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Natural regeneration of Norway spruce in mountain forests and at disturbed plots
Urbanová, Renáta ; Hadincová, Věroslava (advisor) ; Brůna, Josef (referee)
The natural regeneration of Picea abies in undisturbed mountain spruce forests as well as in disturbed areas formed by windstorms and overgrowth of bark beetles, especially spruce bark beetle (Ips typographus), takes place primarily through seed germination from a transitional soil seed bank. The quality of the soil seed bank depends on the amount of seeds available, which varies significantly throughout years, and on environment conditions. Interannual changes in the amount of seeds produced are caused by the irregular occurrence of seed years, which reflects weather changes in the context of ongoing climate change. Increased average air temperature and unevenly distributed rainfalls throughout the year have a positive effect on the spruce phenology, seed abundance and quality and results in increasing frequency of seed years. The large amount of seeds during seed years induces increased abundance of granivores for which the seeds are the source of nutrients and environment for their development. Seed predators of invertebrates and, small vertebrates groups and fungal pathogens significantly reduce the proportion of seeds needed for spruce natural regeneration. This bachelor thesis summarizes up to now knowledge explaining mechanisms and interactions associated with the soil seed bank of Picea...
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Natural regeneration of mountain spruce forests: 10 years after a bark-beetle outbreak
Jonášová, Magda
An extensive area of mountain spruce (Picea abies (L.) Karst.) forests in the Šumava National Park has been affected by a massive bark beetle (Ips typographus (L.)) outbreak since the middle of the 1990s. Parts of forests were left without interventions, while salvage logging was applied in other areas. The results indicated that a natural succession of mountain spruce forests after a bark beetle outbreak, if left without interventions, avoids a pioneer stage and direct recovery of the spruce forests is possible. Wind-dispersed pioneer species appeared temporarily in clear-cuts shortly after salvage logging, but their share in the whole regeneration was negligible after ten years. The height and age structure of spruce regeneration was reduced in clear-cuts. There was also a severe effect of salvage logging on ground layer vegetation compared to the bark-beetle outbreak itself.
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Stonožky smrkových lesů Moravskoslezských Beskyd, Česká republika
Wytwer, J. ; Tajovský, Karel
Centipede communities (Chilopoda) were studied in five spruce forests (.i.Picea abies./i.) in the Moravskoslezské Beskydy Mts., Northern Moravia, Czech Republic. Investigations were carried out from 1988 to 1993 and afterwards repeatedly in the years 1996-1997 in 5 to 134 year-old forest stands situated at the localities Bílý Kříž and Kněhyně. The stands differed in altitude, in air pollution and degree of tree defoliation. A total of 15 species of centipedes was found in all stands studied. The most abundant species occurring in all studied stands were .i.Lithobius mutabilis, L. forficatus, L. burzenlandicus burzenlandicus, Geophilus insculptus./i.. The centipedes .i.L. burzenlandicus burzenlandicus, G. insculptus./i. predominated mainly in the soil samples, .i.L. forficatus./i. was abundant in pitfall traps only. The mean densities of the whole centipede communities ranged from 9.0 to 194.6 ind.m-2 in 1988-1993, the highest densities were characteristic for the youngest spruce stand.
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