Artikkelit jotka sisältää sanan 'volume growth'
Vegetation patterns in a cut-away peatland in relation to abiotic and biotic factors: a case study from the Sumava Mts., Czech Rebuplic.
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We studied the natural regeneration of a cut-over peat bog in the Sumava Mountains,
Czech Republic. The spontaneous revegetation by vascular plants has been limited by
extreme abiotic conditions left after peat mining. Only 1-2% of the total area was
recolonized by Sphagnum mosses. This was mainly because drainage channels are still
drying out the bog. Only plants tolerant to water stress such as Juncus effusus, Molinia
caerulea, Eriophorum angustifolium and E. vaginatum were able to establish there. A
key species colonizing bare surface is a clonal plant E. angustifolium. It forms circular
polycormons of densely aggregated ramets. As in other radially spreading phalanx plants,
the oldest (central) part of the system gradually dies, previously connected ramets become
separated, and ring polycormon becomes open to recolonization by other plant
species. We analyzed the relationships between species richness of the ring and their
size, percentage litter cover, distance to seed sources, and soil fertility. The number of
plant species was higher in the middle of the polycormons. The soil was more fertile in
the central area than in the surroundings. We conclude that the restoration of highly
disturbed habitats can be facilitated by clonal behavior of pioneer populations.
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Lanta,
Faculty of Bilogical Sciences, University of South bohemia, Branisovska 31, CZ-370 05 Ceske Budejovice, CzechRebuplic
Sähköposti:
ei.tietoa@nn.oo
- Doležal, Sähköposti: ei.tietoa@nn.oo
- Samata, Sähköposti: ei.tietoa@nn.oo
Jatkolannoitusten vaikutus männyn (Pinus sylvestris L.) tilavuuskasvuun ja neulasten ravinnepitoisuuksiin ojitetulla rämeellä.
English title: The effect of repeated fertilizations on volume growth and needle nutrient concentrations of Scots pine (Pinus sylvestris L.) on a drained pine mire.
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The nutritional status of Scots pine (Pinus sylvestris L.) stands growing on a nitrogen-rich,
drained pine mire in western Finland was studied after refertilization using needle
analysis and the response of stand volume growth. The main aim was to find out if K-refertilization
alone could maintain or increase the volume growth without causing a
nutrient imbalance between K and P. The initial fertilization was carried out in 1961 -
62 using PK fertilizer and refertilized in 1976 and 1989 with different combinations of
nitrogen (N), phosphorus (P), potassium (K) and boron (B). Needle samples were taken
and the tree stands were measured in 1996 and 2001. Peat samples were taken in 2002.
According to the needle analysis results, the concentration of P was above the deficiency
level in all the treatments in 1995 and 2000. There was a clear shortage of K in
the needles collected from the control treatment, but the concentration of K was still
adequate 12 years after the latest K refertilization. The volume growth of the stands
clearly responded to the 1976 refertilization with K alone, which was probably due to
the fact that trees had been suffering from K deficiency before the first refertilization
and 14-15 years thereafter. After the second refertilization, the combination of K and P
increased the annual volume growth more than refertilization with K alone. This indicates
that about 25 years after the initial fertilization, there was already some shortage
of P. The highest stand volume was associated with the combined K (1976) and PK
(1989) refertilization treatment. Refertilization with N did not increase stand volumes
during the study period.
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Rautjärvi,
The Finnish Forest Research Institute, Joensuu Research Centre, Box 68, FIN-80101 Joensuu
Sähköposti:
ei.tietoa@nn.oo
- Kaunisto, Sähköposti: ei.tietoa@nn.oo
- Tolonen, Sähköposti: ei.tietoa@nn.oo
Kunnostusojituksen vaikutus rämemänniköiden kehitykseen.
English title: Effects of maintaining ditch networks on the development of Scots pine stands.
Avainsanat:
forest drainage;
peatland;
ditch cleaning;
complementary ditching;
tree stand;
Pinus sylvestris L.;
volume growth
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This study aimed at finding out the effects of maintaining ditch systems by ditch cleaning and complementary ditching on volume growth of drained Scots pine (Pinus sylvestris L.) stands. Volume growth during the first ten post-treatment years was increased by 0.16 m3 ha-1 a-1 after ditch cleaning, 0.36 m3 ha-1 a-1 after complementary ditching, and 0.48 m3 ha-1 a-1 after the combined treatment. The average growth reactions during the second five-year period were considerably higher than during the first one. No drastic reductions in stand growth, however, occurred in the untreated plots during the post-treatment period of ten years.
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Lauhanen,
The Finnish Forest Research Institute, Kaironiementie 54, FIN-39700 Parkano, Finland
Sähköposti:
ei.tietoa@nn.oo
- Ahti, Sähköposti: ei.tietoa@nn.oo
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