¶ Hymenoscyphus pseudoalbidus
¶ Essentaksterfte (Ash dieback)
Fungi
¶ Why this species, in the context of the Amsterdamse Bos
The pathogen reshaping the Bos. Causes ash dieback. Since 2012, more than 1,300 ash trees in the Bos have been felled to halt its spread. Note: in waarneming.nl this is recorded under its older synonym Hymenoscyphus pseudoalbidus (the asexual form), or aggregated under H. albidus s.l., incl. H. pseudoalbidus. The fungus is rarely observed directly — only its effect on ash is visible. Almost certainly the highest-impact organism in the Bos right now.
¶ Facts from the graph
| Total observations in the Bos | 1 |
| First recorded | 2025-09-20 |
| Last recorded | 2025-09-20 |
| Max rarity tier | 2 — uncommon |
¶ Top sub-locations within the Bos
- Amsterdamse Bos - Kleine Kinderbad — 1 observations
¶ Explore
- View this species on the Bos map → (all observations, plotted geographically)
- Species page on waarneming.nl
- Bos-filtered observation list on waarneming.nl
- One example observation
Data derived from 136,107 waarneming.nl observations at location 5013 (Amsterdamse Bos), scraped May 2026. Bos-context text: manually composed from the Bosplan 2020–2030, amsterdamsebos.nl, and the existing Het Onzichtbare Zichtbaar dossiers.