At high drying temperatures, decomposition of the accumulated low-molecular-weight carbohydrates results in a visible darkening of the enriched zone called kiln brown stain
(KBS), which is typically found just beneath the surfaces of boards.
Kiln brown stain is a problem in ponderosa pine (Pinusponderosa) and other species of shop and appearance grade lumber.
Kiln brown stain is a problem in ponderosa pine (Pinus ponderosa) and other species of shop and appearance grade lumber.
Temperatures above 160[degrees]F (71[degrees]C) are generally believed to increase the formation of kiln brown stain. So, mild antistain schedules with temperatures mostly below 160 [degrees]F (71 [degrees]C) are commonly used to reduce kiln brown stain.
They found that kiln brown stain had been reported in many softwood and hardwood species of lumber around the world.
In research on radiata pine, it was found that kiln brown stain occurred just under (0.02 to 0.08 inches (0.5 to 2 mm)) the wood surface (Kreber et al.
concluded that kiln brown stain begins to develop at a surprisingly high MC (100%) and worsens as MC decreases (Kreber et al.
The objectives of the current investigation were to determine whether the timing (early, late, or continuous) of high kiln temperatures affected the formation of kiln brown stain in ponderosa pine shop lumber and the grade, value, and color and lightness changes in that lumber.