Comparison of deposition fluxes on the open area and in mountain spruce stands of different density

Abstract

ABSTRACT:To better understand the chemical transformation of rainfall after the passage through the canopies it is necessary to study throughfall deposition fluxes within forest stands. The comparison of bulk deposition fluxes of Ca, Mg, K, S-SO 4 , N-NO 3 and N-NH 4 in mountain spruce stands of different stand density and bulk deposition fluxes on the open area was made at the study site Bílý Kříž (Moravian-Silesian Beskids Mts., Czech Republic) during the period of 1999-2006. A linear relationship between the amount of rainfall on the open area and the amount of throughfall in the spruce stand was found. Throughfall deposition fluxes of selected elements in the dense as well as in the sparse spruce stands were higher when compared with bulk deposition fluxes on the open area. There were mostly statistical significant differences between the bulk deposition fluxes on the open area and those in the studied spruce stands. The throughfall deposition fluxes of Ca, Mg, K and S-SO 4 were influenced by the spruce stand density. (e.g. "Convention on Long-range Transboundary Air Pollution", "International Cooperative Programme on Integrated Monitoring of Air Pollution Effects on Ecosystems"). In the Czech Republic the forests in the border mountains and the forests at the highlands might be still endangered by the consequence of former soil acidification in spite of the fact that the concentrations of acidifying substances in the air have substantially decreased. In this paper deposition fluxes of selected elements in mountain spruce stands of different stand density and deposition fluxes on the open area are evaluated at the study site Bílý Kříž (Moravian-Silesian Beskids Mts., Czech Republic) for the period of 1999-2006. METHODThe study site is located at Bílý Kříž in the Moravian-Silesian Beskids Mts. (Czech Republic). Geographic coordinates, climatic and soil parameters of the site are given in Table 1. Bulk deposition fluxes on the open area and throughfall deposition fluxes of Ca, Mg, K, S-SO 4 , N-NO 3 and N-NH 4 in the mountain spruce stands of different stand density were evaluated during the period of 1999-2006. Spruce stand was planted in 1981 using four-yearsold seedlings of Picea abies (L.) Karst., hence the trees age was 30 years in 2007. The mean slope of the plot with the spruce stand is 13.5°, its exposure is SSE and mean altitude 908 m a.s.l. Dolomitic limestone (31% CaO, 21% MgO) was used for the aerial liming of the spruce stand in 1983, 1985 and 1987 (3 t/ha was applied every year, respectively). The studied spruce stand is divided into two plots with different stand density (FD -dense stand, FS -sparse stand). Leaf area index and stand density of the spruce stand on the studied plots are shown in Table 2.For throughfall sampling in the spruce stands and atmospheric precipitation sampling on the open area, permanently open polyethylene sampling vessels of an area of 335.33 cm 2 were used (Block, Bartels 1985;Niehus, Bruggemann 1995). The vessels were inserted into the thick-walled plastic pipes...