Blue Stain in pine board. The coloration in wood is due to the pigment in the fungal hypae.
Bowl made from blue stained pine wood. Stained wood with this dramatic blue coloration can be used to make interesting wooden items and art work.
Insects vector blue stain fungi. Above are tunnels of ambrosia beeles in wood. These beetles carry specific stain fungi and introduce them into the wood. The larvae eat the fungus while maturing in the wood.
Ambrosia beetle tunnels and blue stain fungi in maple.
Bark beeltes also vector blue stain fungi such as this mountain pine beetle.
Synnemata produced by a blue stain fungus as seen with a hand lens.
Many blue stain fungi such as species of Ophiostoma produce synnemata. These asexual structures have sticky spores that are moved around by insects.
Perithecia produced by a blue stain fungus on pine wood. Note bulbous base at each perithecium.
A perithecium with a very long neck. Asci open inside the perithecium and ascospores ooze out of the ostiole at the tip of the neck in a sticky matrix.
Since blue stain fungi only colonizes the sawood, fast growing trees like this radiata pine grown in New Zealand can be very suceptible to stain. This tree was 2 feet in diameter and only about 24 years old. If stain fungi colonized this wood, all of it would be stained.
Green stain (or blue/green) in aspen and birch caused by Chlorociboria.
Chlorociboria produces blue/green apothecia on wood.
Another type of stain that is greenish black is not caused by a fungus but a reaction of iron to the tannins in oak, cherry and other woods. This is called iron-tannic stain.
Iron tannic stain occurs in cracks in trees and surfaces that react with iron (carried in with water) are stained. The stain does not diffuse deep into the wood adjacent to the cracks.
A black stain in oak wood caused by iron. This tree had barbed wire attached to it and the tree grew around it. This also happens when nails are in trees. Oak and other trees with tannins in their heartwood react when iron is present. The stain may extend far from the actual iron wire or nail.
Red stain in box elder. This stain is produced by the tree as a host reponse.
People are often amazed to find red stain when they cut up box elder with its vivid extraordinary color.
Wood workers use the red stained wood to make interesting objects but beware the red compound is not stable and breaks down in light - as you can see above with a change from red to brown in this vase after about 6 months out in normal room lighting.
A different red stain (a dark blood red) ocurrs in pine wood. This is caused by fungal pigments produced by a decay fungus Phanerochaete sanguinea.