Pecan , Carya illinoinensis or illinoensis, is a species of hickory, native to south-central North America, in Mexico from Coahuila south to Jalisco and Veracruz, in the United States from southern Iowa, Illinois and Indiana east to western Kentucky, North Carolina, South Carolina and western Tennessee, south through Georgia, Alabama, Mississippi, Louisiana, Texas, Oklahoma, Arkansas and Florida, and west into New Mexico.
Pecan is from an Algonquian word, meaning a nut requiring a stone to crack. Spalting is any form of wood coloration caused by fungi. Although primarily found in dead trees, spalting can also occur under stressed tree conditions or even in living trees. Although spalting can cause weight loss and strength loss in the wood, the unique coloration and patterns of spalted wood are sought after by woodworkers
Spalting in hardwoods is divided into three main types: pigmentation, white rot and zone lines. Spalted wood may exhibit one or all of these types in varying degrees. Softwoods are susceptible to brown rot which degrades the wood too quickly to be used for woodworking.
Pigmentation Also known as sapstain, or in its most common form, bluestain, this type of spalting occurs when the darkly-pigmented fungal hyphae grow in the sapwood parenchyma of a tree. A visible color change can be seen if enough hyphae are concentrated in an area. These pigmentation fungi often colonize wood via the rays, but are not considered decay fungi due to their non-destructive use of easily available wood carbohydrates. The most common groups of pigmentation fungi are the imperfect fungi and the Ascomycetes. Mold fungi, such as Trichoderma spp., are not considered to be spalting fungi, as their hyphae do not colonize the wood internally.
While pigmentation fungi do not degrade the wood cell wall, this type of decay can lead to a reduction in toughness (amount of energy absorbed before breaking), and increased permeability. Pigmentation can occur on both hardwood and softwood, unlike other types of spalting which are more host specific. White Rot The mottled white pockets and bleaching effect seen in spalted wood is due to white rot fungi. Primarily found on hardwoods, these fungi 'bleach' by consuming lignin, which is the slightly pigmented area of a wood cell wall. Some white rotting can also be caused by an effect similar to pigmentation, in which the white hyphae of a fungus, such as Trametes versicolor (Fr.) Pil., is so concentrated in an area that a visual effect is created.
Both strength and weight loss occur with white rot decay, causing the 'punky' area often referred to by woodworkers. Brown rots, the 'unpleasing' type of spalting, affect these same properties, but at a much faster rate. Both types of rot, if left uncontrolled, will turn wood useless. Zone Lines Dark dotting, winding lines and thin streaks of red, brown and black are known as zone lines. This type of spalting does not occur due to any specific type of fungus, but is instead an interaction zone in which different fungi have erected barriers to protect their resources. The lines are often clumps of hard, dark mycelium, referred to as pseudosclerotial plate formation.
Zone lines themselves do not damage the wood. However, the fungi responsible for creating them often do. Conditions required for spalting are the same as the conditions required for fungal growth: fixed nitrogen, micronutrients, water, warm temperatures and oxygen.
Water: Wood must be saturated to a 20% moisture content or higher for fungal colonization to occur. However wood placed underwater lacks sufficient oxygen, and colonization cannot occur.
Temperature: The majority of fungi prefer warm temperatures between 10 and 40°C, with rapid growth occurring between 20 and 32°C. Oxygen: Fungi do not require much oxygen, but conditions such as water logging will inhibit growth.
Time: Different fungi require different amounts of time to colonize wood.
Pecan is from an Algonquian word, meaning a nut requiring a stone to crack. Spalting is any form of wood coloration caused by fungi. Although primarily found in dead trees, spalting can also occur under stressed tree conditions or even in living trees. Although spalting can cause weight loss and strength loss in the wood, the unique coloration and patterns of spalted wood are sought after by woodworkers
Spalting in hardwoods is divided into three main types: pigmentation, white rot and zone lines. Spalted wood may exhibit one or all of these types in varying degrees. Softwoods are susceptible to brown rot which degrades the wood too quickly to be used for woodworking.
Pigmentation Also known as sapstain, or in its most common form, bluestain, this type of spalting occurs when the darkly-pigmented fungal hyphae grow in the sapwood parenchyma of a tree. A visible color change can be seen if enough hyphae are concentrated in an area. These pigmentation fungi often colonize wood via the rays, but are not considered decay fungi due to their non-destructive use of easily available wood carbohydrates. The most common groups of pigmentation fungi are the imperfect fungi and the Ascomycetes. Mold fungi, such as Trichoderma spp., are not considered to be spalting fungi, as their hyphae do not colonize the wood internally.
While pigmentation fungi do not degrade the wood cell wall, this type of decay can lead to a reduction in toughness (amount of energy absorbed before breaking), and increased permeability. Pigmentation can occur on both hardwood and softwood, unlike other types of spalting which are more host specific. White Rot The mottled white pockets and bleaching effect seen in spalted wood is due to white rot fungi. Primarily found on hardwoods, these fungi 'bleach' by consuming lignin, which is the slightly pigmented area of a wood cell wall. Some white rotting can also be caused by an effect similar to pigmentation, in which the white hyphae of a fungus, such as Trametes versicolor (Fr.) Pil., is so concentrated in an area that a visual effect is created.
Both strength and weight loss occur with white rot decay, causing the 'punky' area often referred to by woodworkers. Brown rots, the 'unpleasing' type of spalting, affect these same properties, but at a much faster rate. Both types of rot, if left uncontrolled, will turn wood useless. Zone Lines Dark dotting, winding lines and thin streaks of red, brown and black are known as zone lines. This type of spalting does not occur due to any specific type of fungus, but is instead an interaction zone in which different fungi have erected barriers to protect their resources. The lines are often clumps of hard, dark mycelium, referred to as pseudosclerotial plate formation.
Zone lines themselves do not damage the wood. However, the fungi responsible for creating them often do. Conditions required for spalting are the same as the conditions required for fungal growth: fixed nitrogen, micronutrients, water, warm temperatures and oxygen.
Water: Wood must be saturated to a 20% moisture content or higher for fungal colonization to occur. However wood placed underwater lacks sufficient oxygen, and colonization cannot occur.
Temperature: The majority of fungi prefer warm temperatures between 10 and 40°C, with rapid growth occurring between 20 and 32°C. Oxygen: Fungi do not require much oxygen, but conditions such as water logging will inhibit growth.
Time: Different fungi require different amounts of time to colonize wood.