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Wyszukujesz frazę "basal area" wg kryterium: Temat


Wyświetlanie 1-3 z 3
Tytuł:
Porównanie sposobów określania składu gatunkowego drzewostanów obrębu leśnego
Comparison of the methods of determining the tree species composition of stands in a forest district
Autorzy:
Bruchwald, A.
Miścicki, S.
Dmyterko, E.
Stereńczak, K.
Wysocka-Fijorek, E.
Powiązania:
https://bibliotekanauki.pl/articles/985705.pdf
Data publikacji:
2019
Wydawca:
Polskie Towarzystwo Leśne
Tematy:
lesnictwo
sklad gatunkowy
struktura gatunkowa
metody badan
analiza porownawcza
obreby lesne
basal area
cover
diversity
sample plot
survey
volume
Opis:
In Polish forest management planning, the species composition of stands in a forest district is established by adding up the volumes of tree species from individual forest stands. These volumes are calculated according to the estimated share of species cover and the estimated volume of the entire forest stand. The species structure of stands in a forest district, established on the basis of such a method, may be different than that obtained from sample plots. The aim of the study was to compare three ways of determining the tree species structure of stands in a forest district. In Method 1, the species composition was estimated on the basis of the volume of trees measured on sample plots as part of a periodic forest inventory based on stratified sampling. The same data were used in Method 2, but the share of species was calculated on the basis of the basal area. In Method 3, the species structure was estimated according to the volume of trees estimated in each forest stand based on the cover of a given species. The empirical material was collected in 53 forest districts. In method 1 and 2, data from an average of 740 sample plots within the forest district were used. In Method 3, data from the forest stand descriptions contained in the database of the State Forests Information System were used. For each forest district, species composition was calculated, including 6 tree species and 8 groups of tree species. For all forest districts, the average shares of individual species and groups of species differed, depending on the applied method (tab. 1). In case of methods 1 and 2, the biggest difference was found for pine – the most numerous species – but it was also big for less numerous ones: birch and oak (tab. 2). In case of methods 1 and 3, the biggest difference in share was also found for pine (tab. 3). The greater the species diversity of a forest district (determined according to Simpson’s index of diversity), the greater was the average difference in the estimated share of an individual species (figs. 1 and 2). The method of determining the species structure in a forest district used in forest management practice nowadays was considered insufficient. It was proposed to establish it in larger units (subclass, age class, forest district) only according to the volume of trees measured on the sample plots (without rounding and ‘switching’ of species), using the stratified sampling method.
Źródło:
Sylwan; 2019, 163, 05; 365-372
0039-7660
Pojawia się w:
Sylwan
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Dokładność określania pierśnicowego pola przekroju drzewostanów bukowych na podstawie powierzchni próbnych
The accuracy of estimates of basal area in beech stands using sample plots
Autorzy:
Ochał, W.
Powiązania:
https://bibliotekanauki.pl/articles/1016133.pdf
Data publikacji:
2007
Wydawca:
Polskie Towarzystwo Leśne
Tematy:
drzewostany bukowe
dendrometria
piersnicowe pole przekroju
dokladnosc pomiaru
lesnictwo
powierzchnie probne
sample plot
sampling
stand basal area
beech stand
poland
Opis:
The paper presents the results of the research on the accuracy of estimates of basal area in beech stands using sample plots. The accuracy of estimates of the analysed characteristic was evaluated on the basis of variation coefficient value of the sums of tree basal areas on sample plots. The coefficient value was empirically determined for sample plots of various size, as well as for the secondary populations differing in plot number. The research was conducted in three beech stands of age class III, IV and VI growing in the territory of the Krzeszowice Forest District.
Źródło:
Sylwan; 2007, 151, 11; 10-21
0039-7660
Pojawia się w:
Sylwan
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Wpływ zwiększania się wieku drzewostanu dwupiętrowego na zmienność sum powierzchni przekroju pierśnicowego i miąższości drzew na powierzchniach próbnych różnych wielkości
Effect of ageing on the variation of basal area and volume sums on sample plots varying in size in a two-storey stand
Autorzy:
Turski, M.
Andrzejewski, T.
Powiązania:
https://bibliotekanauki.pl/articles/1022959.pdf
Data publikacji:
2005
Wydawca:
Polskie Towarzystwo Leśne
Tematy:
suma powierzchni przekroju piersnicowego
dendrometria
suma miazszosci drzew
drzewostany dwupietrowe
wiek drzewostanu
lesnictwo
powierzchnie probne
zmiennosc
sample plot
basal area
volume
two−storey stand
pine
oak
Opis:
The paper provides an analysis of changes in coefficients of variation of basal area and merchantable volume sums on sample plots of various sizes 1, 2, 4, 10, 6, 25 and 50 ares in a two−storey stand (storey I – pine 195 years, storey II − oak 105 years) over the last decade. The authors established how many times the number of sample plots of a given size at a given age should be increased in relation to the last measurement to attain the same result accuracy. Moreover, the optimal size of small sample plots that can grant the most accurate results was calculated.
Źródło:
Sylwan; 2005, 149, 09; 15-23
0039-7660
Pojawia się w:
Sylwan
Dostawca treści:
Biblioteka Nauki
Artykuł
    Wyświetlanie 1-3 z 3

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