Publication: American Forestry
Washington, DC, United States
BY DONALD BRUCE
Thirty-six years ago a telegraph bracket and insulator was nailed to a Douglas fir tree near Arcata, Cal. A few years later a falling branch badly damaged it and the wire which it had been supporting was removed. The tree was growing thriftily, adding every Summer to its diameter a new layer of woody material and this growth gradually pushed out around the bracket on all sides, leaving it buried in the tree trunk. At the end of 26 years (or 10 years ago) the tip of the glass insulator finally disappeared from sight and the only trace of it that could still be seen was a scarcely noticeable lump which looked like nothing more than a healed-over branch stub. A few weeks ago the tree was felled and the wood manufactured into barrel staves. The screech of the saw which happened to graze the edge of the glass called attention to this unusual "fossil".
Glass insulator — wooden bracket and iron nails uncoverd in sawing a Douglas fir stave bolt.
On splitting open the stave bolt the story became clear in all its details, as is shown by the accompanying illustration. The clearly defined annual rings of the rapidly growing tree form an unimpeachable historical record. The wood of the insulator bracket is still in good condition, and the oak of which it was made received an unintentional preservative treatment, having been thoroughly impregnated with the resin of the surrounding fir. The interesting specimen can now be seen in the wood collection of the Forestry Division of the University of California.