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

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.

2015 ◽  
Vol 45 (12) ◽  
pp. 1803-1805 ◽  
Author(s):  
Bill Chapman ◽  
Bruce Schellenberg

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.


2003 ◽  
Vol 79 (5) ◽  
pp. 892-897 ◽  
Author(s):  
Alex J Woods

Forest management in the Interior Cedar Hemlock (ICH) zone of the Kispiox TSA in northwest British Columbia has focused on two tree species. Interior spruce (Picea engelmanni Parry ex Engelm. × Picea glauca (Moench) Voss) and lodgepole pine (Pinus contorta var. latifolia Dougl. ex Loud.) have dominated plantations, while historically, western hemlock (Tsuga heterophylla (Raf.) Sarg.), true firs (Abies lasiocarpa (Hook.) Nutt. and (Abies amabilis (Dougl. ex Loud.) Dougl. ex Forbes) and western redcedar (Thuja plicata Donn ex D. Don), have dominated the landscape. Tomentosus root disease (Inonotus tomentosus (Fr.) Teng) and Dothistroma needle blight (Mycosphaerella pini Rostr. in Munk) are the principal diseases affecting interior spruce and lodgepole pine plantations, respectively. Tomentosus root disease was found in 92% of spruce-dominated stands 100 years and older in the study area. The annual recruitment of dead interior spruce and lodgepole pine tree volume due to the disease in those stands is 4.29 m3/ha or 51 990 m3. The incidence of Tomentosus root disease in ten randomly selected spruce leading plantations aged 25–30 years ranged from 0.6% to 10.4% and averaged 5.9% of the host trees. Dothistroma needle blight was the most prevalent pest in a survey of 100 randomly selected lodgepole pine plantations and has caused considerable crop tree mortality. The disease has even caused mortality in 55-year-old lodgepole pine trees. Maintaining species diversity is essential to long-term forest health. Intensive planting of interior spruce and lodge-pole pine in this study area appears to have exacerbated disease problems. Key words: forest health, species diversity, interior spruce, lodgepole pine, Tomentosus root disease, Dothistroma needle blight


2012 ◽  
Vol 27 (1) ◽  
pp. 25-29 ◽  
Author(s):  
Charles G. Shaw ◽  
D.W. Omdal ◽  
A. Ramsey-Kroll ◽  
L.F. Roth

Abstract A stand of ponderosa pine (Pinus ponderosa) severely affected by Armillaria root disease was treated with five different levels of sanitation by root removal to reduce root disease losses in the regenerating stand. Treatments included the following: (1) all trees pushed over by machine, maximum removal of roots by machine ripping, and visible remaining roots removed by hand; (2) all trees pushed over by machine and maximum removal of roots by machine ripping; (3) all trees pushed over by machine with no further removal of roots; (4) smaller trees pushed over by machine but large stumps left, otherwise maximum removal of roots by machine ripping; and (5) all trees felled and removed by skidding, area cleared of slash, sod scalped, and no removal of roots. After 35 years, we found that the more intense and thorough root-removal treatments were generally more effective in reducing the occurrence of Armillaria root disease. However, even the most intensive treatment (treatment 1), which experienced significantly less disease than most other treatments, had 23% of the area expressing mortality. The only operationally feasible treatment (treatment 3) also reduced levels of mortality, but not significantly (40% mortality versus 52% in the control, treatment 5). Although these results support the concept that inoculum removal can reduce root disease levels, the treatment necessary to provide a meaningful reduction in disease loss does not seem to warrant its cost.


1999 ◽  
Vol 14 (3) ◽  
pp. 144-148 ◽  
Author(s):  
Gregory M. Filip ◽  
Stephen A. Fitzgerald ◽  
Lisa M. Ganio

Abstract A 30-yr-old stand of ponderosa pine was precommercially thinned in 1966 to determine the effects of thinning on tree growth and mortality caused by Armillaria root disease in central Oregon. After 30 yr, crop tree mortality was significantly (P = 0.02) less in thinned plots than in unthinned plots. Tree diameter growth was not significantly (P = 0.17) increased by thinning. Crop-tree basal area/ac growth was significantly (P = 0.03) greater in thinned plots. Apparently, from a root disease perspective, precommercial thinning of pure ponderosa stands significantly decreases the incidence of crop-tree mortality after 30 yr and significantly increases basal area/ac growth but not individual tree diameter growth. Recommendations for thinning based on stand density index (SDI) are given. West. J. Appl. For. 14(3):144-148.


1989 ◽  
Vol 4 (2) ◽  
pp. 58-59 ◽  
Author(s):  
Gregory M. Filip ◽  
Donald J. Goheen ◽  
David W. Johnson ◽  
John H. Thompson

Abstract A naturally regenerated stand of ponderosa pine (Pinus ponderosa) was thinned in 1966 to determine the effects of spacing on crop-tree mortality caused by Armillaria root disease in central Oregon. After 20 years, crop-tree mortality in unthinned plots exceeded that in the thinned plots (1.6 vs. 0.8 trees/ac/yr). Crop-tree diameter growth, however, was greater in thinned plots (0.2 vs. 0.1 in./yr). Forest managers should not defer thinning of similar stands because of Armillaria root disease. West J. Appl. For. 4(2):58-59, April 1989.


2000 ◽  
Vol 15 (2) ◽  
pp. 92-100 ◽  
Author(s):  
Lewis F. Roth ◽  
Charles G. Shaw ◽  
Leonard Rolph

Abstract A stand of ponderosa pine (Pinus ponderosa) severely impacted by Armillaria root disease was treated with five different levels of sanitation by root removal in an attempt to reduce losses to root disease in the regenerating stand. Treatments included: (1) Trees pushed out, maximum removal of roots by machine, visible remaining roots picked out by hand; (2) Trees pushed out, maximum removal of roots by machine; (3) Trees pushed out, no further removal of roots; (4) Trees pushed out, large stumps left, otherwise maximum removal of roots by machine; (5) Clear logged, sod scalped between the stumps, stumps retained. After 20 yr there was a general reduction in mortality with improved sanitation, although treatment #3 was less effective than expected. In each type of stand regeneration (thinned, unthinned, and planted), only treatment #1 consistently expressed less mortality than the other treatments, and differences were significant in the thinned and unthinned portions of the experiment between treatments #1 and #5. Crop tree height and diameter growth after 20 yr were also best in treatment #1. These results do not necessarily indicate that push-over logging is ineffective, but rather they show that after trees and intact stumps have been pushed out, further cleaning is needed to reach the satisfactory sanitation level achieved in treatment #1. Hand cleaning as done in treatment #1 would certainly be cost prohibitive, but perhaps that level of root removal could be achieved in light textured soils with judicious use of a land-clearing brush rake. West. J. Appl. For. 15(2):92-100.


2009 ◽  
Vol 24 (2) ◽  
pp. 88-94 ◽  
Author(s):  
Gregory M. Filip ◽  
Stephen A. Fitzgerald ◽  
Kristen L. Chadwick ◽  
Timothy A. Max

Abstract Portions of a 30-year-old stand of ponderosa pine were precommercially thinned in 1966 and commercially thinned in 2000 at age 64 years to determine the effects of thinning from below on tree growth and mortality caused by Armillaria root disease in central Oregon. Thirty years after precommercial thinning, leave-tree mortality was significantly less in thinned plots than in unthinned plots, but leave-treeߝdiameter growth was not significantly increased by thinning. Leave-tree basal area (BA) per acre growth, however, was significantly greater in thinned plots.In 2007 at age 71 years, 7 years after commercial thinning of the same plots that were precommercially thinned in 1966, leave-tree mortality was less in thinned plots than in unthinned plots, but more time probably is necessary to adequately assess Armillaria-caused mortality after commercial thinning. Both tree diameter and BA growth were significantly increased by commercial thinning. Hypotheses on fungal-host dynamics are discussed, and recommendations for multiple thinning based on stand density index are given.


2004 ◽  
Vol 34 (8) ◽  
pp. 1730-1746 ◽  
Author(s):  
Taro Asada ◽  
Barry G Warner ◽  
Allen Banner

Sphagnum invasion 8 years after an experimental clear-cut and mounding field trial was examined in a mesic western redcedar (Thuja plicata Donn ex D. Don) – western hemlock (Tsuga heterophylla (Raf.) Sarg.) forest on the outer north coast of British Columbia. Sphagnum invasion was prominent in wet hollows in the mounded blocks. Pioneer species, Sphagnum pacificum Flatb. and Sphagnum angustifolium (C. Jens. ex Russ.) C. Jens., were common despite being minor components in the precut forest. Sphagnum girgensohnii Russ., a species of forests, showed expanding colonies and contained some Sphagnum capillifolium (Ehrh.) Hedw. Comparisons of vertical growth and decomposition rates of Sphagnum in the experimental field site and in a nearby natural peatland suggest that peat accumulation potential in the Sphagnum colonies in the mounded blocks is similar to that in the natural peatland. These observations suggest that open peatland-type plant communities become established and paludification processes are beginning. Mounding may be an effective strategy for silvicultural management to improve tree growth in the short term but may initiate paludification and negatively impact forest productivity in the long term in hypermaritime lower productivity forests.


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