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dosage reduced or eradicated P. [Inonotus] weirii from infested stumps and roots. There were
small, if any, increases in effectiveness as a result of increased dosage, sealing with asphalt or
covering with plastic. Chloropicrin and Vorlex were more effective than methyl isothiocyanate.
Absence of significant effects may have resulted from large variations within treatments.
Assessments of inoculum survival in untreated stumps were similar with aseptic isolation
techniques and observations of fungal regrowth on cut surfaces of incubated root discs. Isolations
from fumigated stumps indicated greater survival of I. weirii in roots than shown by fungal
regrowth. Viable I. weirii was not found in most root discs where fumigant was detected by
bioassay.
609. Thies, W.G. and E.E. Nelson. 1987b. Survival of Douglas-fir injected with the fumigants
chloropicrin, methylisothiocyanate or Vorlex. Northwest-Science 61(1): 60-64.
Keywords: tree/stand protection
tree/stand health
Abstract: The fumigants were introduced into holes drilled past the centre of trees
uninfected, probably infected or definitely infected with Phellinus [Inonotus] weirii in a 47-yr-old
stand near Apiary, Oregon. Test dosages of chloropicrin or methyl isothiocyanate (MIT) were
applied in Mar. 1982 and of chloropicrin or Vorlex (containing MIT) in Apr. 1983. Of 120 trees
treated with fumigant, 95 trees were still alive in mid-Sep. 1984. After 3 growing seasons, all 45
trees treated with MIT and 21 of 45 trees treated with chloropicrin were still alive. After 2
seasons, crown condition was poorer in trees treated with Vorlex than in untreated trees or those
treated with MIT. Attempts were made to isolate I. weirii from trees that died during the study.
The fungus was isolated from all discs of an untreated tree, but from only 22% of root discs from
25 trees treated with chloropicrin or Vorlex. Roots have not been examined in trees still alive.
610. Thies, W.G. and E.E. Nelson. 1988. Bulldozing stumps and nitrogen fertilization affect growth of
Douglas-fir seedlings. Canadian-Journal-of-Forest-Research 18(6): 801-804.
Keywords: site preparation
mechanical preparation
fertilization
growth
Abstract: Eight treatments involving stump removal (either all stumps removed or the plot
left undisturbed) and broadcast application of ammonium nitrate (N at 0, 336, 672 or 1345 kg/ha)
were applied to 0.04-ha circular plots in a clear felling on the Olympic Peninsula, Washington.
Pseudotsuga menziesii seedlings were planted several months after treatment; d.b.h. and height
were recorded 5 and 8 yr after planting. Results showed that either bulldozing stumps or
application of nitrogen increased seedling growth. After 8 yr, bulldozing had increased seedling
height and d.b.h. by 23 and 43%, respectively; increases caused by nitrogen fertilizer were 13 and
17%, respectively.
611. Thies, W.G. and E.E. Nelson. 1996. Reducing Phellinus weirii inoculum by applying fumigants
to living Douglas-fir. Canadian-Journal-of-Forest-Research 26(7): 1158-1165.
Keywords: tree/stand protection
tree/stand health