Chapter 15 Wetlands 363 Copyright Goodheart-Willcox Co., Inc. Most of the vegetation in peat is still identifi able because the lack of oxygen prevents microorganisms from completely decomposing the plant matter. Muck is also formed with decomposed vegetation, but much more of the veg- etation is decomposed and the substrate closely resembles true topsoil. Histosols are divided into several categories based in part on the amount of fully-decomposed material they contain. The three main categories are saprists, hemists, and fi brists. • Saprist (muck) soils are soils in which two-thirds of the soil material is highly decomposed. Muck is often black and slimy to the touch. • Hemist (peat and muck) soils are soils in which one-half of the soil material is highly decomposed. • Fibrist (peat soil) soils are soils in which only one-third of the material is highly decomposed. Fibrist soils spend at least half of each year above water, resulting in a lower density of decaying plant matter. Many organic wetland soils are found in the Northern Hemisphere due to the climate and seasonal changes. The warm summer tempera- tures allow plant growth, but the lower fall and winter temperatures prevent complete decom- position of the dying vegetation. Organic wetland soils are valuable materials used in the horticultural and agricultural indus- tries. Peat, for example, is used for fuel, potting soil mixtures, litter, and packing vegetation for shipping, Figure 15-6. Muck can also be dried and processed for potting soil mixtures. Muck is also desirable for cultivating sod (turf). The nature of the soil allows the turf to be easily peeled and rolled. However, soil (dried muck) is removed with each layer of sod and the fi eld gets lower and wetter with each harvest. These soils also dry quickly and are highly susceptible to erosion. Wetland Classifi cations There are many organizations that have created recognized systems of wetland classifi cation. Some organizations add subclasses to existing systems to describe specifi c wetlands in more detail and others use abbreviated forms. Recognized classifi cation systems include the following: • Classifi cation of Wetlands and Deepwater Habitats of the United States (Cowardin, et al.) • Hydrogeomorphic Classifi cation for Wetlands (Brinson) • Ramsar Classifi cation System for Wetland Types (Ramsar Convention) • Coastal and Marine Ecological Classifi cation Standard (CMECS) (NOAA) Christopher Hart Krizek Vaclav/Shutterstock.com Figure 15-6. When peat is examined closely, the partially decomposed materials are visible. In some areas of the world, peat is still a common source of fuel. As it is harvested, the peat is cut into bricks and left to dry.