261 research outputs found
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Cone and seed insects and their impact on whitebark pine
Whitebark pine, Pinus albicaulis Engelm. is an important but declining high-elevation tree species in western forests. Regeneration of this species has been difficult and the impact of cone and seed insects unknown. Seven sites selected from the geographical range of whitebark pine in Idaho, Montana, Washington, Oregon, and California were examined for cone and seed insects and their impact. Ten different insect species were found affecting various reproductive structures of whitebark pine. Insects having the greatest impact across most sites were fir coneworm (Dioryctria abietivorella (Grote)) and western conifer seed bug (Leptoglossus occidentalis Heidemann). Coneworms infested up to 68% of cones collected, destroying up to 13% of the seed extracted. Seed bugs damaged up to 27% of the seeds. Pheromone traps for the ponderosa pine cone beetle (Conophthorus ponderosae Hopkins) and coneworms were tested. Ponderosa pine cone beetles were trapped at three of seven sites. Coneworms were trapped at two sites where pheromone traps were deployed. Further studies incorporating different cone crop levels of whitebark pine and other associated tree species are needed to fully determine the effect of cone and seed insects on whitebark pine seed and reproduction
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Analysis of Douglas-fir beetle population dynamics from aerial survey data using group size analysis
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Douglas-fir beetle population assessment : Idaho Panhandle National Forests
The unusually large amount of ice, snow,
and wind-damaged trees that occurred
during the winter of 1996-97 provided prime
habitat for populations of the Douglas-fir
beetle (DFB) (Dendroctonus pseudotsugae)
to build to epidemic numbers. Beetles
emerged during the spring and summer of
1998, attacking hundreds of thousands of
standing Douglas-fir trees. Beetle attacks
continued in green trees in 1999. This
report documents DFB population
assessments in 1999, including ground
surveys of current beetle populations and
aerial survey, which reports 1998 killed
trees
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An assessment of chloride-associated, and other roadside tree damage, on the Selway Road, Nez Perce National Forest
Tree damage following dust abatement/road
stabilization treatment was evaluated on 12.5
miles of the Selway River Road, Nez Perce
National Forest. Calcium chloride was applied in
June of 2000, mostly at a rate of 51b/yd2 (18,600
lb./acre) or 6.9 lb/yd 2 (25,700 lb/acre). 1,189
trees up to 30 feet from the road were examined
in June 2001 and again in December 2001.
Western redcedar and Douglas-fir were most
damaged by the chloride. Ponderosa pine was
the most tolerant of the tree species. Severity of
damage was associated with tree species,
proximity of trees to road, and CaCl2 application
rates. Cedar foliage samples collected in
November 2001 from symptomatic trees near
treated road averaged nearly seven times more
chloride ion concentration than the controls.
Treated Douglas-fir averaged 50 times more and
ponderosa pine average 30 times more than
their respective controls. As of December 2001,
12% of cedars were dead and another 18%
appear to be dying. Douglas-fir fared worse with
29% dead and 12% dying. Grand fir and
ponderosa pine had only 6% and 4%,
respectively, dead or dying
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Investigations of tree health at the Potlatch Corporation Cherrylane Seed Orchard, Idaho
Investigations were conducted from 1998-
2000 at the Potlatch Corporation's
Cherrylane Seed Orchard near Lewiston,
Idaho to evaluate presence and extent of
potentially pathogenic fungi on roots of
diseased stock and within the soil in current
and proposed plantation sites. The most
common group of pathogens encountered
was Fusarium spp.; F. oxysporum was by far the most common colonizer of tree roots and
soil. Phytophthora spp. (P. cacta rum and P.
pseudotsugae) and Pythium spp. (P.
irregulare and P. ultimum) were also common
root and soil colonizers. Cylindrocarpon spp.
(C. destructans and C. tenue) were isolated
at lower frequencies. Soil solarization with a
thin plastic tarp during the summer effectively
reduced populations of potential soil-borne
pathogens. Managers should continue to
monitor pathogen populations on stock and
within soil of proposed plantation sites in
order to reduce future disease impacts
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Effects of topical application of the biological control agent Biotrek on production of bareroot Douglas-fir and western white pine seedlings, USDA Forest Service Nursery, Coeur d'Alene, Idaho
A preliminary evaluation of the biological control formulation of Trichoderma harzianum marketed as BioTrek® was conducted on bareroot Douglasfir and western white pine seedlings at the USDA Forest Service Nursery, Coeur d'Alene, Idaho. The biocontrol material was applied topically on seed shortly after sowing and comparisons made between treated and untreated 1-0 and 2-0 seedlings. First-year Douglas-fir height and second-year white pine height and diameter were not affected by the treatment. BioTrek® significantly reduced white pine seedling root infection by Cylindrocarpon spp., but not by either Fusarium or Trichoderma spp. The major Fusarium species isolated from roots of nondiseased seedlings was F. oxysporum. Further tests of BioTrek® are underway at the nursery
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Effects of preplant soil treatments on Fusarium and Trichoderma populations and fungal root colonization of 2-0 nondiseased western white pine seedlings - USDA Forest Service Nursery, Coeur d'Alene, Idaho
Preplant soil treatments were implemented to determine effects on populations of potentiallypathogenic Fusarium and potentially disease-suppressive Trichoderma spp. as well as root colonization by these and other selected fungi on healthy-appearing, bare root 2-0 western white pine seedlings at the USDA Forest Service Nursery, Coeur d'Alene, Idaho. Soil treatments included fumigation with dazomet, bare fallowing with periodic cultivation, steam treatment, fallowing with amendments of Trichoderma harzianum biocontrol agents (BioTrek® and University of Idaho isolates [UI]), and incorporation of two cultivars of winter Brassica cover crops followed by biocontrol amendments (UI). Soil Fusarium populations were significantly reduced by dazomet fumigation; fallowing with biocontrol amendments and incorporating winter mustard crops with biocontrol amendments resulted in significantly higher Fusarium populations. Trichoderma populations were significantly decreased by dazomet fumigation, bare fallowing and steam treatment. Incorporation of Brassica crops did not significantly affect soli Trichoderma populations. Level of Fusarium root colonization was significantly reduced by dazomet fumigation and steam treatment. High levels of root colonization by rhizosphere-inhabiting isolates of Cylindrocarpon were common in some treatments. Assaying root colonization by selected fungi may supplement other parameters to evaluate effectiveness of soil treatments implemented to reduce pathogen populations and improve conifer seedling production
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