Red band needle blight is an economically important forest disease which causes serious defoliation of many coniferous trees, particularly pine when planted out of their native range (Bradshaw 2004). The fungus responsible for the disease, Dothistroma septospora (Dorog.) Morelet infects the needles, leading to necrotic lesions, needle death and reduced wood yield. Premature defoliation caused by this fungus has resulted in complete failure of many exotic pine plantations in New Zealand, South Africa and South America. Monterey pine plantations on the west coast of North America have also been severely damaged, but the disease is not found in natural stands of this species (Patton 1997), and until recently has been uncommon and little concern in natural stands of other hard pine species of western North America. An outbreak of Dothistroma is taking place in the Interior Cedar Hemlock zone (ICH) east of the coast range in northern British Columbia where climate is characterized by a warm and humid coastal weather system. Disease development and subsequent effects are highly dependent on weather conditions. The current outbreak in northwestern British Columbia is thought to be due in part to weather patterns that have become more conductive to the spread of the fungus: mild summer temperatures and prolonged periods of high humidity or leaf surface water films. Results of both ground and aerial surveys have shown successive increases in the extent and severity of the Dothistroma epidemic in lodgepole pine-leading stands. Evidence of 55-year-old natural stands of lodgepole pine during the survey were also observed to have >20% tree mortality as a result of Dothistroma (Woods 2003). Dothistroma poses a significant threat to the growth and yield of lodgepole pine in northwestern British Columbia. The current outbreak in British Columbia is much larger than what has been observed in the recorded past. Weather in the past decade appear to be changing resulting in frequent episodes of warm rain during summer months. In order to avoid future epidemics, and to develop comprehensive strategies for management of lodgepole pine, it is critical that the impacts of climate and weather patterns on disease severity of Dothistroma are understood. This project fits with latest strategic goals of the Forest Sciences Program, specifically in the Program: Timber Growth and Value, and the Theme: Timber Losses to Environmental Factors. The main objective of this project is to determine the influence of weather patterns on the extent and nature of current and historic disease severity to understand the spatial and temporal variations of the outbreaks. A second objective is to analyze the distribution of current and past disease outbreaks with respect to changes in host abundance due to forest management. Methods: Spore traps and simple weather stations will be identified or established in approximately 10 locations in the Interior Cedar Hemlock (ICH) zone and the Sub-boreal Spruce zone (SBS) within the affected area. These will be monitored on a regular basis to determine weather conditions that are conducive to spore production. Documented past outbreaks of D. septospora will be used to develop a dendrochronological signal that can be used to look back in time through the tree-ring record, in order to identify pre-record defoliation events. Climate reconstruction will be used to determine pre-record weather conditions and these will be correlated with past outbreaks. Within the region currently affected by Dothistroma, approximately 30 sites in northwestern British Columbia will be studied. Half of the study sites will be used to reconstruct and compare historic outbreaks of Dothistroma and historic climate. The remaining half will be used to study the influence of local weather patterns on current disease severity as it varies with topographic features. Sites for dendrochronological analyses will be selected based on the following criteria: <30km ...
Lewis, Kathy J.. 2007. Relationships between climate, forest practices and incidence of Dothistroma needle blight septosporum. Forest Investment Account (FIA) - Forest Science Program. Forest Investment Account Report. FIA2007MR442
Topic: FLNRORD Research Program
Keywords: Forest, Investment, Account, (FIA), Dothistroma, Pini, Dothistroma, Pini, effect, climate, on, Pinus, Diseases, Pests, Vegetation, Climate, British, Columbia
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