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Wyszukujesz frazę "Rozenbergar, D." wg kryterium: Autor


Wyświetlanie 1-2 z 2
Tytuł:
Comparison of four methods for estimating relative solar radiation in managed and old-growth silver fir-beech forest
Autorzy:
Rozenbergar, D.
Kolar, U.
Cater, M.
Diaci, J.
Powiązania:
https://bibliotekanauki.pl/articles/41259.pdf
Data publikacji:
2011
Wydawca:
Polska Akademia Nauk. Instytut Dendrologii PAN
Tematy:
solar radiation
old-growth silver fir forest
beech forest
forest
light condition
forestry
hemispheric photography
Opis:
Methods based on the principle of hemispherical canopy projection, including hemispherical photography (digital andfilm), sensors like LAI 2000 (zenith cutoff anle 74,1°) andstable horizontoscope, represent less accurate, yet significantly less expensive andtime-consuming techniques for radiation measurements comparedto long-term measurement with a network of photosynthetically active radiation (PAR) sensors. With measurements taken at a single point in time they can provide reliable estimates of relative diffuse andd irect solar radiation andcan also be usedto estimate the light climate in different times of the year. The four above mentioned methods for solar radiation estimation were applied at the same points in gaps and under adjacent canopies in unevenaged, mixed Dinaric fir-beech and pure beech montane forests. Locations covereda range of radiation andstandstructure conditions. Data analyses showedgoodreliability of all four methods over the whole range (2–80%) of radiation conditions. The most comparable results come from LAI 2000 andfilm hemispherical photography (all R > 0.90). Digital hemispherical photography is an accurate andreliable (R = 0.89) replacement for film hemispherical photography, but the higher values estimatedfor direct radiation should be taken into account. Compared to the other three methods, the stable horizontoscope gives less accurate results, especially under canopies with poorly defined gaps. Our study showed that all four methods tested are suitable for estimating the solar radiation climate in gaps and stands with heterogeneous vertical structures, andhave potential value as a tool in decision making when practicing silviculture.
Źródło:
Dendrobiology; 2011, 65
1641-1307
Pojawia się w:
Dendrobiology
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Gap regeneration in near-natural European beech forest stands in Central Bohemia - the role of heterogeneity and micro-habitat factors
Autorzy:
Bilek, L.
Remes, J.
Podrazsky, V.
Rozenbergar, D.
Diaci, J.
Zahradnik, D.
Powiązania:
https://bibliotekanauki.pl/articles/41443.pdf
Data publikacji:
2014
Wydawca:
Polska Akademia Nauk. Instytut Dendrologii PAN
Tematy:
gap regeneration
natural regeneration
Europe
beech forest
Fagus sylvatica
competition
stand
Central Bohemian region
heterogeneity
microhabitat factor
Opis:
Gap regeneration in a European beech (Fagus sylvatica L.) forest reserve was analyzed in relation to within-gap resource heterogeneity and ground vegetation competition. The study was carried out in two one-hectare permanent research plots (PRP) which included five smaller research plots (RP) encompassing two large gaps (500–700 m2), two small gaps (300–400 m2), and location under canopy. The coverage of woody regeneration, ground vegetation, dead wood, seedling density in eight height classes, characteristics of dominant trees of the beech regeneration, and the total thickness of holorganic horizons were measured. Soil moisture and light conditions were also assessed in selected sample plots. The relative direct and diffuse light was estimated by hemispherical photography. Small gaps showed both the highest cover of tree regeneration and the highest density of individuals per hectare. Slightly less regeneration was recorded in large gaps, while under closed canopy, regeneration densities were 5–10 times lower than in small gaps. Beech regeneration cover and the size (diameter and height) of dominant beech seedlings were positively related to relative diffuse light and negatively related to ground vegetation cover. The latter was positively related to diffuse light and soil moisture content. A pronounced statistically significant contrast in the cover and size of beech regeneration in relation to micro-site conditions (diffuse light, cover of graminoids) was only confirmed between sample plots located below canopy cover and those within gaps. Graminoids, in particular Calamagrostis epigejos L., occurred mainly in the large gap centre and along the southernmost edge of the large gap, increasing competition for resources here. The cumulative cover of ground vegetation and regeneration was relatively low (9–56%) compared with more mesic natural beech forests. The indicated negative influence of direct light at the northern gap edge suggests that extension of gaps on comparable sites in managed forest should not proceed in this direction.
Źródło:
Dendrobiology; 2014, 71
1641-1307
Pojawia się w:
Dendrobiology
Dostawca treści:
Biblioteka Nauki
Artykuł
    Wyświetlanie 1-2 z 2

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