Total cover of the tree layer in percent. Includes tall trees (single-stemmed woody plants, generally more than 5 m in height or greater at maturity under optimal growing conditions). Very tall shrubs with tree-like form may also be included here, as may other life forms, such as lianas and epiphytes.
Total cover of the shrub layer in percent. Includes shrubs (multiple-stemmed woody plants, generally less than 5 m in height at maturity under optimal growing conditions) and shorter trees (saplings). As with the tree stratum, other life forms present in this stratum may also be included (however, herbaceous life forms should be excluded, as their stems often die back annually and do not have as consistent a height as woody life forms). Where dwarf-shrubs (i.e. shrubs shorter than 0.5 m) form a distinct stratum (either as part of a series of strata, as in a forest, or as the top stratum of more open vegetation, such as tundra or xeric shrublands), they should be treated as a low version of the shrub stratum (or short shrub substratum). In many vegetation types, dwarf-shrubs may simply occur as one life form component of the herb stratum.
Total cover of the field layer in percent. Also referred to as Herb stratum. Includes herbs (plants without woody stems and often dying back annually), often in association with low creeping semi-shrubs, dwarf-shrubs, vines, and non-woody brambles (such as raspberries), as well as tree or shrub seedlings.
Total cover of the nonvascular layer in percent. Also referred to as moss, bryoid, or ground stratum. Defined entirely by mosses, lichens, liverworts, and alga. Ground-creeping vines, prostrate shrubs and herbs should be treated in the herb stratum. Where herbs are entirely absent, it is still possible to recognize this stratum if other very low woody or semi-woody life forms are present.