Stem form and compression wood formation in young Pinus radiata trees

Abstract

The crooked stems of some individuals of radiata pine ( Pinus radiata D. Don) can hinder volume recovery and wood quality. To infer causes of crookedness and to learn how lean angle affects compression wood (CW) formation we studied 5-year-old trees in southern Chile. Eight initially straight and eight initially crooked trees were tethered initially to angles of 15° or 30° or were left untethered for 131 days (48 trees total). There were no significant differences between straight and crooked trees in the extent of CW in pretreatment wood or in the relationship between stem angle and CW extent. Crooked trees, however, righted themselves more quickly than did straight trees at angles <15°, a result that supports the overcompensation hypothesis for the development of crooked stems. Stem angle had a complex effect on CW extent. In 2- to 3-year-old wood there was no meaningful effect of angle on CW extent. One-year-old wood produced less CW at stem angles <10° than at stem angles >10°, but above or below that threshold, there was no meaningful effect of angle on CW extent. The intertree differences in CW extent, as well as the correlation of leader CW extent with bole CW in the best individuals, suggests that CW assays could be used for early screening for wood quality.