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Abstract: Aluminum (Al) chemistry was studied in soils and waters of two catchments covered by spruce (Picea abies) monocultures in the Czech Republic that represent geochemical end-members of terrestrial and aquatic sensitivity to acidic deposition. The acid-sensitive Lysina catchment, underlain by granite, was compared to the acid-resistant Pluhův Bor catchment on serpentine. Organically-bound Al was the largest pool of reactive soil Al at both sites. Very high median total Al (Alt) concentrations (40μmolL−1) and inorganic monomeric Al (Ali) concentrations (27μmolL−1) were observed in acidic (pH 4.0) stream water at Lysina in the 1990s and these concentrations decreased to 32μmolL−1 (Alt) and 13μmolL−1 (Ali) in the 2000s. The potentially toxic Ali fraction decreased in response to long-term decreases in acidic deposition, but Ali remained the largest fraction. However, the organic monomeric (Alo) and particulate (Alp) fractions increased in the 2000s at Lysina. In contrast to Lysina, marked increases of Alt concentrations in circum-neutral waters at Pluhův Bor were observed in the 2000s in comparison with the 1990s. These increases were entirely due to the Alp fraction, which increased more than 3-fold in stream water and up to 8-fold in soil water in the A horizon. Increase of Alp coincided with dissolved organic carbon (DOC) increases. Acidification recovery may have increased the content of colloidal Al though the coagulation of monomeric Al. [Copyright &y& Elsevier]

Dissolved organic carbon and nitrogen (DOC and DON) produced in the forest floor are important for ecosystem functions such as microbial metabolism, pedogenesis and pollutant transport. Past work has shown that both DOC and DON production are related to litterfall and standing stocks of C and N in the forest floor. This study, conducted in spring, 2003, investigated variation in forest floor water extractable DOC (WEDOC) and DON (WEDON) and forest floor C and N as a function of lignin, cellulose and N contained in live canopy foliage across eight Picea abies [L.] Karst stands in northern Bohemia. Based on Near Infrared Spectroscopy (NIR) analysis of foliar materials, lignin:N and cellulose:N content of the youngest needles (those produced in 2002) were positively and significantly related to WEDOC ( R 2 = 0.82–0.97; P<0.01) and to forest floor C:N ratio ( R = 0.72–0.78; P<0.01). Foliar N was strongly and negatively related to WEDOC and C:N ratio ( R = −0.91 and 0.72; P<0.05) among our study sites. WEDON was positively correlated to foliar lignin:N ( R = 0.48; P<0.05; n=40). Forest floor C pools were not positively correlated with foliar lignin and cellulose and forest floor N pools were not positively correlated with foliar N. Instead, a significant negative correlation was found between forest floor N pools and foliar cellulose ( R=−0.41; P<0.05), and between forest floor C pools and foliar N ( R = −0.44; P<0.05). From a remote sensing standpoint, our results are important because canopy reflectance properties are primarily influenced by the most recent foliage, and it was the chemistry of the most recently produced needles that showed a stronger relationship with forest floor WEDOC and C:N ratio suggesting forest floor production of WEDOC can be calculated regionally with remote sensing. [ABSTRACT FROM AUTHOR]

Abstract: The effect of European beech (Fagus sylvatica) and Norway spruce (Picea abies) on acid deposition and soil water chemistry was studied at a site in the Ore Mts., Czech Republic, that has been subjected to decades of elevated acidic deposition. Dry deposition onto the spruce canopy significantly increased acid input to the soil in comparison to the beech canopy. As a result soil waters were more acidic; Al, , and concentrations were significantly higher; and Ca and K concentrations were lower in the spruce stand than in the beech stand. The concentrations of potentially toxic inorganic aluminium (Alin) were, on average, three times higher in the spruce stand than in the beech stand. Thus, Al played a major role in neutralizing acid inputs to mineral soils in the spruce stand. Despite the higher dissolved organic carbon (DOC) concentrations in spruce organic soil solutions, organic Al (Alorg) accounted for only 30% of total Al (Altot), whereas in beech organic soil solutions Alorg was 60% of Altot. Soil waters in the beech stand exhibited Alin concentrations close to solubility with jurbanite (Al(SO4)OH·5H2O). The more acidic soil waters in the spruce stand were oversaturated with respect to jurbanite. The Bc/Alin ratio (Bc=Ca+Mg+K) in O horizon leachate was 4.6 and 70 in spruce and beech stands, respectively. In beech mineral soil solutions, the Bc/Alin ratio declined significantly to about 2. In the spruce stand, mineral soil solutions had Bc/Alin values below the critical value of 1. The observed Bc/Alin value of 0.4 at 30cm depth in the spruce stand suggests significant stress for spruce rooting systems. A more favourable value of 31 was observed for the same depth in the beech stand. The efficiency of the spruce canopy in capturing acidic aerosols, particulates, and cloud water has resulted in the long-term degradation of underlying soils as a medium for sustainable forest growth. [Copyright &y& Elsevier]

Estimates streamwater and soil chemistry between 1851 and 2030 at the Lysina catchment, an acid-sensitive granitic catchment covered by planted Norway spruce monoculture in the western Czech Republic. Total deposition of sulfur to the catchment; Role of organic acids in streamwater buffering; Estimated increase in streamwater pH and soil base saturation.

The MAGIC model was applied to estimate soil and soil water (−90cm) chemistry between 1854 and 2094 at two experimental stands (Načetín, Ore Mountains), one covered by a Norway spruce monoculture and the other by a natural European beech forest. The primary aims were to evaluate the influence of tree species on long-term acidification and to predict future development under different forest management scenarios. Depletion of base cations from the soils, caused by high acidic deposition, resulted in low base saturations of 8.2% at the spruce stand and of 6.4% at the beech stand in 2003. The concentration of aluminum in soil water was 135μmoll−1 and pH 4.32 at the spruce stand, and 70μmoll−1 and pH 4.4 at the beech stand, respectively, in 2005. During the peak of acidification in the mid 1980s, modeled aluminum concentrations contributed 70% to neutralizing acidity at the spruce stand, and 55% at the beech stand. In addition, SO4 concentration was significantly higher at the spruce stand (525μequiv.l−1) compared to the beech stand (330μequiv.l−1) as a result of higher dry deposition onto the spruce canopy. The enhanced leaching of base cations was comparable at both stands (191μequiv.l−1 at the spruce stand and 215μequiv.l−1 at the beech stand). The higher deposition of base cations onto the spruce canopy was able to partially mitigate the effect of high leaching. The model results suggest that future recovery of soil water will be significantly better at the beech stand (higher pH, ANC, Bc/Al ratio and lower SO4 2− and Al concentrations). Interestingly, modeled soil base saturation for 2094 will be lower at the beech stand. Alternative scenarios such as clear-cutting and new re-forestation resulted in more favorable soil chemistry for the beech plantations compared to the spruce. The best regeneration of the soil environment is predicted for the scenario with an absence of forest. This suggests, that future soil recovery from acidification will be delayed by the removal of base cations through harvesting. [Copyright &y& Elsevier]

Norway spruce ( Picea abies (L.) Karst.) stands in certain areas of Central Europe have experienced substantial dieback since the 1970s. Understanding the reasons for this decline and reexamining the response of forests to acid deposition reduction remains challenging because of a lack of long and well-replicated tree-ring width chronologies. Here, spruce from a subalpine area heavily affected by acid deposition (from both sulfur and nitrogen compounds) is evaluated. Tree-ring width measurements from 98 trees between 1000 and 1350 m above sea level (a.s.l.) reflected significant May–July temperature signals. Since the 1970s, acid deposition has reduced the growth–climate relationship. Efficient pollution control together with a warmer but not drier climate most likely caused the increased growth of spruce stands in this region, the so-called “Black Triangle,” in the 1990s. [ABSTRACT FROM AUTHOR]

Abstract: During the 1990s the emissions of SO2 fell dramatically by about 90% in the Czech Republic; the measured throughfall deposition of sulphur to a spruce forest at Načetín in the Ore Mts. decreased from almost 50 kg ha−1 in 1994 to 15 kg ha−1 in 2005. The throughfall flux of Ca decreased from 17 kg ha−1 in 1994 to 9 kg ha−1 in 2005; no change was observed for Mg. The deposition of nitrogen ranged between 15 and 30 kg ha−1 with no statistically significant trend in the period 1994–2005. The desorption of previously stored sulphur and the decrease of Ca deposition are the main factors controlling the recovery of soil solution. The pH of the soil solution at a depth of 30 cm remains unchanged, and the Al concentration decreased from 320 μmol l−1 in 1997 to 140 μmol l−1 in 2005. The enhanced leaching of base cations relative to no acidified conditions has continued, although the Ca concentration decreased from 110 μeq l−1 in 1997 to 25 μeq l−1 in 2005 in the mineral soil solution at 30 cm depth. This dramatic change was not observed for Mg concentration in soil solution, because its deposition remained stable during the observed period. Similar patterns were observed in the deeper soil solution at 90 cm. The reduction in Ca availability resulted in lower uptake by tree assimilatory tissues, measured as concentration in needles. Since 2005, the leaching of nitrate observed in soil solution at 30 cm depth has disappeared. By 2003 a similar situation occurred at 90 cm. Higher incorporation into the trees after 1997 could be an important factor. With respect to the formerly high sulphur deposition and consequently released aluminium, which could have negatively influenced the biotic immobilization driven by microbes and fungi, the recovery may have positively impacted and therefore improved retention in the ecosystem during recent years. The delay in the successful retention of nitrogen in the ecosystem was probably caused by the high mineralization of organic matter after improvement of chemical parameters in the organic horizon (increase in pH and decrease in Al concentration). It seems that high mineralization of stored organic matter after decades of high acidic deposition could be an important factor affecting the high losses of nitrogen in spruce forest ecosystems. [Copyright &y& Elsevier]