1. Working within an area of forested islands, no aquatic vegetation. --- The interpreter first locates then marks the land/water interface. Each island is studied to see if more than one land cover/land use type is present. If multiple types are present, the interpreter analyzes the area to see if the trees are growing in a mixture or if unique stands of trees are present. Each polygon is then labeled with the appropriate vegetation code followed by a character describing the percent of the island covered by the trees (i.e., canopy closure). The average tree height is then calculated and recorded.
2. A sand bar/dredge spoil island sparsely vegetated with grass. --- As with the previous example, the interpreter first marks the outer boundary of the sand bar. If all of the vegetation is localized within one region of the sand bar and the area is large enough to be mapped, a boundary line is drawn around the vegetation. If the vegetation is so sparse that it does not cover at least 10% of the sand surface, the grasses are ignored and the area is mapped as sand. If the grasses cover more than 10% of the sand surface, the area is mapped as grass and the percent vegetation cover is noted. Vegetation height is recorded only when trees are present.
3. A transition zone containing a mixture of various rooted and floating vegetation, emergents, and submergents. --- The area containing the mixture is first separated from its surrounding features. The mixture is then analyzed to see if the region contains a uniform mixture of plants or several distinct regions of different plant mixtures. Each polygon is labeled with the appropriate vegetation code, then the percent vegetation cover is noted.
LTRMP interpreters do not analyze plant mixtures to determine plant dominance. Therefore, the sequence in which mixed vegetation types are listed is arbitrary and does not represent plant dominance.