Peterson Portable Sawmills

Glossary Q – S

A-C   D-G   H-K   L-P   Q   R   S   T-Z



Coincident with a radius from the axis of the tree or log to the circumference. A radial section is a lengthwise section in a plane that passes through the centerline of the tree trunk Rafter One of a series of structural members of a roof designed to support roof loads. Therafter sof a flat roof are sometimes called roof joists.

Raised track system
The ability to have tracks elevated off the ground. On the ATS, both tracks are vertically adjustable, where as on the WPF/ASM models, one track is fixed at a predetermined height (Hi/Lo).

The process of sawing lumber in two lengthwise, parallel to the wide face. It is usually, through not always, done through the middle of the board, producing two equal sized boards, each approximately half the thickness of the original. Resawing changes the thickness of the lumber but not its width.

The process of sawing lumber in two lengthwise perpendicular to the wide face and parallel to the grain. Ripping changes the width of the lumber but not its thickness.



Pale-coloured wood near the outside of the log which surrounds the denser, dead heartwood of a tree. Under most conditions the sapwood is more susceptible to decay than heartwood.

Saw kerf
(1) Grooves or notches made in cutting with a saw. (2) The portion of a log, timber or other piece of wood removed by the saw in parting the material into two pieces.

Saw logs
A log large enough to yield lumber. Usually the small end of a sawlog must be at least 6 to 8 inches in diameter for softwoods and 10 to 12 inches for hardwoods.

Sawlog top
The point on the central stem of sawtimber trees above which a saw log can not be produced. The minimum saw-log top is 7.0 inches d.o.b. for softwoods and 9.0 inches d.o.b. for hardwoods.

Trees suitable for production of saw logs.

Sawtimber removals
The net volume removed from the merchantable central stem (growing-stock portion) of sawtimber trees (Note: includes the saw-log and upper-stem portions of sawtimber trees.) When referencing removals from the sawtimber inventory as in tables 4-6 of the timber removals tables, only the volume in the saw-log portion of sawtimber trees (sawtimber volume) removed for roundwood products, logging residue, and other removals is included, and is expressed in thousands of board feet (International 1/4-inch rule).

To measure the weight or volume of a log or load of logs.

Determination of the gross and net volume of logs using the customary commercial volumetric units for the product involved.
OR Logs are measured (or scaled) for the purpose of estimating the amount of lumber that can be obtained. Once logs have been processed into lumber it is again necessary to quantify volumes produced.

Scrag mill
A special high-speed sawmill designed to saw small diameter logs. A skrag mill typically has two circle saws arranged in parallel which remove two slabs with one pass of the log producing a two-sided cant.

Wood that has been dried to a certain moisture content to improve its serviceability, either by air or kiln. According to the grading standards of the Western Wood Products Assoc., seasoned softwood lumber is defined as having a moisture content of 19 percent (oven-dry basis) or less.

Select grade
High-quality lumber. This grade is recommended for all finishing uses where fine appearance is essential. Widely used for high-quality interior trim and cabinet work with natural, stain, or enamel finishes.

The decrease in the dimension of wood resulting from a decrease of moisture content and generally occurring to the greatest extent between about 20 and 30% moisture content.

(1) On the ATS frame, the skids determine the distance between the uprights, allowing the carriage to run along the tracks smoothly. (2) Log skids (preferably wooden) elevate the log off the ground to minimise wastage at the base of the log.EZ Dogsor notches can be used on the log skids to assist in holding the log.

The exterior portion of a log removed in sawing timber.

Generally one of the botanical groups of trees that have no vessels and in most cases, needlelike or scale-like leaves. Examples include evergreen trees, conifers, cone-bearing trees or wood cut from these trees.

Group of similar individuals having a number of correlated characteristics and sharing a common gene pool. The species is the basic unit of taxonomy on which the binomial system has been established. The scientific name of a plant or animal gives the genus first and then the species as in Abies (genus) grandis (species). Species is both the singular and plural form of the word.

A discolouration in wood that may be caused by such diverse agencies as micro-organisms, metal or chemicals. The term also applies to materials used to impart colour to wood.

(1) The ability of a member to sustain stress without failure. (2) In a specific mode of test, the maximum stress sustained by a member loaded to failure.

Lumber that has gone through a planer so that its sides are smooth and uniform in size.