Plant the grass on the patch
grass3D(grass = NULL, kind = NULL, offset = c(0, 0, 0), col = "green",
opacity.threshold = c(0.2, 2), height.scale = 0.1)
vegetation data.frame
so far only a hexagon is allowed (TriangBody)
the patch offset
the color to use for grass
no grass is drawn below the lower values of LAI and full opacity is used above the upper value
scale the LAI by this factor as height for the hexagon.