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Wood-decay fungus
A wood-decay or xylophagous fungus is any species of fungus that digests moist wood, causing it to rot. Some species of wood-decay fungi attack dead wood, such as Serpula lacrymans, and some, such as Armillaria (honey fungus), are parasitic and colonize living trees. Excessive moisture above the fibre saturation point in wood is required for fungal colonization and proliferation. In nature, this process causes the breakdown of complex molecules and leads to the return of nutrients to the soil. Wood-decay fungi consume wood in various ways; for example, some attack the carbohydrates in wood, and some others decay lignin. The rate of decay of wooden materials in various climates can be estimated by empirical models.
Wood-decay fungi can be classified according to the type of decay that they cause. The best-known types are brown rot, soft rot, and white rot. Each produce different enzymes, can degrade different plant materials, and can colonise different environmental niches. Brown rot and soft rot both digest a tree's cellulose and hemicellulose but not its lignin; white rot digests lignin as well. The residual products of decomposition from fungal action have variable pH, solubility and redox potentials. Over time this residue becomes incorporated in the soil and sediment so can have a noticeable effect on the environment of that area.
Wood decay fungi are considered key species in the forest ecosystems because the process of decomposing dead wood creates new habitats for other species, helps in the nutrient recycling, participate in the energy transportation and transformation and provides food to other species. They are also used as indicator species for conservation projects.
Wood decay fungi are dependent on wood. Due to forestry, cutting trees and removal of decaying wood, many species are classified as threatened.
Brown-rot fungi break down hemicellulose and cellulose that form the wood structure. Cellulose is broken down by hydrogen peroxide (H2O2) that is produced during the breakdown of hemicellulose. Because hydrogen peroxide is a small molecule, it can diffuse rapidly through the wood, leading to a decay that is not confined to the direct surroundings of the fungal hyphae. As a result of this type of decay, the wood shrinks, shows a brown discoloration, and cracks into roughly cubical pieces, a phenomenon termed cubical fracture. The fungi of certain types remove cellulose compounds from wood, and hence the wood turns brown.[citation needed]
Brown rot in a dry, crumbly condition is sometimes incorrectly referred to as dry rot in general. The term brown rot replaced the general use of the term dry rot, as wood must be damp to decay, although it may become dry later. Dry rot is a generic name for certain species of brown-rot fungi. Brown-rot fungi of particular economic importance include Serpula lacrymans (true dry rot), Fibroporia vaillantii (mine fungus), and Coniophora puteana (cellar fungus), which may attack timber in buildings. Other brown-rot fungi include the sulfur shelf, Phaeolus schweinitzii, and Fomitopsis pinicola.
Brown-rot fungal decay is characterised by extensive demethylation of lignins whereas white-rot tends to produce low yields of molecules with demethylated functional groups. There are very few brown rot fungi in tropical climates or in southern temperate zones. Most brown rot fungi have a geographical range north of the Tropic of Cancer (23.5° latitude), and most of these are found north of the 35° latitude, corresponding to a roughly boreal distribution. Those brown rot fungi between latitudes 23.5° and 35° are typically found at high elevations in pine forest regions, or in coniferous forest regions such as the Rocky Mountains or the Himalayas.
Soft-rot fungi secrete cellulase from their hyphae, an enzyme that breaks down cellulose in wood. This leads to the formation of microscopic cavities inside the wood and, sometimes, to a discoloration and cracking-pattern, similar to brown rot. Soft-rot fungi need fixed nitrogen in order to synthesize enzymes, which they obtain either from the wood or from the environment. Examples of soft-rot-causing fungi are Chaetomium, Ceratocystis, and Kretzschmaria deusta.[citation needed]
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Wood-decay fungus AI simulator
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Wood-decay fungus
A wood-decay or xylophagous fungus is any species of fungus that digests moist wood, causing it to rot. Some species of wood-decay fungi attack dead wood, such as Serpula lacrymans, and some, such as Armillaria (honey fungus), are parasitic and colonize living trees. Excessive moisture above the fibre saturation point in wood is required for fungal colonization and proliferation. In nature, this process causes the breakdown of complex molecules and leads to the return of nutrients to the soil. Wood-decay fungi consume wood in various ways; for example, some attack the carbohydrates in wood, and some others decay lignin. The rate of decay of wooden materials in various climates can be estimated by empirical models.
Wood-decay fungi can be classified according to the type of decay that they cause. The best-known types are brown rot, soft rot, and white rot. Each produce different enzymes, can degrade different plant materials, and can colonise different environmental niches. Brown rot and soft rot both digest a tree's cellulose and hemicellulose but not its lignin; white rot digests lignin as well. The residual products of decomposition from fungal action have variable pH, solubility and redox potentials. Over time this residue becomes incorporated in the soil and sediment so can have a noticeable effect on the environment of that area.
Wood decay fungi are considered key species in the forest ecosystems because the process of decomposing dead wood creates new habitats for other species, helps in the nutrient recycling, participate in the energy transportation and transformation and provides food to other species. They are also used as indicator species for conservation projects.
Wood decay fungi are dependent on wood. Due to forestry, cutting trees and removal of decaying wood, many species are classified as threatened.
Brown-rot fungi break down hemicellulose and cellulose that form the wood structure. Cellulose is broken down by hydrogen peroxide (H2O2) that is produced during the breakdown of hemicellulose. Because hydrogen peroxide is a small molecule, it can diffuse rapidly through the wood, leading to a decay that is not confined to the direct surroundings of the fungal hyphae. As a result of this type of decay, the wood shrinks, shows a brown discoloration, and cracks into roughly cubical pieces, a phenomenon termed cubical fracture. The fungi of certain types remove cellulose compounds from wood, and hence the wood turns brown.[citation needed]
Brown rot in a dry, crumbly condition is sometimes incorrectly referred to as dry rot in general. The term brown rot replaced the general use of the term dry rot, as wood must be damp to decay, although it may become dry later. Dry rot is a generic name for certain species of brown-rot fungi. Brown-rot fungi of particular economic importance include Serpula lacrymans (true dry rot), Fibroporia vaillantii (mine fungus), and Coniophora puteana (cellar fungus), which may attack timber in buildings. Other brown-rot fungi include the sulfur shelf, Phaeolus schweinitzii, and Fomitopsis pinicola.
Brown-rot fungal decay is characterised by extensive demethylation of lignins whereas white-rot tends to produce low yields of molecules with demethylated functional groups. There are very few brown rot fungi in tropical climates or in southern temperate zones. Most brown rot fungi have a geographical range north of the Tropic of Cancer (23.5° latitude), and most of these are found north of the 35° latitude, corresponding to a roughly boreal distribution. Those brown rot fungi between latitudes 23.5° and 35° are typically found at high elevations in pine forest regions, or in coniferous forest regions such as the Rocky Mountains or the Himalayas.
Soft-rot fungi secrete cellulase from their hyphae, an enzyme that breaks down cellulose in wood. This leads to the formation of microscopic cavities inside the wood and, sometimes, to a discoloration and cracking-pattern, similar to brown rot. Soft-rot fungi need fixed nitrogen in order to synthesize enzymes, which they obtain either from the wood or from the environment. Examples of soft-rot-causing fungi are Chaetomium, Ceratocystis, and Kretzschmaria deusta.[citation needed]