Treesearch

The objectives of this study were twofold: (1) to develop a gamma densitometry technique for measuring the relative wood density and radial growth of trees from 12 mm increment cores; and (2) to determine whether changes in the relative wood density and radial growth of "resistant" eastern white pine (Pinus strobus L.) occurred after initiation of operations of the Kingston and Bull Run steam plants in eastern Tennessee. The study area was surveyed by air to determine the distribution of white pine around the Kingston and Bull Run steam plants. It was found that white pine was distributed...

The effect of acidic precipitation on vegetation is the result of an interaction between the acid and the plant. The metabolism of plants is dependent on optimal pH-values, which are maintained by regulation. There are differences in the effectiveness of regulation under such exogenous influences as acidic precipitation. These differences can be related to the resistance of plants to acidic precipitation or to certain pathogenic fungi. Such differences were measured as buffering capacity of homogenized leaves during titration with acid. There are significant differences in buffering...

The U.S. Clean Air Act provides mechanisms by which the public welfare may be protected from "any known or anticipated adverse effects associated with the presence of (an) air pollutant in the ambient air." The history of the U.S. Environment Protection Agency's (EPA) efforts to establish and defend a secondary ambient air quality standard for sulfur oxides is reviewed. The role of acid rain in producing "welfare effects" is described. Emphasis is given to the fact that a wide range of effects not simply limited to forest vegetation must be considered when designing pollution control...

Wind-blown rain, rain splash, and films of free moisture play important roles in the epidemiology of many plant diseases. The effects of simulated rain acidified with sulfuric acid were studied on several host-parasite systems. Plants were exposed, in greenhouse or field, to simulated rain of pH 3.2 ? 0.1 or pH 6.0 ? 0.2. Simulated "rain" of pH 3.2 resulted in: 1) an 86% inhibition in telia production of Cronartium fusiforme on Quercus phellos; 2) a 66% inhibition of reproduction of Meloidogyne hapla on field-grown Phaseolus vulgaris; 3) a 10% decrease in the severity of Uromyces phaseoli...

Several leaf cuticular features such as stomatal frequency, stomatal size, trichome length, type, and frequency, and subsidiary cell complex respond to environmental pollution in different ways and hence can be used as indicators of environmental pollution in an area. Several modifications in cuticular features under polluted environments seem to indicate ecotypic or survival significance for the plant species under investigation.

PH values and buffering capacity were determined for bark samples of 5 deciduous trees (oak, alder, hornbeam, ash, linden), one shrub (hazel) and one coniferous tree (Scots pine) in the Cracow Industrial Region (Southern Poland) and for comparison in the Bialowieza Forest (North-Eastern Poland). The correlation was found between acidification of tree bark and air pollution by SO2 in these areas. All trees showed the least acidic reaction in the control area (Bialowieza Forest), more acidic in Niepolomice Forest and the most acidic in the centre of Cracow city. The buffering capacity of the...

The Allen S. King Generating Plant near Bayport, Minnesota delivers 420 tons of sulfur dioxide to the atmosphere daily from a 789 foot (240 m) stack. Dispersal from this height theoretically minimizes harmful effects of the gases on vegetation. Six years of post-operational pH tests on hardwoods, in the area, show fluctuations in, but no significant increase of the bark acidity. Recorded pH values around the power plant were not significantly different from values obtained in several other localities in Minnesota. None of the pH values in Minnesota were within the ranges shown to be...

Ecosystem analysis as part of the International Biological Program, has shown that a considerable amount of nutrient input comes from the air through the filter action of vegetation. As investigations were carried out in remote areas, it appeared highly desirable to explore the conditions in the Ruhr district, one of the major industrial areas of the world.

We investigated both the current status of nitrogen fixation in Western Washington forests, and the potential effects of acid rain on this vital process. Even the low concentrations of sulfur dioxide presently found in the Northwest are thought to have an adverse effect on nitrogen fixation by limiting the distribution of the epiphytic nitrogen-fixing lichen, Lobaria pulmonaria, which is found mainly in deciduous forests. A close relative, L. oregano, was found to be the major nitrogen fixer in old-growth coniferous forests. It fixes less nitrogen following exposure to sulfuric acid of pH...

The effect of artificial acid rain on nitrogen uptake by a fungus [Glomus mosseae (Nicol. & Gerd. ) Gerd. & Trappe] endomycorrhizal with roots of sweetgum tree seedlings (Liquidambar styraciflua L.) was investigated by applying 3 kinds of test solutions to the surfaces of soil profiles planted with five combinations of sweetgum seedlings and fungus. Soil profiles were taken from a deciduous forest and were reconstituted in plastic pipes. Test solutions applied in different months were 1) artificial throughfall, 2) high ionic strength solutions first of pH 5.9 and later of pH 3.0, and 3)...