Peat is vegetable matter which has been partially carbonized due to the way in which it decomposes. Over time, peat deposits have the potential to evolve into coal. There are a number of uses for it, although the two primary ones are as a type of fuel and as a fertilizer. Many countries exploit and sell their peat resources, especially Ireland, Scotland, and Finland. In these nations, blocks are readily available as a fuel source, and it is also sold in less compacted form for gardeners.
The process of peat formation is very slow. Moss is one of the primary components, although it may also contain other plant matter such as grasses and shrubs. In addition, peat often contains decomposing material of animal origin. In order for the material to form, conditions must be wet, acidic, and cold. As a result, peat forms most often in bogs and marshes, which are wet with poor drainage, promoting its formation.
The cold and acidity keep decomposition rates slow. It can take hundreds or thousands of years for a deposit to build up, as layers of new plant material grow on top of layers of decomposing peat. Many cultures associated peat bogs with spirits or gods, and traces of sacrifices can be found in bogs in many parts of the world. Tollund Man, for example, is believed to have been a sacrificial offering to a peat bog. The highly acidic conditions of these bogs have preserved some of these victims remarkably well, allowing archaeologists to learn more about the periods in which they lived.
When peat is harvested, it is cut out of the bog in long strips which are compressed and dried. Harvesting has put bogs all over the world in danger, as it can be collected much more rapidly than it will be replenished, creating a dramatic change in the natural environment of the bog. Once compressed, the peat may be fired as fuel, mixed into gardens to retain moisture and promote nutrient retention, or used to create biodegradable planters for plants. It can also be used to make paper, pad livestock beds, or pack products for shipment.
In some countries with large peat deposits, steps have been taken to keep harvesting sustainable. There are also some concerns about it as a fire risk, since it can smolder for days, even underground, emitting noxious fumes and pollutants all the while. For construction crews, peat can be extremely irritating, because it is easily compressed. This means that it cannot bear any weight, making the bogs useless for any type of construction.