Forest acidification effects

Sverdrup, H Warft inge, R, and Nihlgard, B. (1994). Assessment of soil acidification effects on forest growth in Sweden. Water Air Soil Pollut.. 78, 1-36. 

Plants may be affected by indirect modifications of the environment. Soil acidification, for example, can cause the leaching of nutrients, and the release of toxic aluminum. These effects may operate together to produce nutrient deficiencies or imbalances to plants. High soil concentrations of aluminum may prevent uptake and utilization of nutrients by plants.Increased availability of aluminum in soils has been implicated as a cause of forest declines in both Europe and the United States, possibly through the toxic effects on small feeder roots 14),... 

The need to determine accurately the phase-specific concentrations of these pollutants reflects several concerns Compared to gaseous materials, particle-phase materials may penetrate more deeply into the human respiratory tract particle-phase pollutants scatter light much more effectively than gaseous materials, and they thus have a greater contribution to visibility reduction gaseous nitric acid has a much higher deposition velocity than particulate nitrates and can be a substantial contributor to the acidification of lakes, streams, forests, and vegetation. 

Raastad, I. A., and J. Mulder. 1999. Dissolved organic matter (DOM) in acid forest soils at Gardsjon (Sweden) Natural variabilities and effects of increased input of nitrogen and of reversal of acidification. Water, Air and Soil Pollution 114 199-219. 

Giesler, R. et al., Reversing acidification in a forested catchment in southwestern Sweden Effects on soil solution chemistry, J. Environ. Qual., 25, 110, 1996. 

Danielsson, R. M. Visser, S. (1989). Effects of forest soil acidification on ectomycorrhizal and vesicular-arbuscular mycorrhizal development. New Phytologist, 112, 41-7. 

Gorham E., Janssens J. A., Wheeler G. A., and Glaser P. H. (1987) The natural and anthropogenic acidification of peatlands. In Effects of Atmospheric Pollutants on Forests, Wetlands, and Agricultural Ecosystems (eds. T. C. Hutchinson and K. M. Memma). Springer, Berlin, pp. 493-512. 

One of the best present examples of the description of a toxic effect without much awareness or proof of tlie causality of the possible agents is the so-called acid rain wliich results in some Northern European countries in the acidification of poorly buffered soil and lakes, and to a decreased productivity in forest wood and lake-fisb. This toxic effect has been attributed to the acidity and mobility of aluminium salts resulting from the input of large quantities of SO ions in systems previously out of l each of pollutants from the dense industrial zones... 

The effects of upland acidification of freshwaters can be dramatic. Between 1930 and 1975 the median pH of lakes in the Adirondack Mountains of northeastern USA decreased from 6.7 to 5.1, caused by progressively lower pH in rainwater (Fig. 5.7). The acidified lakewater killed fish and other animals by several mechanisms. The problem for fish is that the dissolved Al3+ in the acidic water precipitates as an insoluble Al(OH)3 gel on the less acidic gill tissues, preventing normal uptake of oxygen and suffocating the animal. Similar problems have occurred in Scandinavia and Scotland. In addition to problems in freshwaters, the loss of forests in high-altitude areas has been linked to acid leaching, which leads to impoverishment of soils coupled with direct loss of cations from plant leaves. 

Nutritional benefits may often be associated with pollutant inputs. Depending on the amount of atmospheric input involved, the pollutants can be harmful - as seen in the case of N saturation or S eutrophication of forests in Central Europe (Johnson and Lindberg 1992). One of the most important indirect effects of the pollution load of forests is that of accelerated soil acidification by acid rain (Reuss and Johnson 1986, Kreutzer etal. 1998). Acid deposition also affects nutrient cycling processes in forest ecosystems (Ulrich 1991, Matzner 1988, Kazda 1990). 

Scientists have developed computer models that depict the physical, chemical and biological processes within forest watersheds. Watershed acidification models can be used as research and management tools to investigate factors responsible for the historical acidification of soil and water as well as the ecosystem response to anticipated future changes in acidic deposition. In order to effectively predict the pH, ANC and aluminum concentrations in streams, all major chemicals must be accurately simulated (e.g., sulfate, nitrate, calcium, magnesium). The acidification model PnET-BGC was used for this assessment because it has been rigorously tested at Hubbard Brook and other sites in the northeastern United States, and it allows the user of the model to consider the ecosystem response to multiple chemicals simultaneously. Other frequently used acidification models include MAGIC (Cosby et al. 2001), and NuCM (Lui et al. 1992). 

Nellemann, C. and Thomsen, N.G. (2001). Long-term changes in forest growth potential effects of nitrogen deposition and acidification. Water, Air, and Soil Pollution, 128, 197-205. 

Shaun A. Watmough is Assistant Professor in the Environmental and Resource Studies Department at Trent University. He received his Ph.D. from Liverpool John Moores University in the UK and completed several years of post-doctoral work at Trent University in Canada. His research interests include the effects of pollutants on soils and forests, trace metal cycling in the environment, and acidification of ecosystems. 

Acid rain has resulted in the widespread acidification of lakes and forests around the world. The areas most sensitive to acid rain are those without limestone deposits, such as the Adirondack region of New York State. The effect of acid rain is species-specific many species cannot adapt to lowered pH environments. Most fish species, for example, cannot survive in water with pH levels below 5.0. A detailed survey of 1469 Adirondack lakes and ponds in the mid-1980s showed that 352 lakes or ponds had pH values of 5.0 or less. In 346 of the identified lakes and ponds, no fish were found (Jenkins 2005). 

Kreiser.A., N. L. Rose, A. Probst .-C. Massabuau, 1995. Relationship between lake-water acidification in the Vosges mountains and S02-NO emissions in western Europe. In Landmann, G. M. Bonneau (eds.) Forest Decline and Atmospheric Deposition Effects in the French Mountains. 

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