SNF Forest Cover by Species/Strata: Data Set Guide Document Summary: The purpose of the SNF study was to improve our understanding of the relationship between remotely sensed observations and important biophysical parameters in the boreal forest. A key element of the experiment was the development of methodologies to measure forest stand characteristics to determine values of importance to both remote sensing and ecology. Parameters studied were biomass, leaf area index, above ground net primary productivity, bark area index and ground coverage by vegetation. Thirty two quaking aspen and thirty one black spruce sites were studied. Sites were chosen in uniform stands of aspen or spruce. The dominant species in the site constituted over 80 percent, and usually over 95 percent, of the total tree density and basal area. Aspen stands were chosen to represent the full range of age and stem density of essentially pure aspen, of nearly complete canopy closure, and greater than two meters in height. Spruce stands ranged from very sparse stands on bog sites, to dense, closed stands on more productive peatlands. In each stand a uniform site 60 meters in diameter was laid out. Within this site, five circular plots, 16 meters in diameter, were positioned. One plot was at the center of the site and four were tangent to the center plot, one each in the cardinal directions. In very dense stands, plot radii were decreased so that stem count for the five plots remained around 200 stems. Use of multiple plots within each site allowed estimation of the importance of spatial variation in stand parameters. Within each plot, all woody stems greater than two meters in height were recorded by species and relevant dimensions were measured. Diameter breast height (dbh) was measured directly. Height of the tree and height of the first live branch were determined by triangulation. The difference between these two heights was used as the depth of crown. The distances between trees and observer were such that no angle exceeded 65 degrees. Most plots were level, small slopes were ignored in calculating heights. Similar measurements were made for shrubs between one and two meters tall in the aspen sites. The data set "Forest Canopy Composition (SNF)" provides the counts of canopy (over two meters tall) tree species and subcanopy (between one and two meters tall) tree species. For each plot, a two meter diameter subplot was defined at the center of each plot. Within this subplot, the percent of ground coverage by plants under one meter in height was determined by species. These data, averaged for the five plots in each site, are presented in the data set, "SNF Forest Understory Cover Data (Table)" in tabular format, e.g. plant species with a count for that species at each site. The same data are presented in the data set "SNF Forest Understory Cover Data" but are arranged with a row for each species and site and a percent ground coverage for each combination. In addition, these data sets: canopy, subcanopy, and understory counts have been combined into this dataset: "SNF Forest Cover by Species/Strata". Also related, for the aspen sites, in each plot a visual estimation of the percent coverage of the canopy, subcanopy and understory vegetation was made. The site averages of these coverage estimates are presented in the data set "Aspen Forest Cover by Stratum/Plot (SNF)". Tables of Contents: 1. Data Set Overview 2. Investigator(s) 3. Theory of Measurements 4. Equipment 5. Data Acquisistion Methods 6. Observations 7. Data Description 8. Data Manipulations 9. Data Organization 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: Data Set Identification: SNF Forest Cover by Species/Strata Data Set Introduction: This data set is a composite of the canopy, subcanopy, and understory vegetation counts and percent ground coverages by site ID and vegetation species. Objective/Purpose: The purpose of the SNF study was to improve our understanding of the relationship between remotely sensed observations and important biophysical parameters in the boreal forest. A key element of the experiment was the development of methodologies to measure forest stand characteristics to determine values of importance to both remote sensing and ecology. Parameters studied were biomass, leaf area index, above ground net primary productivity, bark area index and ground coverage by vegetation. Thirty two quaking aspen and thirty one black spruce sites were studied. Summary of Parameters: Canopy, subcanopy and understory vegetation phenology, percent ground coverage. Discussion: Sites were chosen in uniform stands of aspen or spruce. The dominant species in the site constituted over 80 percent, and usually over 95 percent, of the total tree density and basal area. Aspen stands were chosen to represent the full range of age and stem density of essentially pure aspen, of nearly complete canopy closure, and greater than two meters in height. Spruce stands ranged from very sparse stands on bog sites, to dense, closed stands on more productive peatlands. In each stand a uniform site 60 meters in diameter was laid out. Within this site, five circular plots, 16 meters in diameter, were positioned. One plot was at the center of the site and four were tangent to the center plot, one each in the cardinal directions. In very dense stands, plot radii were decreased so that stem count for the five plots remained around 200 stems. Use of multiple plots within each site allowed estimation of the importance of spatial variation in stand parameters. Within each plot, all woody stems greater than two meters in height were recorded by species and relevant dimensions were measured. Diameter breast height (dbh) was measured directly. Height of the tree and height of the first live branch were determined by triangulation. The difference between these two heights was used as the depth of crown. The distances between trees and observer were such that no angle exceeded 65 degrees. Most plots were level, small slopes were ignored in calculating heights. Similar measurements were made for shrubs between one and two meters tall in the aspen sites. The data set "Forest Canopy Composition (SNF)" provides the counts of canopy (over two meters tall) tree species and subcanopy (between one and two meters tall) tree species. For each plot, a two meter diameter subplot was defined at the center of each plot. Within this subplot, the percent of ground coverage by plants under one meter in height was determined by species. These data, averaged for the five plots in each site, are presented in the data set, "SNF Forest Understory Cover Data (Table)" in tabular format, e.g. plant species with a count for that species at each site. The same data are presented in the data set "SNF Forest Understory Cover Data" but are arranged with a row for each species and site and a percent ground coverage for each combination. In addition, these data sets: canopy, subcanopy, and understory counts have been combined into this dataset: "SNF Forest Cover by Species/Strata". Also related, for the aspen sites, in each plot a visual estimation of the percent coverage of the canopy, subcanopy and understory vegetation was made. The site averages of these coverage estimates are presented in the data set "Aspen Forest Cover by Stratum/Plot (SNF)". Related Data Sets: Forest Canopy Composition (SNF) SNF Forest Understory Cover Data (Table) SNF Forest Understory Cover Data Aspen Forest Cover by Stratum/Plot (SNF) 2. Investigator(s): Investigator(s) Name and Title: Dr. Forrest G. Hall NASA Goddard Space Flight Center Dr. K. Fred Huemmrich NASA Goddard Space Flight Center Dr. Donald E. Strebel Versar, Inc. Dr. Scott J. Goetz Universtity of Maryland Ms. Jaime E. Nickeson NASA Goddard Space Flight Center Dr. Kerry D. Woods Bennington College Dr. Celeste Jarvis NASA Headquarters Title of Investigation: Contact Information: Dr. Forrest G. Hall NASA Goddard Space Flight Center Code 923 Greenbelt, Maryland 20771 USA Fax +1 (301) 286-0239 Telephone +1 (301) 286-2974 Email: fghall@ltpmail.gsfc.nasa.gov Requested Form of Acknowledgememt: Please cite the following NASA Technical Memorandum 104568 in any work or any publication using these data: Hall, F.G., K.F. Huemmrich, D.E. Strebel, S.J. Goetz, J.E. Nickeson, and K.D. Woods, July 1992. Biophysical, Morphological, Canopy Optical Property, and Productivity Data From the Superior National Forest. NASA Technical Memorandum 104568. National Aeronautics and Space Administration, Washington, D.C. 20546. 3. Theory of Measurements: 4. Equipment: Sensor/Instrument Description: Collection Environment: Ground-based. Source/Platform: Source/Platform Mission Objectives: Key Variables: Principles of Operation: Sensor/Instrument Measurement Geometry: Manufacturer of Sensor/Instrument: 5.2 Calibration: Calibration: Specifications: Tolerance: Frequency of Calibration: Other Calibration Information: 5. Data Acquisition Methods: 6. Observations: Data Notes: Not Available. Field Notes: 7. Data Description: Spatial Characteristics: Spatial Coverage: Spatial Coverage Map: Not Available. Spatial Resolution: Projection: Not Available. Grid Description: Not Available. Temporal Characteristics: Temporal Coverage: Temporal Coverage Map: Not Available. Temporal Resolution: Data Characteristics: **************************************************************************** Variable Name/ Long Name SAS Type Generic Type Description ---------------------------------------------------------------------------- 1 site_id 8 "Site ID" ---------------------------------------------------------------------------- 2 speccode $ 10 "Plant species code [see speccomm (Common Name) and spec_sci (Latin Name)]" ---------------------------------------------------------------------------- 3 can_spec $ 1 "Canopy species? (y/n)" ---------------------------------------------------------------------------- 4 subcspec $ 1 "Subcanopy species? (y/n)" ---------------------------------------------------------------------------- 5 count1 8 "Count of trees 1-2 meters tall" ---------------------------------------------------------------------------- 6 count2 8 "Count of trees > 2 meters tall" ---------------------------------------------------------------------------- 7 pct_cvr 8 "Average percent ground coverage" ---------------------------------------------------------------------------- 8 under_st $ 1 "Understory species? (y/n)" ---------------------------------------------------------------------------- 9 in_can 8 "Species in canopy at site? (1=y/0=n)" ---------------------------------------------------------------------------- 10 in_subc 8 "Species in subcanopy at site? (1=y/0=n)" ---------------------------------------------------------------------------- 11 in_under 8 "Species in understory at site? (1=y/0=n)" ---------------------------------------------------------------------------- 12 speccomm COMMON_NAME $ 36 CHAR(20) "Plant species common name" ---------------------------------------------------------------------------- 13 spec_sci LATIN_NAME $ 36 CHAR(25) "The Latin (botanical) name of the species" **************************************************************************** Sample Data Record: site_id speccode can_spec subcspec count1 count2 pct_cvr under_st in_can in_subc in_under speccomm spec_sci 2 "ABBA" "Y" " " . 0 0 "Y" 1 0 1 "Fir, Balsam" "Abies Balsamea " 3 "ABBA" "Y" "Y" 0 0 0 "Y" 1 1 1 "Fir, Balsam" "Abies Balsamea " 8 "ABBA" "Y" " " . 2 . " " 1 0 0 "Fir, Balsam" "Abies Balsamea " 10 "ABBA" "Y" " " . 7 . " " 1 0 0 "Fir, Balsam" "Abies Balsamea " 12 "ABBA" "Y" " " . 0 0 "Y" 1 0 1 "Fir, Balsam" "Abies Balsamea " 14 "ABBA" "Y" " " . 0 0 "Y" 1 0 1 "Fir, Balsam" "Abies Balsamea " 15 "ABBA" "Y" " " . 0 0 "Y" 1 0 1 "Fir, Balsam" "Abies Balsamea " 16 "ABBA" "Y" "Y" 0 2 0 "Y" 1 1 1 "Fir, Balsam" "Abies Balsamea " 18  "ABBA" "Y" " " . 0 0 "Y" 1 0 1 "Fir, Balsam" "Abies Balsamea " Footnote: For presentation in this document, padding blanks have been eliminated between columns in the Sample Data Record. See Data Format section for conventions used for missing data values in the data file. 8. Data Organization: Data are sorted by species code (speccode) and study site (site_id). Key fields in each record are site_id and speccode. Data Granularity: This data set consists of a single ASCII file containing counts of vegetation individuals and average percent cover at each site by those vegetation species for all canopy layers. Data Format: The data files associated with this data set consist of numeric and character fields of varying lengths aligned in columns. The first row of each data file contains the 8-character SAS variable name that links to the data format definition file. Character fields are enclosed in double quotes and numeric fields are listed without quotes. Missing data values can be of two varieties: * values that were identified as missing in the original data files Missing numeric values of this type are identified in these data as -999. * those holes that were created as a result of combining files that contained a slightly different variable set. Missing values of this type are identified in these data files as empty double quotes for character fields and a single period, '.' for numeric fields. 9. Data Manipulations: Formulae: Derivation Techniques and Algorithms: Data Processing Sequence: Processing Steps: Processing Changes: None. Calculations: None available at this revision. Special Corrections/Adjustments: None known at this revision. Calculated Variables: Data Processing by Data Center: The Superior National Forest data was received from the Goddard Space Flight Center in three media: * as data dumps from the original Oracle SNF database maintained by GSFC, transferred electronically from the GSFC system to the ORNL system * as ASCII files that mirrored the tables published in the Tech Memo * as hard copy (Tech Memo) Data from both electronic sources were input into SAS by ORNL DAAC data management staff and compared using computer code developed to process the SNF data. In many cases, the data values from both sources were found to be identical. In some cases, however, differences were identified and the providers of the data were consulted to resolve inconsistencies. Additionally, some variable columns were available in one source, but not the other for various reasons. For example, some calculated variables/columns were provided in the ASCII files (reflecting the Tech Memo tables) that were not stored in the Oracle database for purposes of space conservation. For similar reasons, coded values were used for many of the site and species identifier variables. A separate reference table was provided to link the coded variable with its definition, e.g., the SPECIES_REF file and the SITE_REF file. The database produced by the ORNL DAAC is a hybrid product that is a composite of data and information extracted from all three source media. In data sets where coded variables were included, the code definition variables have been added to improve usability of the data set as a stand-alone product. Therefore the ASCII files that are available through the ORNL DAAC on-line search and order systems are output from a data set that is a product of the essential core of numeric data provided by the data source (GSFC), augmented with additional descriptive information provided by GSFC and reorganized by the ORNL DAAC into a data structure consistent with other similar data sets maintained by the ORNL DAAC. Data Center Processing Steps: Graphs and Plots: None available at this revision. 10. Errors: Sources of Error: Quality Assessment: Data Validation by Source: Confidence Level/Accuracy Judgement: Measurement Error for Parameters: Additional Quality Assessments: Data Verification by Data Center: 11: Notes: Limitations of the Data: Not Available. Known Problems with the Data: None known at this revision. Usage Guidance: Any Other Relevant Information about the Study: None. 12. Application of the Data Set: 13. Future Modifications and Plans: None known at this revision. 14. Software: 15. Data Access: ORNL DAAC User Services P.O. Box 2008 Mail Stop 6407 Oak Ridge National Laboratory Oak Ridge, TN 37831-6407 USA Telephone: 423-241-3952 FAX: 423-574-4665 Email: ornldaac@ornl.gov Data Center Identification: EOSDIS Distributed Active Archive Center P.O. Box 2008 Mail Stop 6407 Oak Ridge National Laboratory Oak Ridge, TN 37831-6407 USA Telephone: 423-241-3952 FAX: 423-574-4665 Email: ornldaac@ornl.gov Procedures for Obtaining Data: Users may place requests by letter, telephone, electronic mail, FAX, or personal visit. Data is also available via the World Wide Web at http://www-eosdis.ornl.gov Data Center Status/Plans: The Superior National Forest Data is available from the ORNL DAAC. Please contact the ORNL DAAC User Services Office for the most current information about these data. 16. Output Products and Availability: 17. References: Satellite/Instrument/Data Processing Documentation: Journal Articles and Study Reports: Archive/DBMS Usage Documentation: Contact the EOS Distributed Active Archive Center (DAAC) at Oak Ridge National Laboratory (ORNL), Oak Ridge, Tennessee (see the Data Center Identification Section). Documentation about using the archive and/or online access to the data is not available at this revision. 18. Glossary of Terms: A general glossary for the DAAC is located at http://www-eosdis.ornl.gov/glossary.html 19. List of Acronyms: 20. Document Information: Date Written: October 10, 1996 Document Review Date: Document ID: ORNL-SNF_SITECOMP Citation: Document Author: Merilyn J. Gentry mjg@walden.rmt.utk.edu Document URL: http://www-eosdis.ornl.gov ------------------------------------------------------------------------------ ORNL DAAC User Services Office: 423-241-3952; email ornldaac@ornl.gov Web Document Curator: Sarah Jennings, xqj@ornl.gov Document Editor: Donna Lambert Revision Date: URL: http://www-eosdis.ornl.gov