Ash dieback and Dutch elm disease: Current situation and prospects in Slovenia

Abstract

Ash dieback has been present in Slovenia since 2006, and Dutch elm disease since 1929. We have evaluated their current situation in Slovenia based on sanitary felling. Sanitary felling of ash has risen exponentially from 2009 to 2017. In 2017, 76,101 m³ of ash or 69% of total felling was due to ash dieback, which represents 2% of ash wood stock. Geographically more damaged forests (0.5–2.1% of wood stock) were in the eastern part of Slovenia. We suspect that the sanitary felling of ash will escalate and follow the exponential trend to some level, and wood stock of ash will drop by 20–40% in next 10 years. From 1995 to 2013, between 51 and 59% of elm was sanitary felled due to Dutch elm disease. Trend of sanitary felling was disturbed between 2014 and 2016 because of the catastrophic ice damage that happened in 2014. The most damaged areas are in the southern part of Slovenia, where 11–75% of elm wood stock per forest management unit was damaged due to Dutch elm disease. However, in the most cases, only up to 2% of elm wood stock was sanitarily felled. The prospect for elms is becoming better over the years as sanitary felling due to Dutch elm disease in slightly lower, and the total wood stock of elms has risen from 2007 to 2013 and remained on that level since then. Therefore, we believe that elms are slowly recovering from Dutch elm disease. However, other damaging factors threaten elms.