology, CSU\--LA, LA, CA 90032

Dr. Wei Fu, Carnegie Institution of Washington, Stanford, CA, 94305

Dr. Art Fredeen, Faculty of Natural Rescources and Environmental
Studies, University of N.B.C., Prince George, B.C., Canada

20.5 Document Curator

20.6 Document URL

[Keywords]{.underline}

Branch Bag Photosynthesis

CO~2~ Concentration

Gas Exchange

Photosynthetically Active Radiation Flux Density

Steady-State System

Stomatal Conductance

Transpiration