Artikkelit jotka sisältää sanan 'colonization'
Kasvualustan kuivumisen vaikutukset rahkasaraturpeeseen istutettujen männyntaimien ensikehitykseen.
English title: High and dry: Consequences of drought exposure in Scots pine seedlings grown in authentic peat soil.
Original keywords:
männyntaimet;
Pinus sylvestris;
kuivuus;
rahkasaraturve;
fotosynteesin tehokkuus (Fv/ Fm);
mykorritsat;
polyamiinit;
juurten ja versojen kasvu
English keywords:
drought;
Fv/Fm;
mycorrhizal colonization;
Pinus sylvestris seedlings;
poly-amines;
root and shoot growth;
Sphagnum-Carex peat
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Should the frequency of drought increase in boreal forests due to climate change, seedlings planted in prepared peat mounds could become more susceptible to soil desiccation. The resistance of Scots pine (Pinus sylvestris L.) seedlings to drought will thus be a key factor in the regeneration success of pine-dominated, forestry-drained peatlands. In this study, we evaluated the physiological, metabolic, and morphological responses of year-old seedlings gradually exposed to extreme drought in highly decomposed Sphagnum-Carex peat blocks. Drought clearly suppressed root and shoot growth as well as fractional colonization of ectomycorrhizal fungi. Sustained declines in photochemical efficiency (Fv/Fm) of previous-year and current-year needles did not occur until the volumetric soil water content had dropped to 30% and 10%, respectively. Polyamine analysis revealed that new needles are preferred in protecting the different parts of the seedlings against drought stress. Despite growth losses, the maintenance of rather high photochemical efficiency in current-year needles under severe water stress would appear to indicate a potential for seedling recovery if water availability in the peat improved. Given the high tolerance exhibited by Scots pine seedlings, death by drought seems a lesser concern.
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Pearson,
Finnish Forest Research Institute, Parkano Research Unit, Kaironiementie 15, FI-39700 Parkano, Finland
Sähköposti:
ei.tietoa@nn.oo
- Saarinen, Sähköposti: ei.tietoa@nn.oo
- Heiskanen, Sähköposti: ei.tietoa@nn.oo
- Sarjala, Sähköposti: ei.tietoa@nn.oo
- Laine, Sähköposti: ei.tietoa@nn.oo
Lieropopulaatioiden pitkäaikainen muodostuminen suonpohjien nurmiviljelyksillä Irlannissa.
English title: Long-term establishment of earthworm populations in grassland on reclaimed industrial cutaway peatland in Ireland.
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Earthworm populations in reclaimed cutaway peatland soils in central Ireland were sampled 20-30 years after reclamation and establishment of grass-clover leys following industrial peat mining. Nine earthworm species in total were present, with 4-7 species per field in the six fields sampled. Population densities were 130-506 individuals m-2, and biomass ranged from 80 to 279 g m-2. Thus, under favourable conditions reclaimed cutaway peat soils can support earthworm populations comparable in density and biomass to those typical of the most fertile mineral soils. However, species richness tended to be lower than in comparable grasslands on mineral soils, and reclaimed peat appears to be unfavourable for larger deep-burrowing species such as Lumbricus friendi and Lumbricus terrestris.
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Curry,
UCD School of Biology and Environmental Science, University College Dublin, Belfield, Dublin 4, Ireland
Sähköposti:
ei.tietoa@nn.oo
- Schmidt, Sähköposti: ei.tietoa@nn.oo
Kasvillisuus ja C02-tase käytöstä vapautuneella turvetuotantoalueella Kihniön Aitonevalla.
English title: Vegetation and CO2 balance in an abandoned harvested peatland in Aitoneva, southern Finland.
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The vegetation and CO2 balance (difference between C02 fixation rate and respiration rate) in an abandoned harvested peatland in Aitoneva, Kihnio (62° 12'N, 23° 18'E) were studied during the summer of 1994. The daytime CO2 fluxes from sample plots representing different kinds of vegetation were measured using two different static chamber techniques. To investigate the compositional variation of vegetation and its relationship with CO2 balance, data on the vegetation of the sample plots was analysed by global non-metric multidimensional scaling (GNMDS). A total number of 20 plant species was observed on the sample plots. The dominant plant species was Eriophorum vaginatum L. The main variation in GNMDS were connected with colonization stage (total cover of vegetation). The C02 fixation rate varied between -56 and 1869 mg m-2 h-1 and the respiration rate varied between 34 and 1168 mg CO2 m-2 h-1. The CO2 fixation and respiration rate increased with increasing total vegetation cover. The highest respiration and the highest CO2 fixation rates were found in sample plots dominated by mature Eriophorum vaginatum tussocks. Those sample plots were the only ones having positive CO2 balance. Regression analysis indicated that the respiration rate depended on soil temperature. Variation in the water table had no influence on the respiration or the C02 fixation rate.
Key words: CO2 balance, Eriophorum vaginatum, GNMDS, harvested peatland, plant colonization
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Tuittila,
Department of Forest Ecology, P.O. Box 24, FIN-00014 University of Helsinki, Finland
Sähköposti:
ei.tietoa@nn.oo
- Komulainen, Sähköposti: ei.tietoa@nn.oo
Suot sodanjälkeisessä asutustoiminnassa.
English title: Peatlands in the postwar colonization.
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After the Second World War appreciable areas of land in Finland were cleared for cultivation to replace cultivated fields lost in the war, in order to reach self-sufficiency in food production and to satisfy the need for land. The clearance of unproductive fens in northern Finland enabled the preservation of an equivalent area of productive forest in the central and southern parts of the country. One hectare of forest saved in this way can be estimated to have produced 160 m3 of wood from 1949 to the present time.
The colonization of Salla district in northern Finland is discussed in detail. The area of cultivated land increased by a factor of 12.3 during 1945-1969. The clearance remained unfinished, however, so that only a few of the farms reached the planned size and settlement remained smaller than intended. Nevertheless, information to date does not give any indication of cattle being given up any more rapidly on the colonization farms than on the old farms.
The area of peatland as a part of the whole cultivation has decreased but peat is still an essential feature in the agriculture of Lapland. The abundant supply of humus throughout the land is largely due to the peat. The greenhouse effect could increase the value of the northern peatlands.
Keywords: Agriculture, colonization, peatland cultivation
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Valmari,
Mäkiranta 2-4B 9, SF-96400 Rovaniemi, Finland
Sähköposti:
ei.tietoa@nn.oo
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