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Data Set ID:

SMAPVEX12 In Situ Vegetation Data for Forest Area, Version 1

This data set contains in situ vegetation data collected at several forest sites as a part of the Soil Moisture Active Passive Validation Experiment 2012 (SMAPVEX12).

This is the most recent version of these data.

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Data: Data integrity and usability verified

Documentation: Key metadata and user guide available

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  • Vegetation > Canopy Characteristics > Angle of Branches
  • Vegetation > Canopy Characteristics > Canopy Height
  • Vegetation > Diameter at Breast Height (DBH)
  • Vegetation > Canopy Characteristics > Length of Branches
  • Vegetation > Canopy Characteristics > Number of Branches
  • Vegetation > Plant Characteristics > Thickness
  • Vegetation > Plant Characteristics > Trunk Height
  • Vegetation > Plant Characteristics > Understory Height
  • Vegetation > Biomass > Volume
  • Vegetation > Biomass > Weight
Data Format(s):
  • Microsoft Excel
Spatial Coverage:
N: 49.96, 
S: 49.44, 
E: -97.85, 
W: -98.51
Spatial Resolution:
  • 10 m
  • Varies
Temporal Coverage:
  • 7 June 2012 to 17 July 2012
Temporal Resolution1 dayMetadata XML:View Metadata Record
Data Contributor(s):Mahta Moghaddam

Geographic Coverage

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As a condition of using these data, you must cite the use of this data set using the following citation. For more information, see our Use and Copyright Web page.

Moghaddam, M. 2014. SMAPVEX12 In Situ Vegetation Data for Forest Area, Version 1. [Indicate subset used]. Boulder, Colorado USA. NASA National Snow and Ice Data Center Distributed Active Archive Center. doi: [Date Accessed].

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The documentation for this data set was provided solely by the Principal Investigator(s), and was not further developed, thoroughly reviewed, or edited by NSIDC. Thus, support for this data set may be limited.

Detailed Data Description

This data set contains in situ vegetation data collected at several forest sites as a part of the Soil Moisture Active Passive Validation Experiment 2012 (SMAPVEX12).


Data are provided in Microsoft Excel (.xlsx) format and Associated Extensible Markup Language (.MET.xml) format.

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File and Directory Structure

Data files are available on the HTTPS site in the directory. Within this directory there is one folder named 2012.06.07. Within this folder there are 10 files: five Excel files (.xlsx) and five associated Extensible Markup Language (.MET.xml) metadata files.

The data files and their contents are as follows:

SMAPVEX_Forest_VegDATA_final_8Jan.xlsx contains site survey information.
SMAPVEX_Forest_FN_intensive sampling_final_8Jan.xlsx contains intensive sampling of one tree per site.
Field_Sites_ver4_coords.txt contains location of the sampling sites.

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File Naming Convention

This section explains the file naming convention used for this data set with an example.

Example File Name: SV12VF_SMAPVEX_Forest_VegDATA_final_8Jan.xlsx

The following tables provide descriptions for each column in the Excel data files.

The north-south and east-west transects of each site (F1, F2, F3, and F5) have their own worksheet within the SV12VF_SMAPVEX_Forest_VegDATA_final_8Jan.xlsx file with the following columns:

Table 1. Data Column Descriptions for SV12VF_SMAPVEX_Forest_VegDATA_final_8Jan.xlsx
Column Heading Description
SITE ID ID of the site
TREE # Number of the tree along the transect
10M BIN Distance of the tree to the starting point of the transect
NOTE TO TREE Notes regarding the trees
DBH (IN) PREV Diameter at breast height
DBH (IN) UPD Diameter at breast height
HEIGHT (M) Height of the tree
SPECIES Species of the tree
TYPE FLAG Flag indicating the type of the tree
TRUNK HEIGHT (M) Height of the trunk of the tree
# OF PRIMARY BRANCHES Number of primary branches in the tree
ANGLE OF PRIMARY BRANCHES Average angle of primary branches in the tree
FRACTIONAL GROUND COVER (%) Description of the ground cover as a fraction of total area
UNDERSTORY HEIGHT (M) Height of the understory vegetation

Note: The value NaN indicates missing data, or Not a Number.

The measurements of the representative tree of each site are stored in their own files named as follows:

SV12VF_SMAPVEX_Forest_F1_intensive sampling_final_8Jan.xlsx
SV12VF_SMAPVEX_Forest_F2_intensive sampling_final_8Jan.xlsx 
SV12VF_SMAPVEX_Forest_F3_intensive sampling_final_8Jan.xlsx 
SV12VF_SMAPVEX_Forest_F5_intensive sampling_final_8Jan.xlsx

Most of the files contain worksheets for (1) general information regarding the tree, (2) the diameter and water content of the tree, (3) primary branch information, (4) secondary branch information, and (5) leaf water content information.

Table 2. Sheet 1: General Information
Data Field Description
Date Date of the sample
Site ID ID of the site
DBH Diameter at breast height of the tree
Estimated tree trunk Height of the trunk of the tree
Canopy height Height of the canopy from the first live branch
Lat. Latitude coordinate of the tree
Long. Longitude coordinate of the tree
Table 3. Sheet 2: Diameter and Water Content of the Trunk
Data Field Description
Point ID ID of the sampling (cutting) location (starting from the DBH measurement location)
Trunk Height (m) Height of the sampling (cutting) location
Trunk Diameter (inch) Diameter at the sampling (cutting) location in inches
Trunk Diameter (m) Diameter at the sampling (cutting) location in meters
Cookie Wet Mass with Bag (kg) Total mass of the about 3 cm thick wafer (cookie)
Cookie Dry Mass (kg) Dry mass of the sample wafer
Cookie Water Mass (kg) Water content of the sample wafer
Cookie Dim1 (cm) Thickness of the sample wafer
Cookie Dim2 (cm) Thickness of the sample wafer
Cookie Dim3 (cm) Thickness of the sample wafer
Cookie Dim4 (cm) Thickness of the sample wafer
Average Cookie Height (m, mm) Average thickness of the sample wafer
Cookie Volume (m^3) Volume of the sample wafer
Table 4. Sheet 3: Primary Branch Information
Data Field Description
Primary Branches ID of the primary branch
Length (inch) Length of the primary branch
Diameter (inch) Diameter of the primary branch
Angle off trunk (deg) Angle of the primary branch with respect to the trunk
# of second order Number of second order branches in the primary branch
# of third order Number of third order branches in the primary branch
Table 5. Sheet 4: Secondary Branch Information
Data Field Description
Primary #<N> ID of the secondary branch in the primary branch <N>
Length (inch) Length of the secondary branch
Diameter (inch) Diameter of the secondary branch
Angle off Primary Angle of the secondary branch with respect to the primary branch
Table 6. Sheet 5: Leaf Water Content Information
Data Field Description
Site ID ID of the site
Sample ID ID of the sample
Description Description of the sample
Wet Weight with Bag (kg) Total mass of the leaves (including the bag)
Dry Weight plus Bag (kg) Dry weight of the leaves (including the bag)
Bag Weight (kg) Weight of the bag
Dry Weight (kg) Dry weight of the leaves
Water Mass (kg) Water content of the leaves
Table 7. Latitude and Longitude Data File Columns for Field_Sites_ver4_coords.txt
Data Field Description
OBJECTID ID of the data record
Site_ID ID of the field and the sample point within the field
X UTM X coordinate
Y UTM Y coordinate
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File Size

The data files range in size from approximately 30 to 100 KB.

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Spatial Coverage

Southernmost Latitude: 49.44°N
Northernmost Latitude: 49.96°N
Westernmost Longitude: 98.51°W
Easternmost Longitude: 97.85°W

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Spatial Resolution

In situ measurements were sampled every 10 m.

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Projection Description

Data are provided in Universal Transverse Mercator (UTM) World Geodetic System 1984 (WGS84) coordinates. The locations of the Site IDs are provided in theField_Sites_ver4_coords.txt file and are given in UTM. The location of the intensive sampling is given in latitude/longitude.

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Temporal Coverage

In situ samples and measurements were collected periodically from 07 June through 17 July 2012.

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Parameter or Variable

The parameters included in this data set are:

Tree height: Total height of a tree [m]
Trunk height: Height of the trunk [m]
Canopy height: Height of the canopy measured from the first live branch [m]
Understory height: Height of the forest understory [m]
Diameter at breast height (DBH): Trunk diameter at the height of 1.3 m [inch or m]
Number of branches: Count of primary, secondary or tertiary branches [-]
Angle of branches: Angle of branches with respect to trunk or primary branch [deg]
Length of branches: [inch]
Weight: Weight of leaves or trunk wafers, before or after drying, with or without sample-holding bag [kg]
Thickness: Trunk wafer thickness [cm or m]
Volume: Trunk wafer volume [m^3]

Parameter Range

The valid parameter values are as follows:

Tree height: 0 – 30 m
Trunk height: 0 – 30 m
Canopy height: 0 – 30 m
Understory height: 0 – 2 m
Diameter at breast height (DBH): 0 – 20 in or 0 – 0.5 m
Number of branches: 0 – 100
Angle of branches: 0 – 180 deg
Length of branches: 0 – 300 in
Weight: 0 – 5 kg
Thickness: 0 – 0.1 m
Volume: 0 – 0.01 m^3

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Software and Tools

No special tools are required to view these data. A spreadsheet program such as Microsoft Excel is recommended.

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Data Acquisition and Processing

SMAPVEX12 forest vegetation sampling was divided into three parts: (1) spatial sampling, (2) destructive sampling, and (3) dielectric constant measurements. The spatial sampling took place 07 June to 28 June, and the destructive sampling and dielectric measurements occurred 29 June to 17 July.

Spatial sampling involved recording and flagging every tree with a diameter at breast height (DBH) of more than 1 inch (2.54 cm) within +/- 1 meter of the transect line. This was done for both transects within an observation area. For each tree, the following parameters were measured:

  • DBH in inches;
  • Height in meters; and
  • Species

The DBH was measured with a DBH tape at breast height. The height was recorded with a hypsometer. While standing more than 10 meters away from the tree, two measurements were taken with the hypsometer: distance to base of tree and distance to top of tree. The hypsometer then displays the total height. This is a standard technique to measure tree heights, but posed a challenge in denser forests such as F2, F3 and F5 since there was a dense understory preventing line of sight measurements. The tree species was recorded by consulting a standard tree field guide, in this case "Trees in Canada" by John L. Farrar.

The spatial sampling measurements allowed better understanding of the denser forest sites covered in this campaign. Measurements such as forest density, tree height, DBH, tree species, as well as detailed information about branches and understory, are essential to successfully parameterize radar backscattering models. At every 10 meters along the transect the GPS coordinates and more detailed parameters were recorded, including:

  • Trunk height in meters;
  • Number of primary branches;
  • Angle of primary branches;
  • Fractional ground cover in percent; and
  • Understory height in meters.

These measurements were generally taken on the tree at the 10 m point closest to the transect line. Trunk height was recorded with the hypsometer or a yard stick. The number and angle of primary branches were recorded based on visual inspection. The fractional ground cover and understory height were measured by laying down a quadrat in a representative area close to the 10 m point and recording the values based on visual inspection or by using a yard stick for the height. Destructive sampling involves harvesting an "average" tree for intensive destructive measurements. One "average" tree per field was felled using a chainsaw and the following parameters were measured:

  • Trunk diameter at each 30 cm interval;
  • Wafer of approximately 3 cm thickness for gravimetric measurements at each 30 cm interval;
  • Primary branch angles;
  • Number of branches (primary, secondary) and leaf count;
  • All branch lengths, diameters, and when possible, dielectric constant;
  • 3-4 samples of branches for gravimetric measurements; and
  • Note on leaf clumping.

At the time of destructive sampling, the spatial information was not processed. The "average" tree was selected based on visual inspection of diameter and height compared to other trees in the forest. Along with the spatial sampling information, these parameters are essential in the electromagnetic modeling of forests. Trunks and branches are modeled as cylinders with the same properties (diameters, length, dielectric, branch angle, etc.) as the average tree in the site. The measurements above provide the distributions needed to do such modeling.

See more details in sections 1.1 and 2.1.3 of the SMAPVEX12 Database Report, released 18 December 2012.

Quality Assessment

In general, the quality of the data meets the typical quality expected from this type of field campaign with the given sampling strategy. See details of the sampling approach in section 2.2.3 of the SMAPVEX12 Database Report, released 18 December 2012.

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Contacts and Acknowledgments

Mahta Moghaddam
Department of Electrical Engineering
University of Southern California
3737 Watt Way
Los Angeles, CA 90089 USA
phone: (213) 740-4712


Agriculture and Agri-Food Canada, National Aeronautics and Space Administration, U.S. Department of Agriculture, Environment Canada, U. Manitoba, U. Guelph, Massachusetts Institute of Technology, U. South Carolina, U. Colorado, U. Sherbrooke, Ohio State, U. Montana, Florida International U., U. Southern California, Texas A&M, Georgia Institute of Technology, U. Washington are acknowledged for their support for the campaign.

Document Information


August 2014



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