Seven wood traits: shrinkage (longitudinal, tangential,
and radial), relative density, grain angle, tracheid length,
and fibril angle, and two growth traits, height and diameter
at breast height were analyzed in 413 trees belonging to 48
full-sibfamilies (4 pollen and 12 seed parents) from an 18-
year-old coastal Douglas-fir (Pseudotsuga menziesii var.
menziesii (Mirb.) Franco) progeny test . Clones from six of
the parents also were sampled. Six samples per age level
(age levels 0 to 4 along stem radii), with two rings in each
age level, were examined in a bolt taken at breast height of
the tree for shrinkage and relative density. Smaller sample
sizes were used for the other traits. Trends with age from
the pith were decreasing longitudinal shrinkage and fibril
angle and increasing radial and tangential shrinkage, grain
angle, and tracheid length. Relative density first
decreased and then increased beyond age level 2. Genetic
effects were minimal for wood quality traits except for
relative density. Most of the variation for wood quality
traits was within tree and between individual trees within
families. Genetic correlations between wood quality traits
were minimal except between relative density and radial
shrinkage, which was positive. Genetic correlations between
growth characters like height and diameter at breast height
and wood quality traits were also minimal except for
relative density and longitudinal shrinkage at early age
levels. Selection for increased height can be expected to reduce longitudinal shrinkage and relative density at early
age levels, and have virtually no effect on the other traits
studied. The results support current efforts to increase
wood production through genetic improvement in growth rate
by showing that current programs of selection for rapid
early height growth will not (with the exception of relative
density) result in substantial reductions in several wood
quality traits beyond the first few years of tree growth.
The demonstrated lack of substantial genetic effects for
several traits indicated that genetic improvement can
progress more rapidly by concentrating on a much smaller
number of traits. / Forestry, Faculty of / Graduate
| Identifer | oai:union.ndltd.org:UBC/oai:circle.library.ubc.ca:2429/41465 |
| Date | January 1993 |
| Creators | Koshy, Mathew P. |
| Publisher | University of British Columbia |
| Source Sets | University of British Columbia |
| Language | English |
| Detected Language | English |
| Type | Text, Thesis/Dissertation |
| Rights | For non-commercial purposes only, such as research, private study and education. Additional conditions apply, see Terms of Use https://open.library.ubc.ca/terms_of_use. |
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