We aimed to evaluate the changes in grassland soils resulting from forest tree planting using two soil quality indices-a soil evaluation factor (SEF) and a soil quality index (SQI). We studied the impact of introducing forest trees (conifers, broadleaves or mixed) on natural meadows. We examined how the soil properties were affected by the tree species and their ages (25, 35 and 65 years old). Soil samples were collected from meadows and their adjacent forests, all situated within the boundaries of Krakow (Poland). Before the trees were planted, all areas were grassland, used for agricultural and recreational purposes. The soil samples taken from surface and subsurface horizons were analysed for pH, nutrients (C, N, P, K, Mg), humus compounds and dehydrogenase activity (DHA), and basic cations (Ca 2+ , Mg 2+ , K + , Na +). The introduction of trees on the grasslands lowered the pH and DHA activity, and impoverished the soils in nutrients. The impact on the soil properties of the tree species was more important than their age. The biggest negative changes were found in the soils covered by coniferous trees, in which the lowest values of SEF and SQI (respectively, 9 and 0.24) were recorded. The highest values of both soil quality indices (SEF-147, SQI-0.66) were observed in the meadow soils. The soils of a 35-year-old deciduous forest and a 65-year-old forest with deciduous and coniferous tree species had similar SEF and SQI values. The deciduous trees adapted better to the meadow soils than the conifers and, over time, an improvement in the soil properties occurred as a result of the accumulation of tree residues.
This paper addresses an empirical method of assessment of the height of a virtual point source. In order to achieve such assessment, three planes defining the location of a virtual point source in a space are created and formulas describing the geometry of observer's sight and plume orientation are used. Data for calculations are obtained on a basis of plume photographs. The final position of a virtual emission point is described by a set of its coordinates in the Cartesian coordinate system. Presented method may be applied as a means to verify and validate the existing formulas describing the rise of plume above the stack exit or as a tool enabling acquisition of information for the sake of creating new formulas of this type. The calculation of the location of a virtual point source ascribed to the point emission from the roof of the bank of coke oven is presented and illustrated with photographs which reveal position of plume, adequate planes, axes and characteristic objects.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.