Stain

Stain refers to a discoloration of the wood caused by fungi, bacteria, or other microorganisms that can grow on or within the wood. These microorganisms can cause a range of colors and patterns in the wood, ranging from brown, black, or blue stains to streaks or spots.

Stain can occur in both living and dead trees, and can be caused by a variety of factors, including environmental conditions, such as temperature and moisture levels, and the presence of other organisms, such as insects or other fungi. Stain can also be caused by improper storage or handling of the wood, or by exposure to chemicals or other contaminants.

While stain in lumber is generally considered to be a cosmetic issue, it can also affect the strength and durability of the wood. Stained wood may be weaker or less durable than unstained wood, and may be more prone to cracking or splitting.