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

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soil properties
Abstract: Twelve plots were established in 1972 in an 11-yr-old Douglas fir (Pseudotsuga
menziesii) plantation infected with Phellinus weirii, the cause of laminated root rot. All plots
were thinned and either interplanted with red alder (Alnus rubra) or fertilized at 5- to 10-yr
intervals with urea to determine the effect of nitrogen on tree growth and mortality caused by P.
weirii, or left untreated. Interplanted alder, however, failed to survive. Mortality was assessed at
intervals of 2 to 3 yr. Plots were inventoried (100% cruise) in 1978 and 1990. Growth over 12 yr
appeared better on fertilized than nonfertilized plots, but the difference was not significant.
Mortality caused by the preferential feeding of black bears [Ursus americanus] on the inner bark
of fertilized trees reduced the overall gain. Mortality caused by laminated root rot did not differ
significantly among treatments. Three months after the initial application of urea at 448 kg N/ha,
soil sampled to a depth of 30 cm was higher in ammonium and nitrate forms of nitrogen on
fertilized than nonfertilized plots, but increases were not significant. Numbers of soil bacteria
were directly correlated with soil ammonium content (P = 0.1092). Numbers of aerobic
actinomycetes were inversely correlated with soil nitrate content (P = 0.0398).
429. Newton, M. and E.C. Cole. 1989. Where does sulfometuron fit in Pacific northwest silviculture?
Proceedings-of-the-Western-Society-of-Weed-Science (Vol. 42): 121-128.
Keywords: release treatments
chemical release
stand conditions
tree/stand health
Abstract: Field trials in the Oregon Coast Range were conducted to evaluate sulfometuron
for weed control in established and newly-planted stands of Pseudotsuga menziesii. North Coast
sites were aerially-sprayed with 0.11 or 0.22 kg/ha sulfometuron +or- 2.2 kg/ha 2,4-D. South
Coast sites received 0.11 or 0.165 kg/ha sulfometuron, and this was compared with 1.65 kg/ha
hexazinone, 4.4 + 0.42 or 0.40 kg/ha atrazine + glyphosate +or- 1.25% surfactant (R-11). Weed
cover and tree damage were assessed visually. In South Coast sites, all treatments reduced weed
cover >50%. Broadleaved weeds and grasses were well controlled, but none of the treatments
suppressed shrub growth. Broadleaved weeds were best controlled by hexazinone, and all other
weeds by sulfometuron. On North Coast sites, all treatments reduced weed cover. Broadleaved
weeds, grasses, shrubs and Rubus ursinus were all suppressed, but ferns were not. 2,4-D
enhanced the effect of sulfometuron on broadleaved weeds and R. ursinus, but injury to P.
menziesii was also greater. This was acceptable on terminal growth