12-20-1995 Council Agenda - Laserfiche WebLink

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DNR Forestry Fax:612- 772 -7599 Dec 15 '95 9 :27 P.03/03 MAKING LOGS FROM URBAN TREES MAY 7, 1992 GENERAL SPECIFICATIONS FOR LOGS DIAMETER: A LOG MUST BE MEASUR.ED•ON THE SMALL END INSIDE BARK TO DETERMINE THE SCALING DIAMETER AND VOLUME. A sawlog must be at least 8 inches diameter small end inside bark. Some sawmills may vary the size log they will take based on species and amount of cull. LENGTH: FOR THE MOST PART A LOG NEEDS TO BE AT LEAST 8 FT. 4 INCHES LONG. The four inches is for trim allowance. Some sawmills are able to saw 6 FT. lengths. If R. R. ties are a product the log needs to be cut 8 FT. 9 IN. Longer logs are sometimes desirable but urban trees usually have short trunks. DEFECT: SWEEP AND OTHER CURVES IN THE LOG SWEEP AND CROOK ARE TWO OF THE MAIN FACTORS THAT DECREASE TOTAL LOG VOLUME. AS THE LOG DIAMETER DECREASES, SWEEP OR CROOK BECOMES A BIGGER FACTOR. A sweepy large diameter log will have so% sawable volume. A small diameter log with the same amount of sweep may be an unusable log. Defect is also caused by ring shake, rot, hollow centers and other factors. Logs with defect that have about 50% solid volume are still worthwhile to saw. Shake if it can be seen on the log ends should be deducted heavily from the solid content of the log. Knots are not volume defects but cause a log to be lower in quality. LOG QUALITY: Log quality is based on size, defect and the amount of knots that can be seen on the bark. Almost all of the urban tree logs are sawlog quality. Very few of them are veneer quality. VENEER, is the highest quality log but only the largest diameters, straightest with few or no bark distortions will meet veneer specs. If a large volume of veneer is. suspected, call someone to get further information. METAL: METAL AND OTHER FOREIGN MATERIA1 IS SOMETIMES FOUND IN LOGS. Most sawmill operators have had experience with it. It is their major fear in terms of downtime and equipment breakage. However, some operators have made a business of sawing logs from urban areas. Some sawmill operators use hand held metal detectors. The log supplier and the log user need to decide ahead of time how to handle this situation when it occurs. LIMBS MUST BE CUT FLUSH TO THE LOG SURFACE. SWELLED TREE BUTTS, CROTCHES OR OTHER WOOD THAT IS PROTRUDING AWAY FROM THE NORMAL LOG TAPER MUST BE CUT OFF. VOLUME DETERMINATION: Average small end diameter and log length will give the log volume on the sawlog volume table shown on the back. Page 48