When the Landsat 4 satellite passed over West Virginia just before noon yesterday, it took pictures of Lost River, the early autumn foliage and four acres of black-and-white plastic placed side by side by 13 Hardy County high school students.

The 90 sheets of 20-by-100-foot plastic in a West Virginia cornfield were there for more reasons than a high school project. They were helping Landsat scientists calibrate a new instrument, a "thematic mapper," helping solve the mystery of the Lost River's natural gas deposits, and helping to explain the region's strange abundance of red maple trees.

"There's no good botanical reason why maples are at this particular site," said Dr. Barry Rock of California's Jet Propulsion Laboratory. "Maples are tolerant of harsh soil conditions and may be growing over leaking . . . reserves of natural gas that would discourage the growth of other trees."

Rock and four other scientists from JPL have been studying the geology of West Virginia's Lost River for the last four years in preparation for the launch of Landsat 4, which was put into orbit July 16 by NASA.

On board this Landsat is the new thematic mapper camera whose seven lenses take pictures in seven wavelengths ranging through all colors of visible light and through three regions of invisible infrared light.

Landsat's photos of the plastic target will be used by JPL, which built the camera, to construct a color scale ranging from black to white with 254 shades of gray in between. The photos of autumn foliage will be used to compare exaggerated color differences; infrared photos of the plastic will show temperature changes.

"The black plastic sheets should show up very hot on the infrared because black retains heat," said JPL's Dr. Anne Kahle. "The white sheets will show up cold because they reflect heat."

One of the main purposes of the Lost River exercise is to determine if there's a connection between the hidden natural gas reserves along the river and the surface rocks, soil and foliage.

Maps made from the air show an odd distribution of maple trees along the river. While oak, evergreen and hickory trees dominate the region, isolated stands of maples appear in all the maps.

"Red maples will grow in areas with anaerobic non-oxygenated soil similar to soils containing methane," Rock said. "If you had to pick a locally occurring tree that would grow in methane-saturated soil, it would be red maple."