sdu faculty of forestry journal special edition 2009 - Orman Fakültesi

SDÜ Faculty of Forestry Journal
affected, considerable losses will occur and ash may lose much of its importance in
silviculture.
Figure 5. Hypothetical disease cycle of ash dieback caused by Hymenoscyphus albidus/
Chalara fraxinea. See text for explanations
Although many aspects are still unknown, much progress has recently been
made to better understand ash dieback and, based on this knowledge, to
recommend measures for disease management. However, this new phenomenon
reminds us, how little can in most cases be done against emerging forest health
problems. As a consequence of ash dieback the silvicultural characteristics of ash
need to be re-appraised. While it used to be a ‘stable’ tree species that was little
affected by diseases, insect pests and abiotic damaging factors, it is presently
threatened by this new phenomenon. It is therefore recommended to plant common
ash less extensively as before and mix it with other site-adapted tree species. Plants
for planting should be carefully inspected for the occurrence of symptoms by
nursery managers, forest owners and foresters. Likewise, it should be avoided to
bring diseased seedlings into areas, where ash dieback has thus-far not been
recorded. Wherever it is possible, leaves shed in autumn and leaf rachises on the
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