Abstract:
The relationships of several wood quality traits with seed origin
and phenological characteristics, measured at a young age, were
tested from six seed sources in a young Douglas-fir (Pseudotsuga
menziesii (Mirb.) Franco) provenance plantation. The wood quality
traits measured were wood density, uniformity of wood density,
percentage latewood, fiber length, Runkel ratio, and holocellulose
content. Data for each seed source concerning the phenological characteristics
of bud bursting time, bud set time, and needle length
during the second growing season, were obtained from an earlier
study. Seed origin data concerning the latitude and elevation of each
seed source were also obtained from an earlier study. As an estimate
of mature wood properties the outer three annual rings (most samples
contained ten rings) away from the pith were used. It was hoped
that these relationships would show possible predictors of mature wood
properties from young seedlings. Such predictors could be used as
selection criteria for out planting seedlings with desired wood properties
or as early indicators of the genetic influence on wood properties
in genetic experiments.
The overall average wood density, uniformity of wood density,
percentage latewood, and annual ring width were measured for each
of the six seed sources. These measurements were used to test the
influence of seed origin or phenological characteristics (measured at
age two) on juvenile wood formation. These same traits were
measured ring by ring, from pith to bark, in each of the seed sources
in an attempt to explain some of the results encountered.
The latitude of seed source origin showed a significant relationship
with mature wood fiber length indicating strong genetic control.
Time of bud set appeared to have an influence on holocellulose content
in mature wood. Needle length showed a significant negative
correlation with average wood density but not mature wood density,
indicating it may have some influence on wood formation but may not
be used as a predictor of future wood properties. From the variation
patterns in wood density, uniformity of wood density, percentage
latewood, and ring width from pith to bark it appeared that a possible
relationship between wood formation and crown-development may
exist.
