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Excavation and treatment of sediments
Pokorný, J.
Methods aimed at reduction of internal nutrient loading in eutrophic water bodies are explained. Development of blue greens results both from external and internal loading. Eutrophic sediment in which anaerobic processes také place releases phospohorus which results in uncontrolled development of water blooms. Examples of hypertrophic lakes in which restoration was realised with success are given. Principles of sediment treatment aimed at immobilisation of phosphorus are explained. Aeration, P precipitation, nitrate application are described. Techniques for removal of eutrophic sediment both by classical and suction dreges are described. Relevant scientific literature is given.
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Productivity of differently managed mountain meadows
Mašková, Z. ; Květ, Jan ; Zelený, D.
A mountain meadow (about 1160 asl) situated in the Šumava NP/BR was subjected to 3 treatments applied in mid-July in 4 succesive years: (i)mowing, (ii)mulching, (iii)no management. Seasonal courses of aboveground biomass varied between 0,35-0,5 kg.m-2 in all treatments and years while belowground biomass did between 6-9 kg.m-2. R/S ratio varied between 6-18, being mostly highest in the mown treatment. Litter dry weight varied mostly between 0,2-0,8 kg.m-2, being usually hightest in the unmanaged treatment. Seasonal courses of the above 3 production characteristics were highly variable. Estimated average annual aboveground net production was 0,6-0,7 kg.m-2 for all treatments and years.
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Mycorhiza and its significance for forest trees
Chmelíková, Ewa ; Cudlín, Pavel
The article introduces the problematic of the mycorrhizal symbioses and presents the most wide spread and significant mycorrhiza types for forest trees. It discusses the practical use of mycorrhizal symbioses in forestry and the possibillity to influence the mycorrhizal status during tree sampling production, including various inoculation methods.
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Central-European mountain spruce forests: regeneration of tree species after a bark beetle outbreak
Jonášová, Magda
Two different approaches were applied to mountain spruce (Picea abies) forests attacked by bark beetle in the Šumava National Park (Czech Republic): (1) a small portion of the stands was left without intervention, relying upon natural regeneration, and (2) traditional technical measures were adopted, in which attacked trees were felled and removed. The results confirmed that the original tree species of the mountain spruce forests regenerate well under dead canopy and the bark beetle outbreak could even be considered as a tool for the restoration of their natural character.
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