Wood Wise Words from the World of Wood

Under proper conditions, wood will give centuries of service. However, under conditions that permit the development of wood-degrading organisms, protection must be provided during processing, merchandising, and use. Organisms that can degrade wood are typically fungi, insects, bacteria, and marine borers.

This Wood Wise series is dedicated specifically to decay, the decomposition of wood substances by fungi.

Advanced (Typical) Decay: The older stage of decay in which the destruction is readily recognized because the wood has become punky, soft and spongy, stringy, ringshaked, pitted, or crumbly. Decided discoloration or bleaching of the rotted wood is often apparent.

Brown Rot: In wood, any decay in which the attack concentrates on the cellulose and associated carbohydrates rather than on the lignin, producing a light to dark brown friable residue—hence loosely termed “dry rot.” An advanced stage where the wood splits along rectangular planes, in shrinking, is termed “cubical rot.”

Dry Rot: A term loosely applied to any dry, crumbly rot but especially to that which, when in an advanced stage, permits the wood to be crushed easily to a dry powder. The term is actually a misnomer for any decay, since all fungi require considerable moisture for growth.

Incipient Decay: The early stage of decay that has not proceeded far enough to soften or otherwise perceptibly impair the hardness of the wood. It is usually accompanied by a slight discoloration or bleaching of the wood.

Heart Rot: Any rot characteristically confined to the heartwood. It generally originates in the living tree.

Pocket Rot: Advanced decay that appears in the form of a hole or pocket, usually surrounded by apparently sound wood.

Soft Rot: A special type of decay developing under very wet conditions (as in cooling towers and boat timbers) in the outer wood layers, caused by cellulose?destroying microfungi that attack the secondary cell walls and not the intercellular layer.

White?Rot: In wood, any decay or rot attacking both the cellulose and the lignin, producing a generally whitish residue that may be spongy or stringy rot, or occur as pocket rot.

From the Wood Handbook: Wood as an Engineering Material, FPL–GTR–190.

Wood Wise Words from the World of Wood

To acknowledge the hard work and dedication of our Forest Service colleagues during the challenging 2012 fire season, this edition of Wood Wise includes words from the world of wildfire.

Although a connection to forest products and wildfire may seem tenuous, thinning overgrown forests to remove dense undergrowth helps reduce the threat of catastrophic wildfire. Thinnings can also be used for various value-added products. Using excess material for bioenergy purposes, composite materials, and even nanotechnology can help create jobs and improve the economy of thinning projects. For example, treating 123,000 acres in fiscal year 2011 contributed $21 million to local economies across the United States.

Backfire: A fire set along the inner edge of a fireline to consume the fuel in the path of a wildfire or change the direction of force of the fire’s convection column. Synonym: Burn Out.

Convection Column: The rising column of gases, smoke, fly ash, particulates, and other debris produced by a fire. The column has a strong vertical component indicating that buoyant forces override the ambient surface wind. Synonym: Smoke Plume.

Daily Activity Level: In fire danger rating, a subjective estimate of the degree of activity of a potential human-caused fire source relative to that which is normally experienced. Fire activity levels are defined as None, Low, Normal, High, and Extreme. Part of the National Fire Danger Rating System.

Fire Front: The part of a fire where continuous flaming combustion is occurring. Unless otherwise specified, the fire front is assumed to be the leading edge of the fire perimeter.

Fireline: The part of a containment or control line that is scraped or dug to mineral soil.

Pulaski: A combination chopping and trenching tool widely used in fireline construction, which combines a single-bitted axe blade with a narrow adze-like trenching blade fitted to a straight handle.

Wildfire: An unplanned, unwanted wildland fire including unauthorized human-caused fires, escaped wildland fire use events, escaped prescribed fire projects, and all other fires where the objective is to put the fire out. Synonyms: Uncontrolled Fire, Wildland Fire

Adapted from the National Wildfire Coordinating Group glossary of wildland fire terminology.

Wood Wise Words from the World of Wood

Adhesive: A substance capable of holding materials together by surface attachment. It is a general term and includes cements, mucilage, and paste, as well as glue.

Cold?Setting Adhesive: An adhesive that sets at temperatures below 20 °C (68 °F).

Hot?Setting Adhesive: An adhesive that requires a temperature at or above 100 °C (212 °F) for it to set.

Room?Temperature-Curing Adhesive: An adhesive that sets in the temperature range of 20 to 30 °C (68 to 86 °F), in accordance with the limits for Standard Room Temperature specified in the Standard Methods of Conditioning Plastics and Electrical Insulating Materials for Testing (ASTM D 618).

For more on adhesives used with wood check out our 2010 Wood Handbook— Wood as an Engineering Material.

Wood Wise Words from the World of Wood

Nanometer: A distance unit representing one-billionth of a meter, or one-millionth of a millimeter – roughly one-millionth the thickness of an American dime.

Nanotechnology: A collective term referring to the manipulation and control of materials at the nanometer scale. Physical phenomena are found at this microscopic scale that differs from those operating at the macroscopic scale.

Nanoscale: A size range from 1 to 100 nanometers, where many of the fundamental structures of biology are formed and where composite materials may take on distinctive characteristics.

Nanocomposite: A material composed of two or more substances, of which at least one has a nanoscale dimension, such as nanoparticles dispersed throughout another solid material.

Nanocellulose: Also called microfibrillated cellulose, this microscopic material is composed of nanoscale cellulose fibrils with a high length to width ratio. Typical dimensions are 5- 20 nanometers in width and length up to 2000 nanometers.

For more on nanotechnology, visit www.nano.gov.