Paludification is the most common process by which

peatlands A mire, peatland, or quagmire is a wetland area dominated by living peat-forming plants. Mires arise because of incomplete decomposition of organic matter, usually litter from vegetation, due to water-logging and subsequent anoxia. All types ...

in the boreal zone are formed.

Formation

The process is characterized by

peat Peat (), also known as turf (), is an accumulation of partially decayed vegetation or organic matter. It is unique to natural areas called peatlands, bogs, mires, moors, or muskegs. The peatland ecosystem covers and is the most efficien ...

initialization on previously drier and vegetated habitats over inorganic soils, with no fully aquatic phase. Thus the paludification process includes a shift from

forest A forest is an area of land dominated by trees. Hundreds of definitions of forest are used throughout the world, incorporating factors such as tree density, tree height, land use, legal standing, and ecological function. The United Nations' ...

grassland A grassland is an area where the vegetation is dominated by grasses (Poaceae). However, sedge (Cyperaceae) and rush (Juncaceae) can also be found along with variable proportions of legumes, like clover, and other herbs. Grasslands occur natur ...

or long exposed bare land to peatland. The initiation of this accumulation of organic matter (i.e. peat), can be controlled by both allogenic (i.e. external to the ecosystem) and autogenic (i.e. internal to the ecosystem) factors. The

hydrological Hydrology () is the scientific study of the movement, distribution, and management of water on Earth and other planets, including the water cycle, water resources, and environmental watershed sustainability. A practitioner of hydrology is calle ...

balance is critical for the initiation of peat. The hydrological balance can simply be defined as the difference between the incoming and outgoing amount of water (e.g. precipitation minus

evapotranspiration Evapotranspiration (ET) is the combined processes by which water moves from the earth’s surface into the atmosphere. It covers both water evaporation (movement of water to the air directly from soil, canopies, and water bodies) and transpi ...

and minus runoff). Usually it is considered that factors such as climate, geomorphology,

geology Geology () is a branch of natural science concerned with Earth and other astronomical objects, the features or rocks of which it is composed, and the processes by which they change over time. Modern geology significantly overlaps all other Ear ...

and soils control this balance. However, paludification may also be just a result of the local accumulation of peat (i.e. autogenic factor).

Climatic factors

The climate factor has a great influence on the paludification process. The development of a paludified soil requires a positive hydrological balance during the growing season. Therefore, there needs to be a shift in local hydrological conditions. Such a shift could be caused by an increase in water inputs or a decrease in outputs. Human activity such as tree removal, natural or human induced

forest fire A wildfire, forest fire, bushfire, wildland fire or rural fire is an unplanned, uncontrolled and unpredictable fire in an area of Combustibility and flammability, combustible vegetation. Depending on the type of vegetation present, a wildfire ...

s, increase in

precipitation In meteorology, precipitation is any product of the condensation of atmospheric water vapor that falls under gravitational pull from clouds. The main forms of precipitation include drizzle, rain, sleet, snow, ice pellets, graupel and hail. ...

, and podsolization, etc. are processes which could change those in- and outputs.

Geomorphology

The factor geomorphology (and also topography) creates spatial diversity in the hydrological characteristics of the landscape. The flat topography (and thus low slopes) in the two major peatlands in the world, located in the

West Siberian Plain The West Siberian Plain (russian: За́падно-Сиби́рская равни́на ''Zapadno-Sibirskaya ravnina'') is a large plain that occupies the western portion of Siberia, between the Ural Mountains in the west and the Yenisei River ...

and in the Hudson/James Bay Lowlands of

Canada Canada is a country in North America. Its ten provinces and three territories extend from the Atlantic Ocean to the Pacific Ocean and northward into the Arctic Ocean, covering over , making it the world's second-largest country by tot ...

respectively, illustrate the significance of this factor.

Impact of soils

Geology and soils (i.e. bedrock and texture) play also an important role. When the mineral soil is composed of heavy clay, the soil will act as an impermeable substrate that facilitates water accumulation. Simply an increase in

surface water Surface water is water located on top of land forming terrestrial (inland) waterbodies, and may also be referred to as ''blue water'', opposed to the seawater and waterbodies like the ocean. The vast majority of surface water is produced by prec ...

from melting permafrost can cause increased paludification in boreal ecosystems. In the context of forest management, paludification has been studied intensively during the last decade. Especially because of the negative effects paludification has for the boreal forests. In this way that paludification may lead to: * Reduction in soil temperature, soil aeration, nutrient availability, decomposition rates * Formation of

permafrost Permafrost is ground that continuously remains below 0 °C (32 °F) for two or more years, located on land or under the ocean. Most common in the Northern Hemisphere, around 15% of the Northern Hemisphere or 11% of the global surface ...

in certain areas * Increase of the

water table The water table is the upper surface of the zone of saturation. The zone of saturation is where the pores and fractures of the ground are saturated with water. It can also be simply explained as the depth below which the ground is saturated. T ...

level * Decrease in tree productivity.Lavoie, M., Paré, D., Fenton, N., Taylor, K., Groot, A., and Foster, N., 2005. Paludification and forest management in the Northern Clay Section: a literature review. Lake Abitibi Model Forest Technical Report No.1. 75 p. link:

References

{{Wetlands Soil Wetlands Bogs Limnology

Formation

Climatic factors

Geomorphology

Impact of soils

See also

References