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.

Methods for the very early selection of Pinus radiata D. Don. for solid wood products

“…Leaning at an angle of 25 o from the vertical axis eliminate any uncertainty about the severity and area of compression wood formation as any leaning angle >25 o does not have any significant effect on the extent of compression wood formation and compression wood characteristics (Yamashita et al 2007). Lachenbruch et al (2010) did not observe any significant effect of lean angle above 10 o on the extent of compression wood formation in 2-3 year old radiata pine stems. In our study, trees were leaning at about 25 o in both leaning techniques (on platform and mechanical bending) during their leaning period when the maximum amount of compression wood with uniform properties was expected in the trees.…”

White spruce wood quality for lumber products: priority traits and their enhancement through tree improvement

“…Some authors have argued that the assessment of MFA in young stems could present valuable information for genetic selection and that tree improvement programs should focus their efforts on reducing values for this trait in corewood and, consequently, decreasing the variation in wood quality (Lima et al, 2004, Apiolaza, 2009. Young trees are especially prone to forming compression wood as a result of asymmetrical crown and other natural conditions such as light and slope (Timell, 1986, Lachenbruch et al, 2010a. The presence of compression wood is an undesirable trait for lumber products because, among other characteristics, it presents higher MFA values when compared to "normal" wood (Gorisek andTorelli, 1999, Andersson et al, 2000).…”

Characterization of mechanically perturbed young stems: can it be used for wood quality screening?

“…This can be caused by a canopy of irregular shape or it occurs in a tree that is subjected to a unidirectional wind loading, or due to eccentric loading from branches. Although the occurrence of compression wood in inclined stems and branches is well understood and documented, its occurrence in vertical stems is less so, with only a few reports considering young trees (e.g., Lachenbruch et al 2010). Since the main stem of the tree is of prime concern in production forestry, greater understanding of the occurrence and role of compression wood in vertical or near vertical stems is highly desirable.…”