As part of the Lebendige Luppe project, ash dieback disease was recorded on European ash trees (Fraxinus excelsior, trunks >5cm breast height diameter) on 60 plots (each 2500m²) in the late summers of 2016 to 2024. The trees were assessed according to Langer et al. (2015). However, an additional category 6 (dead tree) was introduced to distinguish between dead and dying trees. The selection of trees (according to their size) was based on 2 forest inventories (2016 and 2020) (Rieland et al. 2024, Scholz et al. 2022). As a result, new trees were added for recording in 2021.From 2020, the additional parameter Tree damage class, ash bark beetle was introduced to assess the damage caused by the ash bark beetle in 4 categories. From 2023, an additional parameter Tree damage class, ash dieback crown was introduced, which based on Lenz et al. (2012) and indicates the damage in the crown of the tree. This classification was added because, unlike the Langer et al. (2015) classification, it describes the damage class independently of the beetle infestation. A comparison of the different damage classifications enables a better description of the damage pattern. A more detailed description of the three parameters used (Tree damage class, ash dieback; Tree damage class, ash bark beetle and Tree damage class, ash dieback crown) is provided in the dataset comment.

Tree damage class, ash dieback:0 - no beetle infestation, full foliage, vital ash, without symptoms ofash dieback disease in the crown area;1 = crown with reduced foliage, no beetle infestation on the trunk, notypical shoot damage visible;2 = no infestation by bark-breeding beetles, crown with sparse foliage;3 = numerous dead branches and typical ash dieback disease symptoms inthe crown area: browned young shoot tips, isolated attempts to drillholes by bark brooders, beginning establishment of secondary pathogens(e.g. rhizomorphs [strands of hyphae] of honey fungus or velvety rootrot visible on emerging roots);4 = stronger leafy branches partly already dry on one side, onlyresidual crown left, beginning infestation by bark-breeding beetles(e.g. small colourful and large black ash bark beetle), Visibleinfestation with wood-degrading weakness parasites (e.g. honey fungus);5 = crown without foliage; in the trunk area partly still isolatedemergency shoots, heavy infestation with bark-breeding beetles in thecrown, but also starting at the trunk, wood rot (white, brown or mouldrot) at the base of the trunk and in the root area;6 = dead treeTree damage class, ash bark beetle (Damage class induced by ash bark beetle (Hylesinus oleiperda, Leperisinus varius, Hylesinus crenatus):0 = no evidence of bugs1 = few small entrance holes2 = many entrance holes but no other symptoms are visible like bark losses3 = many large and small entrance holes, bark losses, tree is heavily damaged by beetle infestationTree damage class, ash dieback crown (Damage class of the tree crown):0 = healthy crown, 0-10% defoliation1 = Dead shoot tips on the outer crown, 11-30% defoliation2 = Branching structures visible on the dead shoot tips,transparency of the crown possible, 31-50% defoliation3 = Formation of secondary crown, single strong branches broken off, 51-80% defoliation4 = only residual crown visible, defoliation 81-99%5 = dead tree, 100% defoliationTree, status:Describes whether the tree is living (tree) or dead (dw). Where possible, dw was described more finely than lying deadwood (ldw) or standing deadwood (sdw).