Why does wood change color(2)
2.Mildew discoloration of wood
Mildew can discolor the surface and sapwood of the wood, but the discoloration of mildew is lighter, and the discoloration is caused by colored spores. Since the mold spores only multiply and grow on the surface of the wood, the mold of the wood is limited to the surface of the wood or a very shallow layer near the surface.
Mildew often renders wood green, white, black, and occasionally other colors. Discoloration caused by mold is often flocculent or speckled. In warm and humid climates, or in poorly ventilated environments, mold spores deposited on wood surfaces can easily multiply and grow mold.
Wood mold fungi include Trichoderma, Penicillium, Aspergillus, Mucor and so on.
The most important of the Trichoderma fungi is Trichoderma viride, the surface of wood infected with this fungus is green. There are many species of Penicillium and Aspergillus, the most common one is Aspergillus niger. After the wood is infected with this mold, the surface appears black spots, sometimes connected into pieces. The adaptability and tolerance of mold to the environment and substrates are stronger than that of blue-mutant bacteria and decay bacteria. Mildew can still be found on some preserved wood.
Since the result of wood mildew is only to discolor the wood surface, and the range of discoloration is shallow, it can be removed with a brush or by planing off the surface layer. Mildew has little effect on the quality of the wood itself and, therefore, is generally not considered a defect.
However, after the mold infects the wood, it can increase the permeability of the liquid to the wood, which can promote the formation of blue stain.
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