Measuring Timber Products Harvested from Your Woodland Paul Oester and Steve Bowers

Archival copy. For current version, see: https://catalog.extension.oregonstate.edu/ec1127 FOREST MEASUREMENT EC 1127 • Revised December 2009 Measuring Timber Products Harvested from Your Woodland Paul Oester and Steve Bowers Contents Fundamentals of measurement ..............1 anaging woodland property offers you the opportunity Measurement units ...............................2 Board foot ............................................. 2 to harvest a variety of products, depending on timber Cubic foot .............................................. 2 quality and quantity, harvest economics, and market Cord ..................................................... 2 M availability. Among these products are saw logs (for lumber Linear measurements .............................. 2 or plywood), peeler logs (for plywood), pulpwood, fuelwood, Weight .................................................. 3 poles, piling, and posts. Measuring logs ....................................3 Board-foot log rules ................................ 3 Knowledge of measurements used in the wood products Log scaling ............................................ 4 industry can help you make management and marketing deci- Board-foot volume .................................. 4 sions that ultimately will increase financial returns from your Selling logs by weight ............................. 4 woodlot. Cubic-foot volume ................................... 5 Defects .................................................. 7 This publication describes measurements used to buy and Log grading ........................................... 8 sell timber products. You can get more information from OSU Scaling tickets ........................................ 8 Extension agents, consulting foresters, timber product buyers, Exporting logs ................................... 13 state service foresters, USDA Forest Service foresters, and the Measuring other products ................... 13 staff of log scaling and grading bureaus. Poles and piling ................................... 13 Posts .................................................... 15 Pulp ..................................................... 15 Fuelwood ............................................. 16 Fundamentals of measurement Some final notes ................................ 16 The type of timber product determines its unit of measure- Appendices A. Log truck carrying capacities .............17 ment. You sell saw logs by board feet, cubic feet, or weight; B. Pole and piling dimensions.................17 pulpwood by weight; and poles by board feet or linear feet. C. Weight of wood at different Log scaling and grading bureaus provide independent moisture levels ................................. 18 measurement and standardized rules for the buyer and seller. D. Approximate cordwood volume for young Douglas-fir ............................. 18 Log measurement rules may vary among major regions of the United States. For more information .......................... 19 In the Pacific Northwest, saw logs are measured by the Scribner log rule, which estimates volume in board feet, based Paul Oester, Extension forester, Union on the small-end log diameter and the log length. For pole and County Extension, Oregon State University. piling sales, board-foot volume is estimated using top diam- Steve Bowers, Extension forester, Lane eter, length, and circumference or large-end diameter. County Extension, Oregon State University. Special tables (some of which are in this publication), tools, and experience are necessary to make accurate estimates of log quality and quantity. Table 1 outlines measurement units for some common wood products. See also Tools for Measur- ing Your Forest (Bowers 2008). Archival copy. For current version, see: https://catalog.extension.oregonstate.edu/ec1127 Measurement units Table 1. Common forest products The first step in measuring forest prod- and their measurement units. ucts is to define the units. Here are the ones Product Measurement units you’ll use most often. Saw logs Board foot Scribner and peeler logs Log grades, export grades Board foot Cubic feet Weight This is the most common unit of measurement for saw logs and peeler logs. Poles and piling Diameter, Visualize a board foot as a board 1 inch circumference, or thick by 1 foot wide by 1 foot long large-end diameter (figure 1): Length Bd ft = [thickness (in) x width (in) x Surface characteristics length (ft)] ÷ 12 in Fuelwood Cord For example, a plank 2 inches by 8 Weight inches by 24 feet contains 32 board feet: Pulpwood Weight (2 x 8 x 24) ÷ 12 = 32 Cord Board-foot volume usually is expressed in 1,000 board feet (MBF). Cord A cord is the amount of wood in a neat stack 4 feet wide by 4 feet high by 8 feet Figure 1. Board foot. long (128 cubic feet). It is the most common U.S. measurement of pulpwood and fuelwood. Cubic foot A cord rarely exceeds 90 cubic feet of A cubic foot is a solid piece of wood solid wood. (The bark and empty spaces 1 foot wide, 1 foot thick, and 1 foot long between the pieces of wood make up the (figure 2). Cubic feet give a more accurate rest of the space). The amount of actual log volume estimate than board feet. A high wood depends on the size and shape of degree of accuracy results from the consis- pieces, the presence and thickness of bark, tent measurement of the solid wood content and the method of stacking. of a log, regardless of its size. One variation is the rick or short cord— The cubic foot is used primarily to mea- a stack of wood 4 feet high and 8 feet long, sure pulpwood volume, but there is grow- which is made up of pieces that are less ing interest in using it for saw log measure- than 4 feet long. A face cord has pieces ment. averaging 16 inches long and measures Wood fiber volume measurements in- 42 cubic feet or one-third of a cord: clude the following: (4 ft x 8 ft x 16 in) ÷ 12 in = 42 • The cunit—100 cubic feet of solid wood (CCF) Linear • The cubic meter measurements 3 (m )—35.314 cubic Use feet and inches in feet, the standard selling specialty products log volume mea- such as poles, piling, fence sure for most of the posts, mine props, railroad world other than ties, car stakes, or hop poles. the United States Sell each product by the piece. In these cases, length and strength are more im- portant than actual volume. Figure 2. Cubic foot. 2 THE WOODLAND WORKBOOK Archival copy. For current version, see: https://catalog.extension.oregonstate.edu/ec1127 Weight Wood outside scaling cylinder Weight is becoming more Length of log prevalent as an estimate of volume, particularly when you sell logs that are small, expensive to measure, uniform in diameter, taper, and length, and that are low in value. Diameter of cylinder When you sell logs by weight, sample scale your log loads peri- Figure 3. The scaling cylinder. odically. Sample scaling involves weighing and scaling a load of logs to determine a board-foot-to- weight conversion. Length of log Sample scaling assures you a fair price because conversions are affected by species (wood density), log size, moisture content, and the amount of sapwood and heart- Small-end diameter wood. (Sapwood has more moisture and thus is heavier.) As weight Figure 4. Measuring small-end diameter and length is per board foot increases needed to determine board-foot volume. the value per MBF increases, as long as the price per pound is constant. to scale within cylinders of various sizes, allowing 0.25 inch for kerf. Scribner decimal C is a modification of the rule. It rounds values to the nearest 10 board feet and drops the final digit. For Measuring logs example, if Scribner volume is 503, Scrib- ner decimal C is 50. Scribner volume tables used in the industry are rounded. So, a log with 504 board feet would read 500. Board-foot log rules There is no taper allowance, so the rule In the majority of cases, you sell logs by normally underestimates volume for logs the board foot. The log rules used to con- more than 16 feet long. Wood outside the vert log size into board feet are a standard scaling cylinder (figure 3) increases as taper measure of volume determined by custom and length become greater. The amount and agreement. They estimate the lumber of wood product (lumber or veneer) that volume you can cut from a log. can be cut from the area outside the scal- Because logs taper and are not square, ing cylinder is called overrun. Overrun is board-foot log rules take into account the expressed as follows: width of the saw blade (kerf) and the slabs % overrun = cut from a log to square it and trim the ends. (bd ft lumber – bd ft net log scale) Since 1825, more than 50 different log x 100 rules have been devised and used in the bd ft net log scale United States and Canada. Only a few remain in use today. None predicts exact The amount of overrun that occurs lumber recovery except when nearly cylin- when a measurement is less than the actual drical logs are sawed according to a particu- lumber volume cut is a significant factor to lar rule. Buyers and sellers must be aware consider when you measure long logs with of log rules’ limitations in business transac- a high degree of taper. tions. Improved sawmill efficiency, narrow saw In 1846, J.M. Scribner devised the log kerf, and the use of slabs of wood cut from rule that is used most often in the Pacific outside the scaling cylinder also influence Northwest. He diagrammed 1-inch boards the chances for overrun. FOREST MEASUREMENT 3 Archival copy. For current version, see: https://catalog.extension.oregonstate.edu/ec1127 Log scaling of the divide. Always contact your buyer or mill before you cut because minimum The purpose of log scaling is to provide length and diameter requirements, species a uniform method of log volume measure- preferences, and trim allowances may vary. scaling and grading 22 inches When you know log length and diameter, bureau policy. A trim you can use log volume tables to deter- allowance is required mine gross board-foot volume (figure 6). A for all logs to compen- complete set of tables is available from log sate for damage to the scaling and grading bureaus. ends during logging You can estimate net volume once you and for squaring log deduct the volume lost to defects.

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