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Show MARKS IN WOOD RECORD RE-CORD HEAVY WIND STORM Llttlo diagonal streaks or wrinkles ' across grain of n plcco ot timber not only betray weakness, but sometimes lndlcato periods of stress through which tbo wood passed when It was growing. Thoy may oven bo taken das a sort of fcheck on tlio official record re-cord of wind storms, as In tho case of somo lumbor tested at tho forest servlco laboratory at Madison, Wisconsin. Wis-consin. Tho marks aro caused by what are called "compression failures" which occur when tho libera bend or bucklo under a too heavy strain. In tutting up logs collected for experiments at tho laboratory, It was noticed that theso compression failures appeared on tho north sldo of a number of trees which came from tho same locality lo-cality In Florida. Hy counting the annual rings of tho wood and from knowledge of the tlnio when It was cut In tho forest, it was decided that the compression failures must havo been caused by a sevoro wind from the south about the year 1808. In miirles were made In Florida, and It was found that a hurricane had, in fact, swept over tho region at tho tlmo indicated. Tho experiments havo dotermlned that tho Btrength ot a piece ot wood may bo seriously impaired by slight compression failures duo to rough handling. Dropping a log across a skid may cause a compression failure fail-ure at tho point at which tho log strikes tho skid and It will bo at this point that tho log gives way when It breakB under a strain too bo-vero bo-vero for tho weakened fibers to withstand. with-stand. Hitherto unaccountable break ago in hickory wagon spokes and other presumably strong material aro now attributed to compression failures fail-ures caused by wind storms In tho B period of growth or by hard usago '.In lumbering and manufacturing processes. pro-cesses. Frost Check In Idaho Damago to llvo timber by frost checks Is also well known to woodsmen. woods-men. Tho cracking caused by sud den contraction of tho wood, Is most common during a rapidly lowering temperaturo to a degree below that to which tho trees aro necustomed. In February, 1904, H. B. Fenn. assistant as-sistant district forester at Ogdcn, and Goorgo O. Hentz, now supervisor of tho Caribou, at Montpo'.Ior, Idaho, wero rangers on tho Ultterroot forest, for-est, nnd had their headquarters at Elk City. Certain gorges of tho Salmon wero almost Inaccessible In summer on account of prcclpItlouB cliffs, and tho rlvor frozo sufficiently to bear a man only during tho coldest cold-est weather. During ono or theso cold snaps tho rangers wero out on a two weeks trip on skids nnd, having hav-ing completed tholr work decided to return by way of tho Dixie mining camp, necessitating a climb of four or llvo thousand foot over tho summit of tho divide between tho Salmon and Clearwater basins. Tho afternoon after-noon was warm, and v.ith tho heavy packs tho clinging of tho snow to flin nkliln Imnedod travel. Twlco it was notessary to build fires, and, warming tho skids rub them with beeswax nnd polish them with buckskin buck-skin gloves. Thus delayed the men arrived at tho camp nenr midnight, yet although It had becomo bitter cold no popping of tho trees was ob-served. ob-served. Noxt morning tho thormo meter wns 132 degrees below zero, and ns the men walked through tho forest for-est in tho still, frosty air, tho trees wero cracking like guns In ovcry direction. di-rection. In fnct, ignoring tho weather weath-er .thero lacked but tho small boy and toy balloon of a genuine Fourth of July celebration. Tho thicker bark protects, so that older and forg' or trees aro lmmuno from frost check. It is tho young growing trees that suiter. Tho report accompanying occurrence of nn otcaslonal frost check has somotimes start'ed an in-experienced in-experienced woodsman, whoso first impression was that someone was after af-ter liim with a rifle. |