Epidemiological derivation of flux-based critical levels for visible ozone injury in European forests

• Published in: Journal of forestry research Vol. 31; no. 5; pp. 1509 - 1519
• Main Authors: Sicard, Pierre, De Marco, Alessandra, Carrari, Elisa, Dalstein-Richier, Laurence, Hoshika, Yasutomo, Badea, Ovidiu, Pitar, Diana, Fares, Silvano, Conte, Adriano, Popa, Ionel, Paoletti, Elena
• Format: Journal Article
• Language: English
• Published: Berlin/Heidelberg Springer Berlin Heidelberg 01.10.2020; Springer; Springer Nature B.V; ARGANS, 260 route du Pin Montard, 06410 Biot, France%ENEA, Via Anguillarese 301, 00123 Santa Maria di Galeria,Italy%IRET-CNR, Via Madonna del Piano 10,50019 Sesto Fiorentino, Italy%GIEFS, 69 avenue des Hespérides, 06300 Nice, France%INCDS, 128 Eroilor Bvd., 077030 Voluntari, Romania%CREA, Viale S.Margherita 80, 52100 Arezzo, Italy
• Subjects: Air pollution; Biomedical and Life Sciences; Coniferous trees; Conifers; data collection; Defoliation; Detoxification; Dominant species; Epidemiology; Fluctuations; Fluxes; Forest protection; Forestry; forests; France; Injuries; Italy; Leaf area; Life Sciences; Moisture content; Monitoring; Original Paper; Ozone; Parameter estimation; Plant species; Romania; Soil moisture; Soil water; soil water content; Soils; Stomata; trees; Water content; France; Italy; Romania; Ozone; POD; Visible injury; Epidemiology; Critical levels
• ISSN: 1007-662X; 1993-0607
• DOI: 10.1007/s11676-020-01191-x

The European MOTTLES project set-up a new-generation network for ozone (O 3 ) monitoring in 17 plots in France, Italy and Romania. These monitoring stations allowed: (1) estimating the accumulated exposure AOT40 and stomatal O 3 fluxes (PODY) with an hourly threshold of uptake (Y) to represent the detoxification capacity of trees (POD1, with Y = 1 nmol O 3  m −2  s −1  per leaf area); and (2) collecting data of forest-response indicators, i.e. crown defoliation and visible foliar O 3 -like injury over the time period 2017–2019. The soil water content was the most important parameter affecting crown defoliation and was a key factor affecting the severity of visible foliar O 3 -like injury on the dominant tree species in a plot. The soil water content is thus an essential parameter in the PODY estimation, particularly for water-limited environments. An assessment based on stomatal flux-based standard and on real plant symptoms is more appropriated than the exposure-based method for protecting vegetation. From flux-effect relationships, we derived flux-based critical levels (CLef) for forest protection against visible foliar O 3 -like injury. We recommend CLef of 5 and 12 mmol m −2 POD1 for broadleaved species and conifers, respectively. Before using PODY as legislative standard in Europe, we recommend using the CLec for ≥ 25% of crown defoliation in a plot: 17,000 and 19,000 nmol mol −1 h AOT40 for conifers and broadleaved species, respectively.