Log Scaling

1. Log Scaling

2. WHAT IS SCALING? • Scaling is the process by which the net usable content in timber products is ascertained and expressed in an acceptable unit of measure. (BF, CF, L.F., Tons, Cords, etc.).

3. REASONS FOR LOG SCALING • As a measurement for payment purposes. • It serves to gauge work accomplished. • As a measurement of inventory. • It serves to measure the efficiency of the mill (recovery).

4. SCALING EQUIPMENT • A. Scale stick. • B. Loggers tape. • C. Tape measure. • D. Hatchet or Spud stick. • E. Caliper. • F. Hand-held data recorder.

5. Definition • Measurement • Gross volume • Merchantable (Merch) (Net) volume • Grade • We measure to determine value of the logs we sell to the mill • Saw logs are usually measured in MBF or 1000 board feet

6. Measurements • Diameter • Measured inside the bark on small end • Take two measurements 90 degrees from each other. • Length • Western Oregon minimum 16’ • 1’ multiples • Minimum of 8” trim • Rule of Thumb is 1’ trim • Logs 42’ plus scaled as two logs

7. QUALIFICATIONS OF A SCALER • The average scaler scales (approximately) what represents 25 MMBF a year. Assuming an average delivered log price of $450/MBF, this would be $11,250,000 worth of logs.

8. When looked at in this light, it shows a Scaler must be: • Honest and unbiased. • Be meticulous with the quality of his or hers work. • Realize the responsibility a Scaler has to the buyer and seller. • Have an aptitude for arithmetic. • Be of good moral character. • Maintain a professional appearance!

10. Check Scaling • Check scaling is the re-scaling of all or a part of the materials that have previously been scaled in order to determine the accuracy of the original scale. It is also used to identify if there is a variance and if so, resolve it through the log review

11. Qualifications of a Check Scaler • The ability to analyze and present the facts without bias. • A proficiency for training Scalers. • Good communication skills. • Sufficient knowledge and experience. • Be able to admit when he or she is wrong.

12. Scale Tickets • Scale tickets are used to provide information to the mill and timber owner. • The following information can be found on a scale ticket • Species • Grade • Gross scale • Net scale • Deductions • Log brand • Trucker • Destination • Log owner

13. Scale Tickets • The scale ticket breaks down each load by log and organizes the information into an easy to read format. • The ticket is important to the logger so he can make adjustments on production • It is important to the log owner to make sure they are being paid for all of the logs

15. Gross Volume Determination

16. Scribner Log Rule • Developed by JM Scribner in 1846 • He drew little pictures to estimate how many boards would fit in a given log • Assumes a ¼ inch kerf • No taper is included • Scribner rule also underestimates the mill output of lumber

17. Scribner Log Rule

18. Scribner Decimal C • Slight modification of the Scribner log rule • Scribner volumes are rounded off to the nearest 10 board feet and the last zero is dropped, so tens of board feet are reported • Scribner Dec C log rule is used Primarily in the Western US • When reading the volume from the scale remember to add a zero

19. Discussion of Log Rules • There are more than 100 log rules in North America • Often huge differences between log rule estimate and sawed lumber tally because: • Logs are treated as cylinders • Diameter is measured at the small end • Volume from log taper is ignored • It is assumed that all sawmills are equal • Efficiency is not equal • Kerf is not equal • Sawmills extract different sized boards

20. Discussion of Log Rules • Despite all of the variances in log rules, they are the primary determination of log value

21. Scaling Cylinder • Diagram rule uses 1" boards 1/4" sawkerf, no wane, actual size not nominal. • Minimum product size is 1"x 4" x 6’. • Volume rounded to nearest 10 BF and last cipher dropped (decimal C).

23. Board FootVolume of Lumber

24. Cord Wood • Cords • 1 cord = 4’ x 4’ x 8’ (128 cubic feet) • The cord volume of any pile of stacked wood is: • # cords = length (ft) x Height (ft) x Width (ft) divided by 128 • Rule of thumb • Solid wood volume of a cord is about 500 board feet • Weight equals about 4000lbs for softwood and 5000lbs for hardwood

25. Volume by ton • Weight is an alternative method for measuring harvested wood • This is standard practice for pulpwood • Is becoming more popular for saw logs • Primarily used for a “chip n saw” • “chip n saw” is a log that is bucked down to a small top diameter • Usually 2” • The saw logs are bucked out and the rest is used for pulp

26. Merchantability Specs • All the below specifications can be changed by the contract. • Usually 33 1/3% sound (Net Scribner used for Cubic Merchantability). • Minimum Diameter generally 6", minimum scaling length 14’. • Each segment considered on its own merits.

27. PRODUCT RECOVERY WHAT ARE THE VARIABLES? • Accuracy of the scaler. • Saw kerf, Target Size. • Products manufactured. • Sawmill efficiency. • Log size. • Log Taper. • Amount and type of defect in logs.

28. Product Recovery • Board foot = 80-250% recovery for lumber. • CF = 40-70% recovery or 6.5-10 BFlum/CF log (LRF). • BF plywood recovery = 2.5-3.5 MSF/MBF • CF plywood recovery = 1.5-2.0 MSF/CCF.

29. LENGTH MEASUREMENTS

30. Second cut logs, measure short side to short side

31. Butt cut logs, measure short side to where scaling cylinder emerges butt

32. LENGTH MEASUREMENTS • Broken logs, measure from point where protrusions would fill void and take appropriate defect deduction if necessary. • Forked logs, measure each fork as a separate log (if merchantable). • Scaling length is actual length minus trim (normally 1’) • Maximum log length is 40' plus trim. • Minimum log length is typically 16’ plus trim. • Most logs are recorded in multiples of 2' excepting some special product logs.

35. Measurements • Any log longer than 40’ will be scaled as two logs. • The logs will be split in half • Diameter of the first log will be that of the small end of the log • To determine the diameter of the second log: • Determine the difference between the small end diameter and the large end diameter • Divided the difference in half and add to the small end diameter • If the difference is an odd number, round up to the next even number

36. Measurements • For example • A 42’ log that has a small end diameter of 18” and a large end diameter of 27” • The first log would be 22’ with a diameter of 18” • The second log would be 20’ • The second log diameter would be determined by subtracting 18” from 27” leaving us 9” • We would round 9” up to 10” and then divide in half leaving us 5” • We would then add the 5” to the small end diameter of 18” leaving us a 23” diameter for the second log

37. Diameter Measurement

38. Measure diameters inside of bark and cambium layer.

39. Measure through the true center of the log (ignore pith).

40. Take two measurements, narrow way first and at a right angle to first measurement.

41. Disregard bumps and depressions

42. Read stick or tape straight on, not obliquely

43. Forked, knot whirled or swelled ends should be measured behind swell.

44. If one measurement falls exactly on the 1/2" round up, if both do, round one up and the other down.

45. Determine the average of both measurements (if average is on the 1/2", round down).

46. NET VOLUME DETERMINATION • WHAT IS DEFECT? • A defect is anything that causes a loss in volume of lumber within the scaling cylinder (except for some diameter reduction defects). For cubic, there is no scaling cylinder, so all volume loss is defect. • Stain is not considered a defect unless associated with rot. • In order for a log to be merchantable, a minimum of 1/3 of the log must be sound wood.

47. Bark seams Breaks and splits Burls Cat Faces Heart checks Weather checks Frost cracks Crook Crotch Fire Scars Large knots Knot clusters Rotten knots Metal Lightning scars Massed pitch Pitch seams Pitch spangles Pitch rings Stump pull Shake Conk rot Heart rot Stump rot Sap rot Twist Worms & bugs Types of defect:

48. Length Deductions • Breakage usually takes 2’ on each side of the break. If the break is close to the end and an 8’ log isn’t able to be recovered from the end, then the whole end of the log has to be deducted. Breakage is an oversight of the logger and should never have to be scaled. • Crook: take enough length to clear up the crook. • Stump rot: if 1/3 the scaling cylinder is affected, then take a 2’ deduction. If 2/3 the cylinder is affected, take a 4’ deduction. If the entire cylinder is affected, then take an 8’ deduction. • Shake: Determine % of log affected and take that % times length of log and that would be your length deduction. For slight shake, 2’ deduct is usually enough. For severe shake, a 12’ cut is needed. • Dry rot: determine % of log affected and take that in length. • Pitch spangle: Determine % of log affected and take that in length. • Conk: Determine % affected and take that in length. • Sweep: Try to get 2 logs out of the log and deduct a couple of feet for the sweep. If the sweep is at the very end of the log, then the whole end will have to be deducted. The rule states that whatever % is outside the scaling cylinder that is what is deducted. Some mills allow for some type of sweep and there are no deductions made. Usually a rule of thumb is to measure the log and if the sweep is less than the diameter then there are no deductions.

49. Scribner Length Cut Example

50. DIAMETER CUT • 1. Scaling cylinder not considered. • 2. May be a portion of a diameter cut (1/3rd of a 2" diameter cut for 10').