Upper story and density of soapweed (Yucca elata) in grama grass

Upper story and density of soapweed (Yucca elata) in grama grass type. There are many thousands acres of this type combination on the reserve. Jornada Range Reserve. File number 32GR72. Dona Ana County, New Mexico. United States Forest Service, Washington, D.C. Black and white images hand painted directly on glass with either transparent oil paints, aniline dyes or watercolors by colorists. Glass lantern slides were sometimes baked after painting to set paint layers.