Severe Warp Development in Young-Growth Ponderosa Pine Studs


  • John R. Shelly
  • Donald G. Arganbright
  • Michael Birnbach


Compression wood, diagonal grain, heartwood, kiln-dried, knots, juvenile wood, spiral grain, warp


Anatomical 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.


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