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

genetic relationships
139
Abstract: Silvicultural practices can influence black bear (Ursus americanus) foraging
preferences for Douglas fir (Pseudotsuga menziesii) cambial-zone vascular tissues, but little is
known about the role of genetics. To study the impact of genetic selection, vascular tissue
samples were collected from Douglas fir trees in 6 half-sib families from 5 different sites in north
central Oregon. Four replications of 3-tree non-contiguous plots were sampled at each site to
examine inter-and intra-site variation. Tree growth was measured as tree diameter at breast
height, and the absolute concentrations of 26 different terpenoids were determined by gas
chromatography/flame ionization detection from ethyl acetate extracts. The simple carbohydrates
fructose, glucose, and sucrose, and the phenolic glycoside coniferin were quantified using anionexchange
chromatography with pulsed amperometric detection. Cluster analysis was used to
reduce the number of variables used in analyses of variance. Results for the families studied here
indicate that tree growth and some terpenoids were under some level of genetic control.
Furthermore, allocation of constitutive terpenoids in vascular tissues was not at the expense of
tree growth. The sugars present in vascular tissue were affected by environment (site) and
genetics (family) and their interaction.
315. Kimball, B.A., D.L. Nolte, D.L. Griffin, S.M. Dutton and S. Ferguson. 1998a. Impacts of live
canopy pruning on the chemical constituents of Douglas-fir vascular tissues: implications for
black bear tree selection. Forest-Ecology-and-Management 109(1/3): 51-56.
Keywords: pruning
tree/stand protection
growth
tree physiology
tree/stand health
Abstract: The impact of live canopy pruning (removal of all live and dead whorls between
the ground and 5 m height, resulting in removal of ~40% of the live canopy) on the carbohydrate
and terpene content of vascular tissue was investigated in the lower bole of Douglas fir
(Pseudotsuga menziesii) on 4 sites in NW Oregon. Cambial zone vascular tissue samples were
collected from pruned and unpruned trees in the lower bole and within the live canopy. Current
year's radial growth was estimated from the mass of vascular tissue removed from the 800
cmsuperscript 2 area sampled from each tree. Chemical analyses were conducted to determine the
concentration of carbohydrates and terpenes in the samples. Results indicated that 2 yr following
treatment, pruning resulted in reduced growth and decreased carbohydrate content of the vascular
tissue. Pruning had no effect on the terpene concentration of the vascular tissue. The impact of
pruning on the foraging selection of black bears (Ursus americanus) was evaluated by surveying
bear damaged trees in a 50 acre stand of pruned and unpruned timber. Odds ratios indicate that
black bears were 4 times more likely to forage unpruned than pruned Douglas fir. Tree selection
may be explained in part by the higher availability of carbohydrates in the unpruned tree with
respect to the pruned tree.
316. Kimball, B.A., E.C. Turnblom, D.L. Nolte, D.L. Griffin and R.M. Engeman. 1998b. Effects of
thinning and nitrogen fertilization on sugars and terpenes in Douglas-fir vascular tissues:
implications for black bear foraging. Forest-Science 44(4): 599-602.
Keywords: fertilization
thinning
tree/stand protection