Stem Straightness and Compression Wood in a 22-Year-Old Stand of Container-Grown Scots Pine Trees

The distribution of compression wood in relation to eccentric growth and development of stem straightness was studied in a 22-year-old Scots pine (Pinus sylvestris L.) stand in central Sweden that was established with container-grown seedlings. Stem straightness was measured on the same 440 trees in 1986 and 1997. The number of stems with straight base sections increased from 60% in 1986 to 89% in 1997. Measurements of 72 sample trees in 2001 showed that 96% of the trees had developed straight stem bases. External geometry data of the logs was obtained with a Rema 3D log scanner. A sub-sample of 16 trees was randomly selected for analysis of compression wood distribution and eccentricity measurements. From each tree, 11 discs were cut at every 60 cm along the stem. All discs, except one, contained compression wood. Compression wood and pith eccentricity was most pronounced near the stem base but not significantly correlated to basal sweep. Severe compression wood content was correlated to pith eccentricity and bow height. In general, correlations were better for the basal sections of the logs. Even though most trees were straight, they contained large amounts of compression wood. It is evident that eccentric growth and compression wood formation play major roles in the development of stem straightness. In several stems, a spiral compression wood distribution pattern was found. Reasons for this are discussed.

[1]  Armas Jäppinen,et al.  Automatic sorting of sawlogs by grade , 2000 .

[2]  G. Rune.  Slits in Container Wall Improve Root Structure and Stem Straightness of Outplanted Scots Pine Seedlings , 2003 .

[3]  Marie Johansson,et al.  Moisture-induced Distortion in Norway Spruce Timber - Experiments and Models , 2002 .

[4]  S. Strand,et al.  Timber quality - natural regeneration or planting of Scots pine (Pinus sylvestris) , 1997 .

[5]  R G. Mason,et al.  CAUSES OF JUVENILE INSTABILITY OF PINUS RADIATA IN NEW ZEALAND , 1985 .

[6]  R. F. Sutton,et al.  Mounding site preparation: A review of European and North American experience , 1993, New Forests.

[7]  U. Johansson,et al.  Timber quality and volume growth in naturally regenerated and planted Scots pine stands in S. W. Sweden , 1998 .

[8]  O. Uusvaara.  The quality and value of sawn goods from plantation grown Scots pine. , 1985 .

[9]  M. Warensjö,et al.  Basal sweep and compression wood in young Scots pine trees , 2002 .

[10]  Christina Lundgren,et al.  Predicting Log Type and Knot Size Category Using External Log Shape Data from a 3D Log Scanner , 2000 .

[11]  M. Warensjö.  Compression wood in Scots pine and Norway spruce , 2003 .

[12]  F. Telewski.  Intra-Annual Spiral Compression Wood: A Record of Low-Frequency Gravitropic Circumnutational Movement in Trees , 1988 .

[13]  Micael Öhman,et al.  The measurement of compression wood and other wood features and the prediction of their impact on wood products , 2001 .

[14]  A. Lindström,et al.  Root deformation in plantations of container-grown Scots pine trees: effects on root growth, tree stability and stem straightness , 2004, Plant and Soil.

[15]  T. E. Timell.  Compression Wood in Gymnosperms , 1986 .

[16]  K. Cremer.  Recovery of Pinus radiata saplings from tilting and bending , 1998 .

[17]  A. Lindström,et al.  Root deformation in plantations of container-grown Scots pine trees : effects on root growth, tree stability and stem straightness , 1999 .

[18]  C. Andersson,et al.  Classification of compression wood using digital image analysis , 1995 .

[19]  Nicholls Jwp.  Wind action, leaning trees and compression wood in Pinus radiata D. Don. , 1982 .