. Journal of forestry . .If 1 ... 1 \ : \ i ^ 1 I ! n f iii, \ \ \.. ? -It. f. IX.,^, ^^U. /-. Fig. 3.—Sise and occurrence of knots i>i Ihc first iS feet of an average red spruce Outer log line shows form of tree ^5 inches in diameter 4}^ feet from ground, inside lines show ohtlines of 20, 15, 10, and 5 inch trees. Zone i, clear of knots. Zone 2,dead-pin knots less than Yi inch. Zone 3. dead knots Yi to i inch. Zone 4. dead knots overI inch in diameter. Zone .s. live knots. tree bole, which though free from knots will have a crook in the ringgrain which cannot be eliminated in sa
. Journal of forestry . .If 1 ... 1 \ : \ i ^ 1 I ! n f iii, \ \ \.. ? -It. f. IX.,^, ^^U. /-. Fig. 3.—Sise and occurrence of knots i>i Ihc first iS feet of an average red spruce Outer log line shows form of tree ^5 inches in diameter 4}^ feet from ground, inside lines show ohtlines of 20, 15, 10, and 5 inch trees. Zone i, clear of knots. Zone 2,dead-pin knots less than Yi inch. Zone 3. dead knots Yi to i inch. Zone 4. dead knots overI inch in diameter. Zone .s. live knots. tree bole, which though free from knots will have a crook in the ringgrain which cannot be eliminated in sawing the log into hiinbcr. 784 JOURNAL OF FORESTRY The study of spiral was extended to cover the poorest grade of sprucehimber accepted in the airplane industry at the time the field-work was < Z Total OF Tn£SSin C^CHIMCk cutis M « S3 b , 41 y ft 1 ./ ?a % ^ 1 ?s •, / 0 ^ « 6 / ? 3/ 1 / 37 1. 30 101 S rrif c£/*r » 10 0 Tor fit ^ /tunB£7f ?j in cfiCMmen CLfisi . 3c / ./ 11- / r < /. ?t / 1 / ^ 1 i 1 on 93 f \ / IS / ?/ £317 } /. 2£ / :ii / IS Lcrr Fa
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Keywords: ., bookcentury1900, bookdecade1910, booksubjectforestsandforestry
