Incidence of Armillaria species in precommercial thinning stumps and spread of Armillaria ostoyae to adjacent Douglas-fir trees

1997 ◽  
Vol 27 (4) ◽  
pp. 481-490 ◽  
Author(s):  
M G Cruickshank ◽  
D J Morrison ◽  
Z K Punja
2019 ◽  
Vol 49 (7) ◽  
pp. 767-774
Author(s):  
Stefan Zeglen ◽  
Paul J. Courtin

Mechanized treatment for root diseases such as Coniferiporia sulphurascens (Pilát) L. W. Zhou & Y. C. Dai (syn. Phellinus sulphurascens Pilát) and Armillaria ostoyae (Romagn.) Herink (syn. Armillaria solidipes Peck) is often avoided due to cost or the perception that removal of stumps creates detrimental soil disturbance or degradation that hinders site productivity. Our study tested five diseased stands that were treated by extracting stumps following harvesting and replanted with susceptible Douglas-fir. Soil disturbance surveys were conducted in treated and untreated plots, and individual planted spots were assessed and categorized for soil disturbance using existing and proposed new categories specific to disturbance caused by the stump removal. Tree measurements were taken at intervals over the first 10 years of stand development, and foliage was sampled for nutrient analysis. The percentage of total and counted disturbance was 20%–46% and 8%–11% greater, respectively, in treated versus untreated plots; however, mean tree growth in height and diameter was not statistically different between treatments and was more positive for treated plots at all sites but one. Tree nutrition and survival to age 10 was not negatively affected by stump removal. Total site productivity represented by basal area and tree volume differed widely between sites but was not significantly different between treatments.


1983 ◽  
Vol 13 (6) ◽  
pp. 1246-1248 ◽  
Author(s):  
Douglas A. Maguire

A densely regenerated Douglas-fir (Pseudotsugamenziesii (Mirb.) Franco) plantation in northern California was precommercially thinned from approximately 15 000 stems/ha to 740 stems/ha. Trees in an unthinned strip served as control for analyzing thinning responses. The terminal and lateral leader growth of "released" trees were significantly reduced after thinning, but the number of buds was significantly increased.


2003 ◽  
Vol 33 (4) ◽  
pp. 612-623 ◽  
Author(s):  
B A Ferguson ◽  
T A Dreisbach ◽  
C G Parks ◽  
G M Filip ◽  
C L Schmitt

The coarse-scale population structure of pathogenic Armillaria (Fr.) Staude species was determined on approximately 16 100 ha of relatively dry, mixed-conifer forest in the Blue Mountains of northeast Oregon. Sampling of recently dead or live, symptomatic conifers produced 112 isolates of Armillaria from six tree species. Armillaria species identifications done by using a polymerase chain reaction based diagnostic and diploid–diploid pairings produced identical results: 108 of the isolates were Armillaria ostoyae (Romagn.) Herink and four were North American Biological Species X (NABS X). Five genets of A. ostoyae and one of NABS X were identified through the use of somatic incompatibility pairings among the putatively diploid isolates. Armillaria ostoyae genet sizes were approximately 20, 95, 195, 260, and 965 ha; cumulative colonization of the study area was at least 9.5%. The maximum distance between isolates from the 965-ha A. ostoyae genet was approximately 3810 m, and use of three estimates of A. ostoyae spread rate in conifer forests resulted in age estimates for the genet ranging from 1900 to 8650 years. Results are discussed in relation to possible mechanisms that influenced the establishment, expansion, and expression of these genets; the genetic structure and stability of Armillaria; and the implications for disease management in this and similar forests.


2010 ◽  
Vol 40 (1) ◽  
pp. 155-166 ◽  
Author(s):  
M. G. Cruickshank ◽  
B. Jaquish ◽  
A. F.L. Nemec

The objectives of this study were to (i) develop a methodology for screening conifer seedlings for resistance to Armillaria ostoyae (Romagn.) Herink and (ii) screen a population of interior Douglas-fir ( Pseudotsuga menziesii var. glauca (Biessn.) Franco) population for resistance to A. ostoyae. Eighteen potted seedlings from each of 86 half-sib interior Douglas-fir families were challenged with inoculum in a 3-year greenhouse trial. The seed originated from four geographically distinct tree breeding zones that represent physically and biologically different environments in southeastern British Columbia. Mortality and the final percent survival of inoculated trees showed differences among the families (survival range 0%–61.1%) and breeding zones (survival range 6.6%–25.3%). Maximum heritability index (0.19) occurred at 28 months. Survival analyses revealed that most of the differences in survival could be explained by the zone from which the family originated. The less susceptible seedlings originated from the drier and warmer zones and limited the spread of the fungus in the root system. Moderate levels of family variation in resistance to A. ostoyae and low-moderate heritability suggest that, in interior Douglas-fir, gains in resistance can be achieved through breeding.


2004 ◽  
Vol 34 (6) ◽  
pp. 1210-1219 ◽  
Author(s):  
Daniel W Omdal ◽  
Charles G Shaw, III ◽  
William R Jacobi

Crown symptoms and other aboveground variables were examined on 36 Douglas-fir (Pseudotsuga menziesii (Mirb.) Franco.) (40–209 years old), 46 white fir (Abies concolor (Gord. & Glend.) Lindl.) (36–165 years old), and 97 ponderosa pine (Pinus ponderosa Dougl. ex Laws.) (64–220 years old) trees in northern New Mexico and southern Colorado. Root systems of all trees were excavated to determine extent of root disease. Symptoms observed on infected trees, including reductions in height growth, changes in foliage characteristics, and crown dieback, worsened as the number of infected roots increased. Trees with aboveground symptoms had a significantly higher (p < 0.05) number of infected lateral roots than trees without symptoms. In mixed conifer stands on the Archuleta Mesa, Colo., four qualitative crown symptoms were used to accurately detect Armillaria ostoyae (Romagn.) Herink and (or) Heterobasidion annosum (Fr.) Bref. infection of Douglas-fir (21/22, or 95%) and white fir (19/28, or 68%). Similarly, 61% (48/79) of the A. ostoyae infected ponderosa pine trees on the Jemez site, N.M., were detected using the qualitative Thomson vigor rating system. Discriminate analysis, using more thorough variables and analysis, resulted in correct infection classifications of 82%, 85%, and 78% for Douglas-fir, white fir, and ponderosa pine, respectively, suggesting that aboveground variables are reasonable indicators of root disease.


2008 ◽  
Vol 38 (6) ◽  
pp. 1564-1575 ◽  
Author(s):  
David G. Briggs ◽  
Rapeepan Kantavichai ◽  
Eric C. Turnblom

The effect of precommercial thinning in 6- to 13-year-old Douglas-fir ( Pseudostuga menziesii (Mirb.) Franco var. menziesii ) plantations with and without fertilization with 224 kg·ha–1 nitrogen (N) as urea on the mean diameter of the largest limb at breast height (DLLBH) was modeled. DLLBH is a simple, nondestructive field measurement related to log knot indices used to measure log quality in product recovery studies. Model [1] succeeded in predicting mean DLLBH (RMSE = 2.80 and radj2 = 0.84) using only site, initial stocking, and treatment variables. Model [2], which used only mean tree variables, improved on model [1] and was simpler. However, model [3], which used a combination of both groups of variables, produced the best model. Model [4] successfully predicted mean DLLBH using variables that can be measured with light detection and ranging (LIDAR), a high-resolution remote sensing technology. Since the age when the live crown receded above breast height is an important variable in some of the models, model [5] was developed to predict when crown recession above breast height occurs. This study found that mean DLLBH of Douglas-fir plantations can be estimated using variables obtained from stand-level growth models or remote sensing, providing a quality indicator that can be easily measured and verified in the field.


2000 ◽  
Vol 30 (3) ◽  
pp. 507-512 ◽  
Author(s):  
Jean A Bérubé

Crosses with standard testers were used to identify 96 haploid Armillaria isolates from 34 collections made in Newfoundland. Isoenzyme patterns were also used to identify 36 diploid and 3 haploid Armillaria isolates from 39 other collections. Diagnostic electromorphs at Rf 0.70 for esterases, Rf 0.32 for succinate dehydrogenase, and Rf 0.31 for 6-phosphogluconate dehydrogenase permitted positive identification of Armillaria ostoyae (Romagn.) Herink for all isolates tested by electrophoresis, and the method worked with haploid and diploid isolates. Crosses of the 96 haploid isolates collected on hardwoods and conifers were all positive for A. ostoyae, except for eight isolates. These eight isolates from three collections made on or near an American mountain-ash (Sorbus americana Marsh.) in a St. John's city park, where numerous exotic tree species are present, were found to be Armillaria sinapina Bérubé & Dessureault. These isolated collections in an area of limited natural hardwood presence may be the result of an introduction from the mainland; thus, A. ostoyae appears to be the only Armillaria species found in natural habitats in Newfoundland.


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