T = 0: No documented human toxicity. Alnus glutinosa bark contains tannins and has long-standing ethnomedicinal use (astringent, traditional applications) without recorded clinical intoxications. Not listed in Bruneton (2009) or Frohne & Pfänder (2005) as a toxic species. Pharmacological activity does not constitute toxicity per methodology.
A = 0: No documented veterinary toxicity in livestock or companion animals. No reports in toxicological veterinary references.
I = 0: Native species in Luxembourg. Native across most of Europe, western Asia, and northern Africa. Cannot be classified as invasive in its native range.
Pop Alert Level: High (10–50M) — justified but not species-isolated. Basis: semi-direct estimate based on population-level sensitization studies and documented Betulaceae cross-reactivity. Available evidence: Buchs, Switzerland — 10.9 % of unselected schoolchildren IgE-positive to rAln g 1 (Gassner et al. 2014; schoolchildren cohort, not general adult population); Belgian general population (n=2,320) — 13.2 % sensitized to a tree pollen mix including birch, hazel, and alder (Blomme et al.; not species-specific to Alnus glutinosa); birch homologous group sensitization 8–16 % in European general populations (Biedermann et al. 2019). Aln g 1 (PR-10, 17 kD) shows 79–83 % sequence identity with Bet v 1 — extensive cross-reactivity within the birch homologous group means species-isolated EU-wide prevalence for A. glutinosa alone cannot be extracted from these aggregate figures. The "High (10–50M)" tier is therefore assigned on the basis of mass sensitization within the Betulaceae/Fagales pool to which A. glutinosa substantially contributes — not as a directly measured species-isolated value.