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Investigations were conducted on the chemical composition and the content of heavy metals in Salix caprea trees derived from the Zielonka Primeval Forest near Poznań. The content of cellulose, lignin and pentosans was similar to that found in literature and the quantities of heavy metals determined in individual parts of trees were similar to those found in trees growing in unpolluted areas.
The paper presents the chemical composition and the heat of combustion of selected willow bushes. Experiments were carried out on one-year old shoots of the following willow species and their crosses: Salix americana, Salix viminalis, Salix americana x Salix viminalis, Salix viminalis x Salix caprea, Salix viminalis x Salix acutifolia as well as on shoots of Orm Valne - Swedish variety.
Chemical composition of selected exotic wood species derived from the area of Africa was investigated by determining the contents of: cellulose, lignin, holocellulose, pentosans and substances soluble in organic solvents, in 1% NaOH solution, in cold and hot water, as well as the contents of mineral substances. The performed investigations revealed that concentrations of the determined constituents in individual wood species varied despite similar site and climatic conditions.
Comparative studies of ipe (Tabebuia spp.) wood photodegradation cause by treatment with outdoor and indoor UV-A light irradiation. A study on photodegradation of ipe (Tabebuia spp.) wood by UV A light has been carried out. Two types of lamps were used in the tests, i.e. a UVA-340 lamp with a wavelength of 290 - 400 nm, emitting light resembling natural light, an a UVA-351 lamp with a wavelength of 300 - 400 nm, imitating light found indoors penetrating through window panes. Colour of the samples was measured using a Datacolour 600 spectrophotometer prior and after 1,5, 10, 25, 50 and 100-hour irradiation. Characterization of investigated material included determination of its chemical components. Despite the fact that ipe wood contains high concentrations of components playing an important role in the photodegradation process (e.g. 37.2% lignin) the detected changes are minor and do not exceed 1 point. The change in colour (∆E) for ipe wood surface was mainly caused by changes in the chromatic coordinate (b*) and the lightness coordinate (L*). Greater changes occurred under the influence of a UV-340 lamp emitting the type of light resembling that found outdoors.
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