scholarly journals The relationship between climate and outbreak dynamics of Dothistroma needle blight in northwest British Columbia, Canada.

2007 ◽  
Author(s):  
Cedar Welsh
2010 ◽  
Vol 86 (4) ◽  
pp. 412-422 ◽  
Author(s):  
Alex J. Woods ◽  
Don Heppner ◽  
Harry H. Kope ◽  
Jennifer Burleigh ◽  
Lorraine Maclauchlan

BC’s forests have already faced two simultaneous, globally significant, epidemics linked to climate change; the Dothistroma needle blight epidemic in NW BC and the massive mountain pine beetle epidemic throughout the BC Interior. Building on these experiences, we have compiled our best estimates of how we believe other forest health agents may behave as climate change continues to influence our forests. We have drawn on literature from around the world but have focused on the situation in BC. We have made management recommendations based on what we have seen so far and what we expect to come.Key words: climate change, forest health, forest insects, forest pathogens, forest management, British Columbia


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


1966 ◽  
Vol 42 (2) ◽  
pp. 160-161 ◽  
Author(s):  
A. K. Parker ◽  
D. G. Collis

2009 ◽  
Vol 39 (12) ◽  
pp. 2505-2519 ◽  
Author(s):  
Cedar Welsh ◽  
Kathy Lewis ◽  
Alex Woods

Native pathogens are normally limited in the damage they cause by host resistance and (or) environmental conditions that limit one or more phases of the disease cycle. Changes to host or environmental conditions can relax these limits and result in disease emergence. Until recently, Dothistroma needle blight (Dothistroma), caused by Dothistroma septosporum (Dorog.) Morelet, has had only minor impacts on native forest trees in western North America. Over the past decade in the forests of northwestern British Columbia, Canada, Dothistroma has caused extensive mortality in managed plantations of lodgepole pine ( Pinus contorta Dougl. ex Loud. var. latifolia Engelm.), and even mature pine trees are succumbing. We used dendrochronological techniques to reconstruct the temporal patterns of past Dothistroma outbreaks in the area using tree-ring series from sites with documented outbreaks. We found that Dothistroma outbreaks in northwest British Columbia have occurred periodically over the last 174 years, with an increase in outbreak incidence and extent since the 1940s. The most distinct change observed in the outbreak history has been the greater severity and synchrony among the sites affected during the current outbreak. A recently observed climate change trend over the study area may represent an environmental trigger that synchronized the current outbreak causing the widespread emergence of the disease.


2020 ◽  
Author(s):  
Arnaud Capron ◽  
Nicolas Feau ◽  
Renate Heinzelmann ◽  
Irene Barnes ◽  
Andy Benowicz ◽  
...  

Many current tree improvement programs are incorporating assisted gene flow strategies to match reforestation efforts with future climates. This is the case for the lodgepole pine (Pinus contorta var. latifolia), the most extensively planted tree in western Canada. Knowledge of the structure and origin of pathogen populations associated with this tree would help improve the breeding effort. Recent outbreaks of the Dothistroma needle blight (DNB) pathogen Dothistroma septosporum on lodgepole pine in British Columbia and its discovery in Alberta plantations raised questions about the diversity and population structure of this pathogen in western Canada. Using genotyping-by-sequencing (GBS) on 119 D. septosporum isolates from 16 natural pine populations and plantations from this area, we identified four genetic lineages, all distinct from the other DNB lineages from outside of North America. Modeling of the population history indicated that these lineages diverged between 31.4 and 7.2k years ago, coinciding with the last glacial maximum and the post-glacial recolonization of lodgepole pine in western North America. The lineage found in the Kispiox Valley from British Columbia, where an unprecedented DNB epidemic occurred in the 1990s, was close to demographic equilibrium and displayed a high level of haplotypic diversity. Two lineages found in Alberta and Prince George (British Columbia) showed departure from random mating and contemporary gene flow, likely resulting from pine breeding activities and material exchanges in these areas. The increased movement of planting material could have some major consequences by facilitating secondary contact between genetically isolated DNB lineages, possibly resulting in new epidemics.


2020 ◽  
Vol 47 (2) ◽  
pp. 144-152
Author(s):  
Emília Ondrušková ◽  
Radovan Ostrovský ◽  
Zuzana Jánošíková ◽  
Katarína Adamčíková ◽  
Marek Kobza

AbstractDothistroma needle blight (DNB) is a disease of pine needles. It causes significant defoliation of affected trees; intensive attacks lead to damages of the whole stand. The relationship of trends in disease severity and intensity with climatic variables were studied in three Austrian pine plantations (Jahodná, Kálnica, Litava) during 2014–2018. During the monitoring period, the greatest variability in disease severity was observed in the top third of the crowns, which showed the highest correlation with the variants of the most important climatic conditions (temperature and relative humidity) tested. For the spread of DNB, based on statistical assessment, a higher number of intervals of environmentally favourable climatic conditions is crucial. Both Dothistroma species (D. septosporum and D. pini), which are causal agents of the disease, were identified in Jahodná. In Kálnica and Litava, only D. septosporum was present.


2014 ◽  
Vol 44 (3) ◽  
pp. 212-219 ◽  
Author(s):  
Cedar Welsh ◽  
Kathy J. Lewis ◽  
Alex J. Woods

Dothistroma needle blight (DNB) has caused extensive mortality in plantations of lodgepole pine in northwestern British Columbia, Canada, and even mature pine trees in natural forests are succumbing. We examined a number of explanatory models to determine which temperature or precipitation variable is most important in explaining DNB outbreak occurrence. We compared a multicentury tree-ring outbreak reconstruction with mean monthly temperature and total monthly precipitation during the individual and seasonal spring (April, May, June) and summer (July, August, September) months. A trend towards increased August minimum temperatures appears to be an important climate factor contributing to the spread of the disease. Graphical comparisons of total April precipitation reveal that periods of above-average precipitation coincided with periods of outbreak increase. Decreases in August minimum temperature also correspond to decreases in outbreak severity. Even more pronounced was a spike in spring precipitation and its association with the current epidemic. The correspondence of past outbreaks with periods of wet and warm conditions suggests that regional climate trends drive DNB behavior. The extent and severity of the current disease epidemic raises the possibility that the key factors that drive outbreaks have become more frequent, enabling the emergence of DNB as a serious disease.


2021 ◽  
Vol 7 (2) ◽  
pp. 111
Author(s):  
Martin S. Mullett ◽  
Rein Drenkhan ◽  
Kalev Adamson ◽  
Piotr Boroń ◽  
Anna Lenart-Boroń ◽  
...  

Dothistroma septosporum, the primary causal agent of Dothistroma needle blight, is one of the most significant foliar pathogens of pine worldwide. Its wide host and environmental ranges have led to its global success as a pathogen and severe economic damage to pine forests in many regions. This comprehensive global population study elucidated the historical migration pathways of the pathogen to reveal the Eurasian origin of the fungus. When over 3800 isolates were examined, three major population clusters were revealed: North America, Western Europe, and Eastern Europe, with distinct subclusters in the highly diverse Eastern European cluster. Modeling of historical scenarios using approximate Bayesian computation revealed the North American cluster was derived from an ancestral population in Eurasia. The Northeastern European subcluster was shown to be ancestral to all other European clusters and subclusters. The Turkish subcluster diverged first, followed by the Central European subcluster, then the Western European cluster, which has subsequently spread to much of the Southern Hemisphere. All clusters and subclusters contained both mating-types of the fungus, indicating the potential for sexual reproduction, although asexual reproduction remained the primary mode of reproduction. The study strongly suggests the native range of D. septosporum to be in Eastern Europe (i.e., the Baltic and Western Russia) and Western Asia.


2001 ◽  
Vol 38 (4) ◽  
pp. 889-900 ◽  
Author(s):  
Corey R Froese ◽  
David M Cruden

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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