Evaluation of deposition fluxes in two mountain Norway spruce stands with different densities using the extended Canopy Budget Model

Abstract

The field study in a mountain forest at Bílý Kříž provides a comparison of element fluxes for two adjacent forest spruce stands of the same age (29 years in 2005) but with different stem densities. During five years (2001–2005), bulk and throughfall precipitation was sampled and analysed. Total deposition, dry deposition and canopy exchange fluxes were evaluated on the basis of the Canopy Budget Model. Highly significant differences in base cations, dissolved organic carbon, SO<sub>4</sub><sup>2−</sup>, F<sup>−</sup>, and Cl<sup>−</sup> throughfall concentrations were found between the sparser and denser spruce stands.  Throughfall, dry deposition and canopy exchange fluxes were also influenced by stand density. Annual throughfall fluxes of inorganic nitrogen were within 11.9–17.8 kg N·ha<sup>–1</sup>·yr<sup>–1</sup> on the sparser plot and within 15.4–20.6 kg N·ha<sup>–1</sup>·yr<sup>–1</sup> on the denser plot; annual throughfall fluxes of sulphur were within 15.3–20.3 kg S·ha<sup>–1</sup>·yr<sup>–1</sup> on the sparser plot and within 20.7–27.7 kg S·ha<sup>–1</sup>·yr<sup>–1</sup>on the denser plot. The critical load for nitrogen (11.2 kg N·ha<sup>–1</sup>·yr<sup>–1</sup>) was exceeded on both plots in all evaluated years 2002–2005.  Total annual inorganic nitrogen deposition was higher by up to 37.5% (in 2002) on the denser plot than on the sparser one.