This data set contains the vegetation parameters plant height, row spacing, stand density, and leaf area index (LAI) as part of the Soil Moisture Experiment 2002 (SMEX02). The SMEX studies are designed to evaluate, among other things, the accuracy of AMSR-E soil moisture data. This study was conducted during June and July 2002 in the SMEX02 Iowa regional area around Ames, Iowa, USA. LAI was ... measured by a plant canopy analyzer. The other parameters were measured manually. Leaf area index (LAI) is the ratio of the total area of all leaves on a plant to the area of ground covered by the plant. Stand density is the number of plants in a meter length of a crop row. Plant height and row spacing data are given in meters. Data are provided in ASCII text files and are available via FTP. These data were collected as part of a validation study for the Advanced Microwave Scanning Radiometer - Earth Observing System (AMSR-E). AMSR-E is a mission instrument launched aboard NASA's Aqua Satellite on 04 May 2002. AMSR-E validation studies linked to SMEX are designed to evaluate the accuracy of AMSR-E soil moisture data. Specific validation objectives include assessing and refining soil moisture algorithm performance; verifying soil moisture estimation accuracy; investigating the effects of vegetation, surface temperature, topography, and soil texture on soil moisture accuracy; and determining the regions that are useful for AMSR-E soil moisture measurements.