Visible versus actual incidence of Armillaria root disease in juvenile coniferous stands in the southern interior of British Columbia

2000 ◽  
Vol 30 (3) ◽  
pp. 405-414 ◽  
Author(s):  
D J Morrison ◽  
K W Pellow ◽  
D J Norris ◽  
A FL Nemec
Keyword(s):  
British Columbia ◽  
Host Response ◽  
Root Disease ◽  
Host Reaction ◽  
Intensity Of Infection ◽  
Climatic Regions ◽  
Forest Region ◽  
Armillaria Root Disease ◽  
The Relationship ◽  
Actual Incidence

The relationship between aboveground symptoms and belowground incidence of Armillaria ostoyae (Romagn.) Herink on conifers in 13- to 24-year-old stands was investigated at five sites in each of the dry, moist, and wet climatic regions in the Nelson forest region, British Columbia. All trees >1.3 m in height in 0.01-ha circular plots centred on a tree killed fewer than two or more than five years previously or located where there were no symptomatic trees were removed from the soil by an excavator. The location and host response at each A. ostoyae lesion on root systems were recorded. Significant differences in belowground incidence were seen among climatic regions and plot types, with distance from the centre of plots, and between planted and naturally regenerated trees. Belowground incidence was related to the percentage of putatively colonized stumps within and adjacent to plots. There were significant differences among climatic regions in the intensity of infection, host reaction to infection, and percentage of diseased trees showing aboveground symptoms. These results have implications for interpreting results of surveys for Armillaria root disease in juvenile stands and for tending of such stands.

Early infection of Merluccius productus (Ayres) (Pisces: Teleostei) with Kudoa thyrsites (Gilchrist) (Myxozoa)

1987 ◽  
Vol 65 (4) ◽  
pp. 936-939 ◽  
Author(s):  
D. J. Whitaker ◽  
Z. Kabata
Keyword(s):  
Water Column ◽  
Muscle Fibre ◽  
High Intensity ◽  
Host Response ◽  
Early Infection ◽  
Host Reaction ◽  
Intensity Of Infection ◽  
Merluccius Productus ◽  
Kudoa Thyrsites ◽  
Three Stages

Within 5 months of metamorphosis, age 0+ Pacific hake (Merluccius productus) became infected with the myxozoan muscle parasite Kudoa thyrsites. Prevalence and intensity of infection increased with time. Approximately 4 months after the parasite had become established in a muscle fibre, a host response was initiated, which rapidly destroyed it. Three stages of host response were recognized depending on the extent of the host reaction. The prevalence and intensity of infections showing a host response also increased with time. The possibility of a fish developing high intensity infections by ingesting spores from the water column is discussed.

scholarly journals Assessment of armillaria root disease infection in stands in south-central British Columbia with varying levels of overstory retention, with and without pushover logging

2011 ◽  
Vol 41 (8) ◽  
pp. 1598-1605 ◽  
Author(s):  
William K. Chapman ◽  
Bruce Schellenberg ◽  
Teresa A. Newsome
Keyword(s):  
British Columbia ◽  
Tree Mortality ◽  
Root Disease ◽  
Thuja Plicata ◽  
South Central ◽  
Partial Harvesting ◽  
Armillaria Root Disease ◽  
Mean Differences ◽  
Removal Technique ◽  
Thuja Plicata Donn

This trial, conducted near Nakusp, British Columbia, compares pushover logging (combination tree felling and root removal technique using large machines to push trees out of the ground) with handfalling logging (no root removal) for effects on the incidence of armillaria root disease in postharvest regeneration. Pushover logging did not reduce levels of root disease, expressed as percentage tree mortality, over handfalling harvesting on this site. High variability of measured disease levels within some treatments and few replicates lowered the power of the trial. However, in addition to being statistically insignificant, the mean differences between the two main treatments were small and biologically uninteresting, and the response was inconsistent in direction. The trial also included three mature timber retention levels as treatments, and there seemed to be a trend of declining root disease with increased retention of stems. This phenomenon should be further investigated as current literature is not clear on the response of armillaria to partial harvesting. There was a strong suggestion of a difference between susceptibility of natural and planted seedlings to armillaria root disease, with natural regeneration being less susceptible. Thuja plicata Donn ex D. Don was less affected by armillaria root disease than other species in this trial, whether it was planted or naturally regenerated.

Effects of selective cutting on the epidemiology of armillaria root disease in the southern interior of British Columbia

2001 ◽  
Vol 31 (1) ◽  
pp. 59-70 ◽  
Author(s):  
D J Morrison ◽  
K W Pellow ◽  
A FL Nemec ◽  
D J Norris ◽  
P Semenoff
Keyword(s):  
Host Response ◽  
Root Systems ◽  
Root Disease ◽  
Selective Cutting ◽  
Tree Diameter ◽  
Armillaria Ostoyae ◽  
Primary Roots ◽  
Armillaria Root Disease ◽  
Mature Stands ◽  
Tree Condition

In selectively cut and undisturbed parts of four mature stands, five 0.04-ha plots were established, and trees were measured, mapped, and examined for aboveground symptoms of armillaria root disease. Trees were felled, and stumps and their root systems were removed by an excavator and were measured and examined for Armillaria lesions. Isolates from root lesions, rhizomorphs associated with lesions, and basidiomes collected in or adjacent to plots were of Armillaria ostoyae (Romagn.) Herink. All trees were assigned to one of five tree condition classes based on the location of lesions and host response. The merchantable volume in each class was calculated. In undisturbed plots, incidence of trees with A. ostoyae lesions on roots was about 10% in the dry climatic region compared with about 75% in the moist region and 35% in the wet region. In plots in the selectively cut parts of the stands, 50-100% of stumps were colonized by A. ostoyae. Results of a logistic regression analysis showed that selective cutting was associated with a statistically significant increase in the probability of a tree having A. ostoyae lesions, where the magnitude of the increase depended on tree diameter. The increase in the probability of a tree being diseased was accompanied by an increase in the proportion of primary roots with lesions and the average number of lesions per diseased tree; however, the increases in disease intensity were statistically significant at only two (one dry and one moist) of the four sites. The percentage of merchantable volume threatened or killed by A. ostoyae was usually higher in cutover than undisturbed plots.

scholarly journals An exploration of ringbarking to reduce the severity of Armillaria root disease in logged areas in British Columbia

2015 ◽  
Vol 45 (12) ◽  
pp. 1803-1805 ◽  
Author(s):  
Bill Chapman ◽  
Bruce Schellenberg
Keyword(s):  
British Columbia ◽  
Pseudotsuga Menziesii ◽  
Tree Mortality ◽  
Timber Harvesting ◽  
Douglas Fir ◽  
Root Disease ◽  
The World ◽  
Armillaria Root Disease ◽  
Severity Of The Disease

Ringbarking is a girdling technique that is used prior to timber harvesting to reduce losses to Armillaria root disease in some parts of the world. The technique had not previously been evaluated in British Columbia, Canada. Small plots of primarily Douglas-fir (Pseudotsuga menziesii (Mirb.) Franco) trees that were ringbarked prior to timber harvesting had approximately 50% lower levels of Armillaria root disease caused tree mortality in young trees after 15 years than plots of trees that were not ringbarked. Ringbarking did not reduce Armillaria root disease in this trial as much as has been reported in other research. This could be attributable to the centre of the small plots being within 5–10 m of live and dead Armillaria-infected trees in the surrounding forest. The treatment did reduce the severity of the disease by both statistically and biologically significant amounts and, therefore, warrants further investigation as a possible treatment where timber harvesting is conducted in Armillaria root disease affected stands.

scholarly journals Annual Spread Rate of Tomentosus Root Disease

Plant Disease ◽  
1997 ◽  
Vol 81 (9) ◽  
pp. 1053-1056 ◽  
Author(s):  
R. S. Hunt ◽  
F. G. Peet
Keyword(s):  
British Columbia ◽  
Tree Ring ◽  
Root Disease ◽  
Uninfected Control ◽  
Radial Increment ◽  
Spread Rate ◽  
Annual Increment ◽  
Temporal Differences ◽  
The Difference ◽  
A New Technique

The spread rate of tomentosus root disease, caused by Inonotus tomentosus, was investigated by a new technique employing temporal differences in the initiation of the reduced annual radial increment between pairs of diseased trees. Pairs of infected trees (stumps) located on the periphery of disease centers were selected in each of six widely separated spruce (Picea spp.) stands in British Columbia. Distances between 12 pairs of stumps were measured, and disks were collected from each stump. Similarly, disks from four additional pairs were collected from trees in a younger stand. Uninfected control disks were collected for all sites. Tree-ring measurements were determined for all disk samples and the year in which the reduction of the annual increment attributable to I. tomentosus began was determined for infected trees. The difference between initiation years for pairs of infected trees divided into the distance between them produced an average annual spread rate of 20 cm/yr. This rate will be used in developing a model for the disease.

scholarly journals Landslides in weakly cemented glaciolacustrine sediments, Morkill River valley, British Columbia

2001 ◽  
Vol 38 (4) ◽  
pp. 889-900 ◽  
Author(s):  
Corey R Froese ◽  
David M Cruden
Keyword(s):  
British Columbia ◽  
River Valley ◽  
Carbonate Content ◽  
Canadian Rocky Mountains ◽  
Density Profiles ◽  
Frost Action ◽  
Dominant Component ◽  
Freeze And Thaw ◽  
Calcite Cement ◽  
The Relationship

Slopes in weakly cemented glaciolacustrine sediments in the Morkill River valley in the Canadian Rocky Mountains stand at up to 70°. Based on field and laboratory observations it appears that a contributing factor to instability is the softening of the soils by frost action and the leaching of calcite cement. Field density profiles demonstrated increased density and carbonate content with an increase in depth. Laboratory tests of carbonate content indicated a positive correlation between calcium carbonate and density in the glaciolacustrine sediments. The relationship was strongest in sands, in which leaching and dissolution were important components of softening. In clays, frost action was the dominant component of softening. Freeze-thaw tests showed a 50% decrease in strength after one cycle of freeze and thaw in the silts and clays.Key words: landslide, cemented, glaciolacustrine sediments, British Columbia.

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