What do the different colors in a color-infrared aerial photograph represent?

Color-infrared (CIR) aerial photography--often called "false color" photography because it renders the scene in colors not normally seen by the human eye--is widely used for interpretation of natural resources. Atmospheric haze does not interfere with the acquisition of the image.

• Live vegetation is almost always associated with red tones. Very intense reds indicate dense, vigorously growing vegetation. As plant vigor decreases, the vegetation appears as lighter shades of red and pink, various shades of greens, and possibly tans. 
• Bare soils appear as shades of white, blue, or green in most agricultural regions. In general, darker shades of each color indicate moister soil.
• Man-made features appear in tones that relate to the materials with which they are made. Asphalt roads, for example, are dark blue or black; gravel or dirt roads are lighter colors depending on their composition; and clean concrete roads are light in tone. The colors of buildings are similarly dependent on the materials used to create them.
• Water appears as shades of blue, varying from nearly black (clean, clean water) to very pale blue (increasing amounts of sediment). The color of very shallow water is often determined by the material present at the bottom of the water. For example, a very shallow stream with a sandy bottom will appear white due to the high level of sand reflection.

Learn more: Understanding Color-Infrared Photographs