Severe Warp Development in Young-Growth Ponderosa Pine Studs
Keywords:Compression wood, diagonal grain, heartwood, kiln-dried, knots, juvenile wood, spiral grain, warp
AbstractAnatomical and physical characteristics of severely warped, young-growth, ponderosa pine studs, dried by two different methods, were analyzed with respect to bow, crook, and twist. Statistical analysis revealed that: (1) drying method had no effect on the relationship between warp and the wood characteristics studied; and (2) a large portion of the variation in warp could not be explained by any of the measured factors. Of the characteristics analyzed, the presence of the pith appeared to have the greatest effect on warp severity. Contrary to expectation, little compression wood was found and was consequently of minor importance in the development of severe warp. Although studs with a layer of heartwood along one face were prone to severe crook, there was no apparent relationship between warp and the percentage of heartwood in a stud. Other factors such as density, knots, and grain angle could not be identified as major factors in the development of severe warp.
Arganbright, D. G., J. A. Venturino, and M. Gorvad. 1978. Warp reduction in young-growth ponderosa pine studs dried by different methods with top-load restraint. For. Prod. J. 28(8):47-52.nBalodis, V. 1972. Influence of grain angle on twist in seasoned boards. Wood Sci. 5(1):44-50.nDutorr, A. J. 1963. A study of the influence of compression wood on the warping of Pinus radiata D. Don. timber. South African For. J. No. 44:11-15.nGaby, L. J. 1972. Warping in southern pine studs. USFS Res. Paper SE For. Exp. Sta. No. SE-96.nHallock, H. 1969. Sawing to reduce warp of lodgepole pine studs. USDA For. Serv. Res. Pap. FPL 102, Madison, WI.nKloot, N. H., and M. W. Page. 1959. A study of distortion in radiata pine scathings. Div. For. Prod. Tech. Paper No. 7. CSIRO, Australia.nKoehler, A. 1955. Guide to determining slope of grain in lumber and veneer. Mimeo No. 1585. USDA For. Serv., FPL, Madison, WI.nMckay, J. F. G., and B. L. Rumball. 1971. Drying of distortion-prone juvenile core radiata pine for house studs. Aust. Timber J. 37(6):43-57.nNoskowiak, A. F. 1963. Spiral grain in trees. … A review. For. Prod. J. 13(7):266-275.nVan Der Merwe, J. J. 1973. Strength and warp in kiln dried South African pine timber as affected by drying process, spiral grain, and other factors. CSIR Spec. Rep. HOUT 56, South Africa.nVoorhies, G. 1971. The cause of warp in young-growth ponderosa pine lumber. Arizona Forestry Notes No. 6, School of Forestry, Northern Arizona University.n
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