title: Rapid recovery of stem increment in Norway spruce at reduced SO2 levels in the Harz Mountains, Germany.
abstract: Tree-ring width of Picea abies was studied along an altitudinal gradient in the Harz Mountains, Germany, in an area heavily affected by SO(2)-related forest decline in the second half of the 20th century. Spruce trees of exposed high-elevation forests had earlier been shown to have reduced radial growth at high atmospheric SO(2) levels. After the recent reduction of the SO(2) load due to clean air acts, we tested the hypothesis that stem growth recovered rapidly from the SO(2) impact. Our results from two formerly damaged high-elevation spruce stands support this hypothesis suggesting that the former SO(2)-related spruce decline was primarily due to foliar damage and not to soil acidification, as the deacidification of the (still acidic) soil would cause a slow growth response. Increasing temperatures and deposited N accumulated in the topsoil are likely additional growth-promoting factors of spruce at high elevations after the shortfall of SO(2) pollution.
authors.affiliation: Department of Plant Ecology, Albrecht von Haller Institute of Plant Sciences, University of Göttingen, Untere Karspüle 2, 37073 Göttingen, Germany. mhauck@gwdg.de
authors.forename: Markus
authors.initials: M
authors.lastname: Hauck
authors.forename: Jorma
authors.initials: J
authors.lastname: Zimmermann
authors.forename: Mascha
authors.initials: M
authors.lastname: Jacob
authors.forename: Choimaa
authors.initials: C
authors.lastname: Dulamsuren
authors.forename: Claudia
authors.initials: C
authors.lastname: Bade
authors.forename: Bernd
authors.initials: B
authors.lastname: Ahrends
authors.forename: Christoph
authors.initials: C
authors.lastname: Leuschner
mesh_terms: D000393:Air Pollutants / Q000032:analysis / Q000633:toxicity*; D000397:Air Pollution / Q000706:statistics & numerical data; D001272:Atmosphere / Q000737:chemistry; D004784:Environmental Monitoring; D005858:Germany; D028222:Picea / Q000187:drug effects / Q000254:growth & development*; D011891:Rain / Q000737:chemistry; D013458:Sulfur Dioxide / Q000032:analysis / Q000633:toxicity*
chemical_list: D000393:Air Pollutants; D013458:Sulfur Dioxide