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

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basis from mid-May to late Aug. Approx. 6 acres were used per day. This management reduced
brush competition with Douglas fir seedlings, did not significantly damage fir seedlings,
stimulated regrowth of grazed plants improving forage quality for big game and controlled
Senecio jacobaea. Av. daily weight gain of lactating ewes in 1981 was less than for the dry ewes
in 1982. Forage digestibility was adequate for dry ewes, but did not always meet the requirements
of the lactating ewes with lambs. These results are discussed in the general context of forest
management in the Pacific Northwest.
498. Riitters, K. and J.D. Brodie. 1984. Implementing optimal thinning strategies. Forest-Science
30(1): 82-85.
Keywords: thinning
economics
growth
yield
Abstract: [See FA 41, 3436; 44, 201] A method is described for comparing the results of
optimal thinning analyses based on different management or economic criteria (such as soil
expectation value, forest rent or m.a.i.). Optimal thinning regimes for Douglas fir and ponderosa
pine were calculated using dynamic programming algorithms based on 2 stand growth simulators.
Residual mean tree volumes were then plotted against stand density at varying time intervals. On
a graph of this kind, the time trajectory of optimal thinning regimes for even-aged stands is
approximately parallel to the line of maximum size/density.
499. Riitters, K.H. and D.A. Perry. 1987. Early genetic evaluation of open-pollinated Douglas-fir
families. Forest-Science 33(2): 577-582.
Keywords: genetic tree improvement
genetic relationships
growth
tree phenology
Abstract: A summary is given of experiments to determine the correlation of seed wt. and
growth and phenology of seedlings of 14 families in a cold frame with ht. of saplings from earlier
seed crops of the same families in 5 plantations at 9, 12 and 15 yr old. With some exceptions,
correlations of seedling variables with field ht. were poor. Highest correlations with 15-yr ht.
were for budset at 117 days, ht. and branching index of seedlings. Seedling growth and phenology
values were generally poorly correlated with seed wt. Seedling/sapling correlations, however,
were related to seedling/seed wt. correlations. Seedling/sapling correlations improved between 9
and 15 yr old.
500. Riley, C.M., C.J. Wiesner, D.W. Scott, J. Weatherby and R.G. Downer. 1992. Evaluating the
field efficacy of Bacillus thuringiensis Berliner against the western spruce budworm
(Lepidoptera: Tortricidae). In Pesticide-formulations-and-application-systems:-11th-volume Ed. -
.L.C. Bode, -DG. ASTM, Philadelphia, USA. pp. 271-290.
Keywords: tree/stand protection
stand conditions
tree/stand health