Current Research Interests
I am a forester from British Columbia, Canada with an expertise in Forest Pathology. I am currently working on the emerging invasive disease causing dieback of common ash (Fraxinus excelsior) throughout central, eastern and northern Europe. My research focuses on better understanding the early infection stages and the general infection biology of Hymenoscyphus pseudoalbidus (anamorph = Chalara fraxinea) and disease development within the host using histological techniques for fluorescence and scanning electron microscopy.
Apothecia of H. pseudoalbidus on petioles of F. excelsior.
|I am also interested in understanding the non-specific defense responses in F. excelsior and those induced in response to H. pseudoalbidus and the less aggressive H. albidus. Work in collaboration with tree breeders at Skogforsk has shown large variation in genotypic expression of resistance in F. excelsior against C. fraxinea. We are currently conducting field and greenhouse tests on this clonal material to understand the mechanisms of resistance operating in susceptible and more resistant clones to facilitate selection more resistant ash genotypes for future tree breeding.
Diseased shoots of F. excelsior.
From 2006-2010, I was employed as a forest pathologist with the government of British Columbia in Canada where I worked directly with the forestry sector on more practical and operational issues related to forest diseases during early stand establishment of plantation forests. Much of my research involved root diseases of Armillaria ostoyae and Phellinus sulphuascens; their distribution and impact on second growth forests, effectiveness of stump removal operations, and the effect of pre-commercial thinning on disease incidence with the overall aim of improving best management practices for dealing with root disease. I have also worked on projects involving the plethora of pathogens affecting lodgepole pine (Pinus contorta), the choice species for reforestation in BC, including Dothistroma septosporum, Cronatrium coleosporoides, Cronartium comandrae, Atropellis piniphila, Arceuthobium americanum and Endocronartium harknessii, as well as assessing performance of selected white pine against the rust pathogen Cronartium ribicola.
In 2007, I complete my PhD thesis at the University of British Columbia in Vancouver, British Columbia, Canada. My thesis was titled “Host responses of Douglas-fir, western hemlock and western redcedar to infection by Armillaria ostoyae and Armillaria sinapina”, supervised by Duncan Morrison and Bart van der Kamp. Armillaria root disease is the most important pathology concern in British Columbia’s interior forests where it causes significant mortality in conifers and growth loss on trees that sustain non-lethal infection. An important aspect of disease management is knowledge of species susceptibility and resistance mechanisms operating in trees that are effective against the fungus. My research looked specifically at how Armillaria develops within different conifer species of varying susceptibility and the type and nature of defense mechanisms induced in response to invasion by the fungus in the bark and in the wood. The research revealed a complex of host-mediated defense mechanisms that resulted in a significantly higher frequency of resistance reactions in western redcedar (Thuja plicata) compared to other conifers. These results have important implications for reforestation practices on diseased sites where stump removal is not an option. My main interest stemming from this work is to better understand disease development within host tissues at the cellular level for different pathogen/host complexes.