Lumber Stains: Cause and Control Lance Johnson ISK Biocides, Inc.. Memphis, TN

Lumber Stains: Cause and Control Types of Stain: –FUNGAL (Microbial) –NON-FUNGAL (Non- Microbial)

Lumber Stains: Cause and Control Types of Stain: –FUNGAL (Microbial) Mold Sapstain

Lumber Stains: Cause and Control NON-FUNGAL (Non-microbial) –Enzymatic “Gray” Stain –Sticker Stain –Iron Stain –Mineral Stain

Lumber Stains: Cause and Control Fungal (Microbial) Stain

Lumber Stains: Cause and Control A primitive plant with no stem, roots, leaves, chlorophyll. DOES have a Hypha (Hyphae) body (threadlike strands). DOES have Fruiting Structures which produce Spores (Seeds).

Lumber Stains: Cause and Control CONDITIONS FOR FUNGAL GROWTH: –Fungi must have oxygen –Temperature range of degrees F –Moisture content of 20% to saturation –Food source

Lumber Stains: Cause and Control MOLD and SAPSTAIN FUNGI: –Utilize readily available nutrients (starch, sugar, protein, and fats) stored in the sap wood (parenchyma cells)

Lumber Stains: Cause and Control MOLD FUNGI

Lumber Stains: Cause and Control MOLD FUNGI: Form SPORES of various colors on surface of wood, HYPHAE are not pigmented. Discoloration does NOT appear below surface of wood

Lumber Stains: Cause and Control SAPSTAIN FUNGI

Lumber Stains: Cause and Control SAPSTAIN FUNGI: Pigment of HYPHAE cause discoloration below the surface of the wood.

Lumber Stains: Cause and Control –Require at least 20% wood moisture content

Lumber Stains: Cause and Control –Cause little loss of wood strength

Lumber Stains: Cause and Control –Optimum temperature = degrees F

Lumber Stains: Cause and Control Fungal SPORES become air-borne and are deposited on freshly cut lumber. Growth starts very quickly These SPORES also contaminate sawmill machinery and equipment Wood debris around a mill yard provides an excellent source of fungal SPORES

Lumber Stains: Cause and Control CONTROLLING FUNGAL STAIN: –Proper Handling of raw material –Oxygen depletion –Envelope biocide treatment –Proper drying practices

Lumber Stains: Cause and Control Proper Handling of Raw Material: –Rapid utilization of logs –Short water-spray storage –First IN – First OUT –Encapsulation of logs

Lumber Stains: Cause and Control Oxygen Depletion: –Log ponding –Water sprays

Lumber Stains: Cause and Control Envelope Biocides Treatment: –Provides relatively inexpensive short- term protection by coating surface of the lumber with biocide chemical –Applied using dip or spray method –Relatively short dipping time

Lumber Stains: Cause and Control Envelope Biocide Treatment (Cont.): –Will not kill insect larvae feeding within the wood –Will not control non-microbial enzymatic “gray” stain or mineral stain

Lumber Stains: Cause and Control Biocide treatment should be applied immediately after sawing!

Lumber Stains: Cause and Control When choosing a product: –Review the toxicity package –Possibly field test at your site –Review the independent Efficacy data –Look at QC methods for wood & solution –Remember… It should be a partnership between the log supplier, the sawmill and the chemical producer to produce the best product

Lumber Stains: Cause and Control Yellow Poplar – Six Weeks in Plastic

Lumber Stains: Cause and Control Treatment Methods –Across-the-chain tank –Bulk dip tank –Spray

Lumber Stains: Cause and Control Recommendations for a Biocide Dipping Facility: –Coated, lined, or stainless steel dip tank – iron stain –Agitation – debris accumulation –Covered – rain dilution

Lumber Stains: Cause and Control More Recommendations: –Drip pad – excess biocide recovery –Tank containment

Lumber Stains: Cause and Control Chemical Safety Precautions -Follow chemical manufacturers material safety data sheet

Lumber Stains: Cause and Control Treatment of lumber with biocides is NOT a substitute for proper drying practices!

Lumber Stains: Cause and Control Good Air Drying Facility: –Well drained –No weeds or debris

Lumber Stains: Cause and Control  NON-FUNGAL (Non-Microbial) STAIN

Lumber Stains: Cause and Control  Enzymatic “Gray” Stain

Lumber Stains: Cause and Control Non-Microbial Enzymatic “Gray” Stain: –Caused by enzymatic oxidation reactions within parenchyma cells –Slow drying conditions and water storage of logs favor development

Lumber Stains: Cause and Control Control of Non-Microbial Enzymatic “Gray” Stain: –Rapid utilization of logs –Good drying facilities –Steaming or rapid heating of lumber –Diffusion treatment of lumber –Physical stressing of lumber

Lumber Stains: Cause and Control  Sticker Stain

Lumber Stains: Cause and Control Sticker Stain: Actually a Non-Microbial Enzymatic “Gray” Stain enhanced by slowed Moisture loss under sticker

Lumber Stains: Cause and Control Control of Sticker Stain : –Use dry stickers –Rapid drying of lumber –Use grooved stickers with less contact area

Lumber Stains: Cause and Control  IRON STAIN

Lumber Stains: Cause and Control Iron Stain: –Caused by reaction of wood extractives (tannins) with iron to form iron tannate on lumber

Lumber Stains: Cause and Control Iron Stain Control: –Exposure of unseasoned lumber to iron should be minimized –Uncoated mild steel dipping tanks should not be used –Add an iron stain inhibitor to your biocide chemical

Lumber Stains: Cause and Control  MINERAL STAIN Elements taken up from the soil during tree growth cause discoloration. The extent of this type of stain largely depends on soil make-up.