associated fungi, their pathogenicity and implications for silviculture
Dieback of Fraxinus excelsior in the Baltic Sea Region.
Acta Universitatis agriculturae Sueciae, 1652-6880
This thesis is comprised of three main studies: (1) the wood-inhabiting fungi found in declining European ash (Fraxinus excelsior L.) and their pathogenicity; (2) the relationship between F. excelsior phenology, site density and the susceptibility to the dieback; and (3) the potential of natural regeneration of dieback affected ash stands. The studies that are presented here were conducted in Denmark, Lithuania and Sweden.
Combination of different sampling and detection methods revealed a high diversity of fungi in both healthy looking and symptomatic tissues of declining F. excelsior. The most frequently detected fungal taxa were Alternaria alternata, Armillaria cepistipes, Aureobasidium pullulans, Botryosphaeria stevensii, Cladosporium cladosporioides, Cryptococcus foliicola, Epicoccum nigrum, Gibberella avenacea, Hymenoscyphus pseudoalbidus, Lewia sp., Phoma spp. and Phomopsis sp.
In pathogenicity tests nine fungal taxa caused symptomatic discoloration of bark and cambium on F. excelsior saplings, though only H. pseudoalbidus infected substantial proportion (50-100%) of tested trees.
The seasonal pattern of ash dieback severity, attributed to crown damage of F. excelsior trees, significantly increased towards the end of the investigated growth season. Severity of dieback symptoms was more pronounced in the unthinned stands, but otherwise was not related with stand density. However, susceptibility of F. excelsior to the disease was found to be dependent on the flushing (bud-bursting) phenology of the trees - late-flushing F. excelsior were most severely affected.
Our study demonstrated that vigorous natural regeneration of F. excelsior in examined clear-felled sites cannot be expected. Regenerating F. excelsior exhibited abundant dieback symptoms. The species composition in sites with long disease history is likely to shift away from F. excelsior to early successional pioneer species such as Alnus incana, Betula spp., and in some instances Populus tremula.
|Title:||Dieback of Fraxinus excelsior in the Baltic Sea Region|
|Subtitle:||associated fungi, their pathogenicity and implications for silviculture|
|Series/Journal:||Acta Universitatis agriculturae Sueciae (1652-6880)|
|Year of publishing :||23 January 2013|
|Number of Pages:||48|
|Place of Publication:||Uppsala|
|Publisher:||Dept. of Forest Mycology and Plant Pathology, Swedish University of Agricultural Sciences|
|ISBN for printed version:||978-91-576-7767-9|
|Publication Type:||Doctoral thesis|
|Full Text Status:||Public|
|Agris subject categories.:||H Protection of plants and stored products > H20 Plant diseases|
K Forestry > K10 Forestry production
|Subjects:||(A) Swedish standard research categories 2011 > 4 Agricultural Sciences > 401 Agricultural, Forestry and Fisheries > Forest Science|
|Agrovoc terms:||fraxinus excelsior, forest trees, dieback, forest decline, chalara, armillaria, pathogenicity, root rots, natural succession, lithuania, denmark, sweden|
|Keywords:||Armillaria spp., Hymenoscyphus pseudoalbidus, Fraxinus excelsior, pathogenicity, regeneration, succession, wood-inhabiting fungi|
|Department:||(NL, NJ) > Dept. of Forest Mycology and Plant Pathology|
(S) > Dept. of Forest Mycology and Plant Pathology
|External funders:||Nordic Council of Ministers|
|Deposited By:||Remigijus Bakys|
|Deposited On:||23 Jan 2013 06:17|
|Metadata Last Modified:||02 Dec 2014 10:54|
Repository Staff Only: item control page