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Forest Products Laboratory
One Gifford Pinchot Drive
Madison, WI 53726-2398
Phone: (608) 231-9200
Fax: (608) 231-9592
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Wood ID Fact Sheet

Identification process:

Accurate wood identification depends mainly on characteristics of the wood cells revealed under a microscope. First, a cross-sectional surface of the sample is smoothed with a sharp knife and examined with a hand lens. Then small, thin sections are cut freehand along the grain from the radial and tangential surfaces and prepared for viewing under the microscope.

Hand lenses

Identifications are usually completed by means of technical anatomical features observed at high magnification. Gross features such as color, odor, and texture are of limited help as they can be quite variable and therefore are less reliable.

Limitations:

Identifications based on wood anatomy are generally accurate only to genus (e.g. spruce) or, in some cases, to a subgeneric grouping (e.g., white oak group), but rarely to the exact species. Therefore, all information known about the specimen is important and should be provided. The wood's common name, country, or geographic area of origin are especially useful and may help to determine the precise species.

For more information on wood identification in the context of personal property such as antiques, see the article:

Wiedenhoeft, A.C. 2006. The limits of scientific wood identification. - Professional Appraisers Information Exchange. Vol. 4(2): 16.

Images of the transverse surface of three hardwoods (left) and three softwoods (right)


Specimen size:

Specimens 1 X 3 X 6 inches are recommended for purposes of identification. If only small specimens can be supplied for examination, as is generally the case with antique furniture, we will try to provide an identification. We do not identify charcoal samples, nor samples from archaeological contexts except by prior arrangement.


Technique for removal of small samples from valuable wood products:

Small samples must be split from large items rather than shaved or gouged. To produce a good sample, use a sharp knife or small chisel and cut across the grain to a depth of about 3/16 inch. Make two such cuts at least 1/2 inch apart. If a knife is used, a splinter can be split out by prying up at one of the incised points. If a chisel is used, the edge can be placed in one of the cuts and then angled to travel down the grain to the other cut. A sharp tap will produce a good specimen. If the specimen cannot be rolled between thumb and forefinger without crumbling or breaking, do not submit it.


Preparation for shipment:

If more than one sample is submitted, individual items should be clearly labeled from 1 up to 5, with the numbers marked directly onto large samples. For small samples, use individual envelopes (e.g. coin envelopes) with the information for the enclosed sample marked on each envelope. Your results will be reported by number - do not use letters or other codes. Do not tape samples to cards or paper because they can be easily damaged when the tape is removed. Do not place any specimen larger than a toothpick in a normal paper envelope; such packaging is frequently damaged by the postal service mail processing machines. Use a padded envelope or small box instead. Samples submitted without letters will not be identified. If you require delivery confirmation, send your request via a carrier that can provide such information to you.


Determination of origin:

With our wood anatomical identifications we typically do not provide information regarding the origin of an item.


Age determination:

No attempt is made at this Laboratory to ascertain the age of wood specimens.


Forensic work:

The Center for Wood Anatomy Research does not identify wood specimens for private parties engaged in legal disputes, nor does it identify specimens for individuals or businesses who may be in violation of CITES or Lacey Act provisions, as this would conflict with its role in providing scientific expertise on these matters to other government agencies. Specimens are accepted from law enforcement agencies across the country.


Number of Samples:

The Center for Wood Anatomy Research will identify a maximum of five wood samples per household or business per calendar year as a free public service to U.S. citizens. We try to accommodate inquiries from non-citizens, but such requests are typically assigned a low priority. Persons or businesses in need of more than five identifications per year should seek a private consultant to provide this service.


Duration of Process:

Wood identifications can take anywhere from 5 minutes to many hours, depending on the type of wood, the size and quality of the sample, the information provided with the sample, and several other factors. In most cases, specimens are identified within 4 weeks. Samples are discarded after identification; small samples are often destroyed in the identification process.


Send your samples to:

Center for Wood Anatomy Research
USDA Forest Service, Forest Products Laboratory
One Gifford Pinchot Dr.
Madison, WI 53726-2398