IntensIve sIlvIculture - Forest Science Labs - Research Network ...

Abstract: Relationships between tree traits and tree value for lumber production were
investigated. For the purposes of estimating relative economic weights for use in multitrait
selection in coastal Douglas fir (Pseudotsuga menziesii var. menziesii), tree height, diameter at
breast height, and branch diameter were measured on 164 trees (ages 36-66 yr) sampled from 11
intensively managed stands with a wide range of site attributes, growing conditions, ages and
stocking histories in western Washington and Oregon. Increment cores from a subsample (92) of
these trees were assayed by X-ray densitometry to determine wood density. Bole volume was
derived by summing the log volumes of all logs from each tree. Value of lumber recovered from
each tree was determined in a separate mill study using both visual and machine stress rated
(MSR) grading rules. Multiple linear regression was used to relate tree value to the growth and
wood quality traits. Stem volume and branch diameter significantly influenced tree value under
visual grading, with relative economic weights of 0.06 dmsuperscript 3 and -5.22 cm,
respectively. Wood density significantly influenced tree value under MSR grading (relative
economic weights: 0.06 dmsuperscript 3, -6.69 cm, and 0.06 kg/msuperscript 3, respectively),
where lumber strength is measured more accurately. These regression coefficients can be used
directly as economic weights in selection indices in the development of advanced breeding
programmes for Douglas fir.
29. Axelrood, P.E., W.K. Chapman, K.A. Seifert, D.B. Trotter and G. Shrimpton. 1998.
Cylindrocarpon and Fusarium root colonization of Douglas-fir seedlings from British Columbia
reforestation sites. Canadian Journal of Forest Research 28:1198-1206.
Keywords: planting operations
tree/stand protection
tree/stand health
Abstract: Poor performance of Douglas fir (Pseudotsuga menziesii) plantations established
in 1987 has occurred in southwestern British Columbia. Affected sites were planted with 1-yr-old
container stock that exhibited some root dieback in the nursery. A study was initiated in 1991 to
assess Cylindrocarpon and Fusarium root infection in planted and naturally regenerating (natural)
Douglas fir seedlings from 7 affected plantations. Percentages of seedlings harbouring
Cylindrocarpon spp. and percentage root colonization were significantly greater for planted
seedlings than natural seedlings. A significant linear trend in Cylindrocarpon root colonization
was observed for planted seedlings with colonization levels being highest for roots closest to the
remnants of the root plug and decreasing at distances greater than 10 cm from that region. This
trend in Cylindrocarpon colonization was not observed for natural seedlings. Cylindrocarpon
destructans var. destructans [Nectria radicola var., radicola] and C. cylindroides var. cylindroides
were the only species isolated from planted and natural conifer seedlings. For most sites,
percentage of seedlings harbouring Fusarium spp. and percentage Fusarium root colonization
were less than for Cylindrocarpon. Recovery of Fusarium spp. from seedlings and root
colonization levels were not significantly different for planted and natural seedlings from all sites.
30. Axelrood, P.E., M. Neumann, D. Trotter, R. Radley, G. Shrimpton and J. Dennis. 1995.
Seedborne Fusarium on Douglas-fir: pathogenicity and seed stratification method to decrease
Fusarium contamination. New-Forests 9(1): 35-51.
Keywords: nursery operations
tree/stand protection
tree/stand health
growth
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