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Wyszukujesz frazę "mixed forests" wg kryterium: Temat


Wyświetlanie 1-4 z 4
Tytuł:
Regeneration-degeneration processes in the inland dune forests in protected areas of central Poland (Kampinos National Park)
Autorzy:
Kowalska, Anna
Kołaczkowska, Ewa
Powiązania:
https://bibliotekanauki.pl/articles/1035996.pdf
Data publikacji:
2015
Wydawca:
Uniwersytet Warszawski. Wydział Geografii i Studiów Regionalnych
Tematy:
Pine forests
mixed oak-pine forests
regeneration
inland dunes
Kampinos National Park
central Poland
Opis:
The aim of our study was to quantify the differences in the regeneration-degeneration processes in pine and mixed oak-pine forest habitats in the Kampinos Forest (central Poland). We investigated whether the regeneration rate depends on habitat type, whether there is a relationship between the bilberry (Vaccinium myrtillus) cover and the degree of community deformation, and which habitat type has been most invaded by alien plant species. Our results indicate that the constant loss of pine forest habitats, which has been observed since the 1970s, is continuing. The less deformed communities generally have more bilberry coverage, the stands in pine forest habitats are older and less deformed, and the stands in mixed oak-pine forest habitats are more susceptible to the spread of alien species, but are able to regenerate faster after a disturbance. These results are in line with observations from other parts of Poland and other European countries.
Źródło:
Miscellanea Geographica. Regional Studies on Development; 2015, 19, 4; 56-63
0867-6046
2084-6118
Pojawia się w:
Miscellanea Geographica. Regional Studies on Development
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Struktura, dynamika i właściwości opadu roślinnego w 110-letnim drzewostanie bukowym z domieszką sosny i świerka
Structure, dynamics and properties of litterfall in a 110-year-old beech stand with admixture of pine and spruce
Autorzy:
Jonczak, J.
Powiązania:
https://bibliotekanauki.pl/articles/973709.pdf
Data publikacji:
2011
Wydawca:
Polskie Towarzystwo Leśne
Tematy:
drzewostany bukowo-sosnowo-swierkowe
dynamika opadu
sklad frakcyjny
leśnictwo
właściwości chemiczne
opad roślinny
skład frakcyjny
drzewostany bukowo-sosnowo-świerkowe
litterfall
nutrient cycling
mixed forests
north-west Poland
Opis:
The aim of this study was to characterise the aboveground litterfall in a 110−year−old beech stand with admixture of pine and spruce based on a 3−year measurement series. The studies were conducted in 2007−2009 in the Leśny Dwór Forest District (NW Poland). The input of litterfall during the study period amounted from 3.234 to 4.871 t/ha/year. Beech, pine and spruce contributed in the total litterfall mass in 50.8−70.1%, 11.4−11.9% and 1.6−24.0% respectively. Beech leaves were the main component of litterfall, accounting for 39.6−52.4%. In the masting year for beech (2009), seed coats and beech seeds had also a significant share in the mass of litterfall. The bark beetle outbreak, which occurred during the study period, influenced the dynamics and properties of spruce needle fall. In the outbreak year (2008), a several fold increase in the mass of needle fall, mainly green needles, from spruce trees was observed. The beech leaf fall compared with other components of the stand was rich in phosphorus, potassium and calcium, and moderately rich in nitrogen, had the lowest C:N and C:P ratios and the highest pH value. The needle fall of pine and spruce was much less rich in nutrients and strongly acidic. It also showed a broad range of C:N and C:P values.
Źródło:
Sylwan; 2011, 155, 11; 760-768
0039-7660
Pojawia się w:
Sylwan
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Struktura naturalnego drzewostanu buczyny karpackiej w Tatrach na tle naturalnych buczyn z innych masywów Karpat
Structure of natural stand of a carpathian beech forest in the Tatra mountains compared with natural beech stands from other parts of the Carpathian
Autorzy:
Szwagrzyk, J.
Sułowski, W.
Skrzydłowski, T.
Powiązania:
https://bibliotekanauki.pl/articles/1018691.pdf
Data publikacji:
2006
Wydawca:
Polskie Towarzystwo Leśne
Tematy:
Tatry
Karpaty
lesnictwo
drzewostany naturalne
struktura drzewostanu
buczyna karpacka
canopy stratification
diameter distribution
height distribution
mixed temperate forests
natural stands
Opis:
The aim of this study was to compare the structure of newly found remnant of natural beech forest in Suchy Żleb in the Tatra mountains with the structure of natural tree stands in other parts of the Carpathians. In the sample plot of the size of 1 ha the stand basal area amounted to 36.7 m2; of that, 42.7% was beech, 37.4% silver fir, 19.8% Norway spruce, and 0.1% sycamore maple. In the units of volume silver fir was the most important tree in the stand (47%), while the share of beech was only 33%; the total wood volume of live trees was equal to 446.8 m3/ha. Tree number was equal to 442, among them 327 beeches, 73 silver firs and 41 Norway spruces. Number of snags was 26, and their volume 26.16 m3. Total amount of coarse woody debris was 159 m3 per hectare. Sub−canopy layer was dominated by beech, the middle layer of tree stand was a mixture of all three species, and the highest canopy layer consisted only of spruce and fir. The analyzed stand had biomass accumulation slightly below the average for the natural mixed beech forests of the Carpathians, probably because of selective tree cutting in the past. Because Suchy Żleb is the only remnant of natural stand in the montane zone of the Tatra mountains, it is very valuable as an object for comparisons with natural beech stands growing in other ranges of the Carpathians.
Źródło:
Sylwan; 2006, 150, 09; 3-15
0039-7660
Pojawia się w:
Sylwan
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
APPLICATION OF MIXED MODELS AND FAMILIES OF CLASSIFIERS TO ESTIMATION OF FINANCIAL RISK PARAMETERS
Autorzy:
Grzybowska, Urszula
Karwański, Marek
Powiązania:
https://bibliotekanauki.pl/articles/452746.pdf
Data publikacji:
2015
Wydawca:
Szkoła Główna Gospodarstwa Wiejskiego w Warszawie. Katedra Ekonometrii i Statystyki
Tematy:
LGD
mixed models
random forests
gradient boosting
Opis:
The essential role in credit risk modeling is Loss Given Default (LGD) estimation. LGD is treated as a random variable with bimodal distribution. For LGD estimation advanced statistical models such as beta regression can be applied. Unfortunately, the parametric methods require amendments of the “inflation” type that lead to mixed modeling approach. Contrary to classical statistical methods based on probability distribution, the families of classifiers such as gradient boosting or random forests operate with information and allow for more flexible model adjustment. The problem encountered is comparison of obtained results. The aim of the paper is to present and compare results of LGD modeling using statistical methods and data mining approach. Calculations were done on real life data sourced from one of Polish large banks.
Źródło:
Metody Ilościowe w Badaniach Ekonomicznych; 2015, 16, 1; 108-115
2082-792X
Pojawia się w:
Metody Ilościowe w Badaniach Ekonomicznych
Dostawca treści:
Biblioteka Nauki
Artykuł
    Wyświetlanie 1-4 z 4

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