Biomass of Sacrificed Spruce/Aspen (SNF): Data Set Guide Document Summary: Biophysical Data Introduction 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. Site Measurements 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 the dataset: "SNF Forest Cover by Species/Strata". 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)". Sacrificed Trees Dimension analysis of sampled trees were used to develop equations linking the convenience measurements taken at each site and the biophysical characteristics of interest (for example, LAI or biomass). To develop these relations, 32 aspen and 31 spruce trees were sacrificed. The trees were randomly sampled, with stratification by diameter, from stands similar and near to the study sites. Fifteen mountain maple and fifteen beaked hazelnut trees were also sampled and leaf area determined. These data were used to determine understory leaf area. For each sampled tree, diameter at breast height, height to first live branch and total height were measured before and after felling. Measurements of all branches included: height of attachment on bole, diameter, length to first secondary branch and total length. Crowns were vertically stratified into three equal sections and six branches were randomly sampled from each stratum. For each sampled branch, all leaves and wood were weighted green and the current year's woody growth was measured. A sample of 200 leaves from each stratum had leaf area measured with a Licor leaf area meter and were dried and weighed. Subsamples from each sampled branch were dried and weighed. Removal of green spruce needles from branches proved impractical, so needle bearing parts of sampled branches were cut off, separated between current year and older classes, and dried. A sample of 21 needles each from the new and older growth were randomly selected from each canopy stratum. The sampled needles were photographed and green and dry weights were measured. Projected area was determined from the digitized photographs. Boles were sectioned and weighed green. Four sections five to 20 centimeters long were cut from : the base of the bole;half-way between the base and first live branch; just below the first live branch; and half-way between the first live branch and the tree top. Each section was measured and dried and weighed. Parameter Estimation from Sampled Trees For each of the sacrificed trees the total above ground biomass was estimated as the sum of the branch and bole biomass. Branch biomass was estimated by finding the dry to green weight ratios for leaves, twigs and wood and using the ratios to convert the green to dry weights for the sampled branches. A regression of branch biomass on branch dimensions was done independently for each tree and used to determine biomass for the unsampled branches. Total branch biomass was the sum of the estimated biomass of the sampled and unsampled branches. Bole biomass was estimated by finding the dry to green weight ratios for each section, converting the green weights and summing. Total biomass is the sum of the branch and bole biomass. Methods for estimating leaf area were parallel to those for estimating branch biomass. Leaf weights for unsampled branches were estimated using tree-specific, linear regressions on branch dimensions fit with data from sampled branches. For spruce, separate regressions were done for current year and older needles. Measured and estimated foliage weights were summed within strata and, for spruce, age class. The foliage weights were converted to leaf areas using ratios determined from sampled leaves, then totaled for trees. The sacrificied tree statistics for aspen and spruce are provided in this data set "Biomass of Sacrificed Spruce/Aspen (SNF)". Bark area in aspen was determined using similar techniques to those for leaf area. Sampled branches were divided into segments, each segment was assumed to be a cylinder and the surface area was calculated. Total branch surface area was the sum of the surface areas of the segments. A regression was developed to determine branch area for the unsampled branches. The sum of the estimated branch areas for the sampled and unsampled branches is the total bark area. Net primary productivity was estimated from the average radial growth over five years measured from the segments cut from the boles and the terminal growth measured as the height increase of the tree. Allometric equations were used to find the height and radial increment as a function of crown height and diameter at breast height. Spruce used an additional parameter of stem density. The models were used to back project five years and determine biomass at that time. The change in biomass over that time was used to determine the productivity. Measurements of the sacrificed trees were used to develop relationships between the biophysical parameters (biomass, leaf area index, bark area index and net primary productivity) and the measurements made at each site (diameter at breast height, tree height, crown depth and stem density). These relationships were then used to estimate biophysical characteristics for the aspen and spruce study sites that are provided in the data set "Forest Biophysical Parameters (SNF)". Stand Characteristics Aspen is an early successional, shade intolerant species. Aspen stands are essentially even aged, and stand age appears to be the most significant difference among sites in determining stand density, average diameter, and biomass density. Biomass density was highest in stands of older, larger trees and decreased in younger stands with smaller, denser stems. Since all aspen stands had closed canopies, the inverse relationship between biomass density and stem density suggests a series of stands in various stages of self thinning. Aspen trees do not survive suppression, so that bole diameters tend to be relatively uniform and age-determined and biomass increases with age and diameter while density declines. LAI, however, remains relatively constant once a full canopy is established with aspen's shade intolerance generally preventing development of LAI greater than two to three. Biomass density and projected LAI were much more variable for spruce than aspen. Spruce LAI and biomass density have a tight, nearly linear relationship. Stand attributes are often determined by site characteristics. Wet, ombrotrophic sites support open, low biomass, mixed age stands. Spruce stands with LAI below about two and biomass densities below about five kilograms per square meter appear to be limited by site characteristics such as nutrient poverty and wetness. Stand quality improves with site richness until canopy closure brings on self thinning. Closed canopies attain maximum LAI at around four, higher than aspen, perhaps because spruce is more shade tolerant (it is often observed growing beneath closed aspen stands in the study area). However, differences between maximum LAI for aspen and spruce may also be related to differences in the leaf distribution within the canopy. Phenology Deciduous vegetation undergoes dramatic changes over the seasonal cycle. The varying amount of green foliage in the canopy effects the transpiration and productivity of the forest. Measurements of changes in the canopy and subcanopy green foliage amount over the spring of 1984 have been made. From above the subcanopy, photographs of the aspen canopy were taken, pointing vertically up. The photographs were taken at two locations in sites 16 and 93 on several different days. Foliage coverage was determined by overlaying grids with 200 points onto the photos of the canopy. The number of points obscured by vegetation were counted. These counts were adjusted for the area of the branches, which had been determined by photos taken before leaf out. The number of foliage points were then scaled between zero, for no leaves, to one, for maximum coverage. Subcanopy leaf extension was measured for beaked hazelnut and mountain maple, the two most common understory shrubs. For selected branches on trees in sites 16 and 93, the length and width of all leaves were measured on several days. These measurements were used to calculate a total leaf area which was scaled between 0 and 1 as with the aspen. The aspen canopy measurements have been combined with the subcanopy measurements and are available in the data set "SNF Forest Phenology/Leaf Expansion Data". These measurements of leafout show that the subcanopy leaf expansion lags behind that of the canopy. Subcanopy leaf expansion only begins in earnest after the canopy has reached nearly full coverage. 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: Biomass of Sacrificed Spruce/Aspen (SNF) Data Set Introduction: Objective/Purpose: Biophysical Data Introduction 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: Diameter at breast high, depth of crown, tree height, total leaf area, standard deviation of total leaf area, biomass, and standard deviation of biomass. Discussion: Site Measurements 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 the dataset: "SNF Forest Cover by Species/Strata". 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)". Sacrificed Trees Dimension analysis of sampled trees were used to develop equations linking the convenience measurements taken at each site and the biophysical characteristics of interest (for example, LAI or biomass). To develop these relations, 32 aspen and 31 spruce trees were sacrificed. The trees were randomly sampled, with stratification by diameter, from stands similar and near to the study sites. Fifteen mountain maple and fifteen beaked hazelnut trees were also sampled and leaf area determined. These data were used to determine understory leaf area. For each sampled tree, diameter at breast height, height to first live branch and total height were measured before and after felling. Measurements of all branches included: height of attachment on bole, diameter, length to first secondary branch and total length. Crowns were vertically stratified into three equal sections and six branches were randomly sampled from each stratum. For each sampled branch, all leaves and wood were weighted green and the current year's woody growth was measured. A sample of 200 leaves from each stratum had leaf area measured with a Licor leaf area meter and were dried and weighed. Subsamples from each sampled branch were dried and weighed. Removal of green spruce needles from branches proved impractical, so needle bearing parts of sampled branches were cut off, separated between current year and older classes, and dried. A sample of 21 needles each from the new and older growth were randomly selected from each canopy stratum. The sampled needles were photographed and green and dry weights were measured. Projected area was determined from the digitized photographs. Boles were sectioned and weighed green. Four sections five to 20 centimeters long were cut from : the base of the bole;half-way between the base and first live branch; just below the first live branch; and half-way between the first live branch and the tree top. Each section was measured and dried and weighed. Parameter Estimation from Sampled Trees For each of the sacrificed trees the total above ground biomass was estimated as the sum of the branch and bole biomass. Branch biomass was estimated by finding the dry to green weight ratios for leaves, twigs and wood and using the ratios to convert the green to dry weights for the sampled branches. A regression of branch biomass on branch dimensions was done independently for each tree and used to determine biomass for the unsampled branches. Total branch biomass was the sum of the estimated biomass of the sampled and unsampled branches. Bole biomass was estimated by finding the dry to green weight ratios for each section, converting the green weights and summing. Total biomass is the sum of the branch and bole biomass. Methods for estimating leaf area were parallel to those for estimating branch biomass. Leaf weights for unsampled branches were estimated using tree-specific, linear regressions on branch dimensions fit with data from sampled branches. For spruce, separate regressions were done for current year and older needles. Measured and estimated foliage weights were summed within strata and, for spruce, age class. The foliage weights were converted to leaf areas using ratios determined from sampled leaves, then totaled for trees. The sacrificied tree statistics for aspen and spruce are provided in this data set "Biomass of Sacrificed Spruce/Aspen (SNF)". Bark area in aspen was determined using similar techniques to those for leaf area. Sampled branches were divided into segments, each segment was assumed to be a cylinder and the surface area was calculated. Total branch surface area was the sum of the surface areas of the segments. A regression was developed to determine branch area for the unsampled branches. The sum of the estimated branch areas for the sampled and unsampled branches is the total bark area. Net primary productivity was estimated from the average radial growth over five years measured from the segments cut from the boles and the terminal growth measured as the height increase of the tree. Allometric equations were used to find the height and radial increment as a function of crown height and diameter at breast height. Spruce used an additional parameter of stem density. The models were used to back project five years and determine biomass at that time. The change in biomass over that time was used to determine the productivity. Measurements of the sacrificed trees were used to develop relationships between the biophysical parameters (biomass, leaf area index, bark area index and net primary productivity) and the measurements made at each site (diameter at breast height, tree height, crown depth and stem density). These relationships were then used to estimate biophysical characteristics for the aspen and spruce study sites that are provided in the data set "Forest Biophysical Parameters (SNF)". Stand Characteristics Aspen is an early successional, shade intolerant species. Aspen stands are essentially even aged, and stand age appears to be the most significant difference among sites in determining stand density, average diameter, and biomass density. Biomass density was highest in stands of older, larger trees and decreased in younger stands with smaller, denser stems. Since all aspen stands had closed canopies, the inverse relationship between biomass density and stem density suggests a series of stands in various stages of self thinning. Aspen trees do not survive suppression, so that bole diameters tend to be relatively uniform and age-determined and biomass increases with age and diameter while density declines. LAI, however, remains relatively constant once a full canopy is established with aspen's shade intolerance generally preventing development of LAI greater than two to three. Biomass density and projected LAI were much more variable for spruce than aspen. Spruce LAI and biomass density have a tight, nearly linear relationship. Stand attributes are often determined by site characteristics. Wet, ombrotrophic sites support open, low biomass, mixed age stands. Spruce stands with LAI below about two and biomass densities below about five kilograms per square meter appear to be limited by site characteristics such as nutrient poverty and wetness. Stand quality improves with site richness until canopy closure brings on self thinning. Closed canopies attain maximum LAI at around four, higher than aspen, perhaps because spruce is more shade tolerant (it is often observed growing beneath closed aspen stands in the study area). However, differences between maximum LAI for aspen and spruce may also be related to differences in the leaf distribution within the canopy. Phenology Deciduous vegetation undergoes dramatic changes over the seasonal cycle. The varying amount of green foliage in the canopy effects the transpiration and productivity of the forest. Measurements of changes in the canopy and subcanopy green foliage amount over the spring of 1984 have been made. From above the subcanopy, photographs of the aspen canopy were taken, pointing vertically up. The photographs were taken at two locations in sites 16 and 93 on several different days. Foliage coverage was determined by overlaying grids with 200 points onto the photos of the canopy. The number of points obscured by vegetation were counted. These counts were adjusted for the area of the branches, which had been determined by photos taken before leaf out. The number of foliage points were then scaled between zero, for no leaves, to one, for maximum coverage. Subcanopy leaf extension was measured for beaked hazelnut and mountain maple, the two most common understory shrubs. For selected branches on trees in sites 16 and 93, the length and width of all leaves were measured on several days. These measurements were used to calculate a total leaf area which was scaled between 0 and 1 as with the aspen. The aspen canopy measurements have been combined with the subcanopy measurements and are available in the data set "SNF Forest Phenology/Leaf Expansion Data". These measurements of leafout show that the subcanopy leaf expansion lags behind that of the canopy. Subcanopy leaf expansion only begins in earnest after the canopy has reached nearly full coverage. Related Data Sets: Aspen Forest Cover by Stratum/Plot (SNF) Forest Biophysical Parameters (SNF) Forest Canopy Composition (SNF) SNF Forest Cover by Species/Strata SNF Forest Understory Cover Data SNF Forest Understory Cover Data (Table) 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 dbh DBH 8 NUMBER(4,1) "Diameter breast height (cm)" **************************************************************************** 2 tree_ht TREE_HEIGHT 8 NUMBER(5,2) "Total tree height (m)" **************************************************************************** 3 doc CROWN_DEPTH 8 NUMBER(5,2) "Depth of crown (m), measured from the base to the top of the crown" **************************************************************************** 4 tla TOTAL_LEAF_AREA 8 NUMBER(9,2) "Total leaf area (cm2)" **************************************************************************** 5 sla STDEV_LEAF_AREA 8 NUMBER(9,2) "Standard deviation of total leaf area (cm2)" **************************************************************************** 6 biomass BIOMASS 8 NUMBER(9,2) "Total tree biomass (g)" **************************************************************************** 7 bio_se STDEV_BIOMASS 8 NUMBER(9,2) "Standard deviation of total tree biomass (g)" **************************************************************************** 8 species SPECIES_CODE $ 12 CHAR(6) "Plant species (Aspen/Spruce)" **************************************************************************** Sample Data Record: dbh tree_ht doc tla sla biomass bio_se species 0.9 2.2 1.78 1280.16 0 112.58 2.1 "Aspen" 1.2 2.8 1.77 1766.12 165.46 168.7 24.25 "Aspen" 1.4 3.43 2.14 3677.92 290.14 256.28 8.83 "Aspen" 1.8 3.78 2.62 9708.01 1685.75 598.47 70.36 "Aspen" 2 4.6 2.4 9043.15 814.04 567.4 19.03 "Aspen" 2.2 3.1 1.8 11658.8 1771.7 606.54 16.69 "Aspen" 3.4 5.7 4.43 20256.21 853.54 1909.26 37.94 "Aspen" 3.4 5.35 4.05 32123.67 3891.72 1936.82 59.93 "Aspen" 3.5 5.35 4.15 14072.01 818.25 1532.02 29.73 "Aspen" 7.3 9.2 4.9 102891.09 19216.2 14346.3 621.48 "Aspen" 9.1 9.4 4.42 83769.87 9591.3 11250.38 313.15 "Aspen" 10.5 11.5 5.3 148084.39 11454.91 29413.23 966.04 "Aspen" 13 16.1 5.05 109339.86 12714.04 54486.61 1178.68 "Aspen" 13.7 15.9 4.65 108924.04 8857.67 60834.46 1118.45 "Aspen" 15.1 16.7 6.95 91855.49 4814.76 67338.04 1262.27 "Aspen" 15.4 17.4 7.1 138091.91 8771.01 80391.1 1515.08 "Aspen" 15.8 15.6 5.4 193240.13 8073.15 71016.01 1280.61 "Aspen" 17.3 15.5 8.4 218524.41 6802.89 73012.54 1162.92 "Aspen" 19.4 23 10.3 312907.63 10882.57 171922.24 2513.05 "Aspen" 19.5 19.35 7.4 175246.08 10190.74 107218.69 1803 "Aspen" 21.5 23.1 5.75 182521.34 19549.84 177285.82 2196.16 "Aspen" 22.5 22.5 7.25 500455.06 41004.35 238477.34 3218.93 "Aspen" 22.6 18.1 7.4 287153.53 11609.84 191767.73 2248.49 "Aspen" 22.8 22.4 6.6 422196.53 23861.99 233177.57 2992.33 "Aspen" 23 22.5 8.7 382654.5 12988.99 237964 3036.38 "Aspen" 25.1 23.8 8.85 273654.69 23332.5 274651.8 3343.34 "Aspen" 25.2 22.5 8.8 241456.02 49253.56 270825.85 3766.19 "Aspen" 27.8 23.5 16.25 745781 73361.2 448440.07 6264.33 "Aspen" 30.2 23.5 10.05 743229.75 71937.2 437031.91 5502.92 "Aspen" 32.1 23.8 8.9 531668.81 71937.81 456140.4 4753.74 "Aspen" 32.4 23.5 12.8 1017735.38 91915.13 533887.77 5360.41 "Aspen" 35.4 22.5 11.5 1228601.5 112045.76 559046.9 5050.19 "Aspen" 2.9 2.9 1.66 8303.5 1307.83 957.73 59.84 "Spruce" 4.1 3.7 3.6 28230.51 5520.61 3541.01 230.67 "Spruce" 4.1 4.37 4.24 42984.57 18818.73 5251.89 445.79 "Spruce" 4.4 4.2 2.61 19539.94 2915.01 3286.88 152.28 "Spruce" 4.9 5.6 2.15 13361.46 2415.06 3720.22 320.19 "Spruce" 5.1 4.15 1.9 18259.08 1675.77 4389.37 105.35 "Spruce" 5.5 8.55 5 37405.26 4111.27 6242.02 260.35 "Spruce" 5.7 6 3.1 46803.37 2895.23 6177.99 376.14 "Spruce" 6.9 6.9 5.12 46080.43 6772.37 8869.33 233.97 "Spruce" 8.2 9.35 3.55 34179.43 5821.31 14609.92 377.44 "Spruce" 9.1 10.56 4.82 57286.88 7504.3 16967.75 622.87 "Spruce" 9.2 11.7 3.4 50016.85 6077.54 19912.67 411.31 "Spruce" 11 12.86 5.11 115016.66 12092.5 35581.93 581.85 "Spruce" 11 10.9 7.5 115095.3 18986.75 31188.5 716.32 "Spruce" 11.5 12.6 7.55 160659.06 15806.49 43375.69 942.15 "Spruce" 12.1 11 4 93923.11 14070.42 32544.85 876.03 "Spruce" 12.7 14.7 7.7 77944.05 17154.32 45656.59 1637.72 "Spruce" 14.1 11.94 9.38 165289.27 27741.48 53860.68 2846.02 "Spruce" 14.3 13.9 7.8 335712.03 29299.56 60976.55 1218.13 "Spruce" 14.4 13.1 7.5 119594.65 21101.48 52109.21 1331.45 "Spruce" 15.6 14.4 8 66331.88 6845.71 59780.82 917.52 "Spruce" 15.6 13.1 8.15 115336.13 22047.93 62144.07 1152.5 "Spruce" 16.4 11.8 8.5 438570.81 73382.71 70466.63 1878.4 "Spruce" 18.1 19.9 8.65 214715.11 36310.12 133180.07 2484.47 "Spruce" 18.9 18.8 8.43 241654.33 34868.48 128709.13 2019.3 "Spruce" 19 14.15 12.43 450936.09 69085.73 114136 2979.51 "Spruce" 19.6 14.7 10.47 298449.13 45453.35 114821.05 3087.88 "Spruce" 20.2 14.6 12.4 243767.86 27349.37 128890.17 3164.18 "Spruce" 20.8 15.3 7.27 146029.06 24910.89 104981.92 2439.91 "Spruce" 22.8 17.5 10.1 239635.28 37735.02 137075.67 2088.36 "Spruce" 23 19.95 12.49 492978.78 60853.75 204608.74 6718.3 "Spruce" Footnote: For presentation in this document, some padding blanks may have been eliminated between columns in the Sample Data Record. See the Data Format section for conventions used for missing data values in the data file. 8. Data Organization: Data are sorted by species (Aspen or Spruce) and diameter at breast high (dbh). Data Granularity: This data set consists of a single ASCII file containing leaf area, biomass, depth of crown and diameter at breast high for aspen and spruce trees. 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_BIOMASS 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