| Municipality Alphen aan den Rijn |
Illustrated report mysterious damage to tree trunks, no biological factor found! For all documents of the municipality of Alphen aan den Rijn, concerning the Tree-Investigations Illustrated rapport Tree damage of unknown origin , December 2009. There is an urgent need for further research on the topic of damage to tree trunks. About 35 % of all broadleaf trees in the public spaces is affected. No biological factor was found! |
| Wageningen University (celbiology) | Formation of vascular inclusions in phloem of a.o. Fraxinus and Gleditsia |
| Arborist News | In the recent years it was observed that Fraxinus excelsior in the city of Alphen aan den Rijn in the Netherlands formed a kind of node-like protuberancestheir trunks. Up to 30% of the ash-trees are affected in the urban environment. September 2007. |