title: Are Bavarian forests (southern Germany) at risk from ground-level ozone? Assessment using exposure and flux based ozone indices.
abstract: Exposure and flux-based indices of O3 risk were compared, at 19 forest locations across Bavaria in southern Germany from 2002 to 2005; leaf symptoms on mature beech trees found at these locations were also examined for O3 injury. O3 flux modelling was performed using continuously recorded O3 concentrations in combination with meteorological and soil moisture data collected from Level II forest sites. O3 measurements at nearby rural open-field sites proved appropriate as surrogates in cases where O3 data were lacking at forest sites (with altitude-dependent average differences of about 10% between O3 concentrations). Operational thresholds of biomass loss for both O3 indices were exceeded at the majority of the forest locations, suggesting similar risk under long-term average climate conditions. However, exposure-based indices estimated higher O3 risk during dry years as compared to the flux-based approach. In comparison, minor O3-like leaf injury symptoms were detected only at a few of the forest sites investigated. Relationships between flux-based risk thresholds and tree response need to be established for mature forest stands for validation of predicted growth reductions under the prevailing O3 regimes.
authors.affiliation: WIDI, Wissenschaftsdienste, Ecological Science Services, Ortsstrasse 23, D-85354 Freising, Germany. manuela.baumgarten@alice-dsl.net
authors.forename: Manuela
authors.initials: M
authors.lastname: Baumgarten
authors.forename: Christian
authors.initials: C
authors.lastname: Huber
authors.forename: Patrick
authors.initials: P
authors.lastname: Büker
authors.forename: Lisa
authors.initials: L
authors.lastname: Emberson
authors.forename: Hans-Peter
authors.initials: HP
authors.lastname: Dietrich
authors.forename: Angela J
authors.initials: AJ
authors.lastname: Nunn
authors.forename: Christian
authors.initials: C
authors.lastname: Heerdt
authors.forename: Burkhard
authors.initials: B
authors.lastname: Beudert
authors.forename: Rainer
authors.initials: R
authors.lastname: Matyssek
mesh_terms: D000393:Air Pollutants / Q000032:analysis / Q000633:toxicity*; D004781:Environmental Exposure; D004784:Environmental Monitoring / Q000379:methods; D029964:Fagus / Q000187:drug effects / Q000254:growth & development*; D005858:Germany; D010126:Ozone / Q000032:analysis / Q000633:toxicity*; D018515:Plant Leaves / Q000737:chemistry* / Q000187:drug effects; D018570:Risk Assessment / Q000379:methods
chemical_list: D000393:Air Pollutants; D010126:Ozone