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Chapter 12. Flux-Based Ozone Risk Assessment for Adult Beech and Spruce Forests
出版Elsevier Inc. Chapters, 2013-11-19
主題Nature / Plants / TreesScience / Environmental ScienceScience / Life Sciences / Botany
ISBN01280556429780128055649
URLhttp://books.google.com.hk/books?id=owF1DAAAQBAJ&hl=&source=gbs_api
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註釋Rising tropospheric ozone (O3) concentrations pose a critical threat to forest ecosystems. A stomatal flux-based risk evaluation methodology at leaf level was established recently in the context of the Convention on Long-Range Transboundary Air Pollution. This study demonstrates improvement and validation of the stomatal flux–effect approach for European beech and Norway spruce with results from the 8-year free-air O3 enrichment experiment at Kranzberg Forest (Germany). Based on the recommended O3/water vapour diffusivity ratio of 0.663, provisional corrected flux–effect functions for beech and spruce were deduced. Comparison of observed and modelled loss in annual growth under twice-ambient O3 exposure relative to whole-stem productivity under ambient O3 seems to confirm the Convention’s leaf-level stomatal flux approach and the associated response function for Norway spruce up to twice-ambient O3 exposure. For European beech, it must be emphasized that the Convention’s methodology may underestimate the risk for loss in whole-stem productivity.