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Wyszukujesz frazę "diameter structure" wg kryterium: Wszystkie pola


Wyświetlanie 1-3 z 3
Tytuł:
Modele struktury grubości w jednopiętrowych drzewostanach z udziałem jodły Abies alba Mill. i buka Fagus sylvatica L.
Models of diameter structure in single-storied stands with fir Abies alba Mill.and beech Fagus sylvatica L.
Autorzy:
Podlaski, R.
Pach, M.
Powiązania:
https://bibliotekanauki.pl/articles/989766.pdf
Data publikacji:
2015
Wydawca:
Polskie Towarzystwo Leśne
Tematy:
lesnictwo
drzewostany mieszane
drzewostany jednopietrowe
struktura grubosci
jodla pospolita
Abies alba
buk zwyczajny
Fagus sylvatica
piersnice drzew
rozklad piersnic
rozklad Weibulla
forest patches
structural heterogeneity
tree diameter distribution
weibull distribution
Opis:
The objectives of the study were (1) to determine the models of diameter at breast height (dbh) distributions in single−storied mixed stands with fir Abies alba Mill. and beech Fagus sylvatica L. as well as (2) to assess the usefulness of Weibull distribution to approximation of empirical dbh distributions for distinguished models. In the Carpathians (southern Poland) and in the Świętokrzyskie Mountains (central Poland) 36 sample plots ranging in size from 0.1 to 0.4 ha were established. To identify the dbh distribution models in single−storied stands with similar empirical dbh distributions, the hierarchical cluster analysis (HCA) with the Jaccard's measure and the Ward's minimum variance agglomeration method was used. To approximate dbh distributions, the Weibull distribution was employed. Single−storied mixed stands with fir and beech, with the mean age between 50 and 70 years at the dbh, were characterised by a large diversity of dbh distributions. Three groups of stands (I, II, III) differing, among others, in average dbh were determined (fig. 1). In these groups the average dbh ranged from 23.5 to 32.6 cm, from 18.9 to 25.1 cm, and from 13.7 cm to 19.6 cm, respectively. Within these groups, seven models of unimodal distributions were selected (figs. 2−4; tab.). The models are characterised by varying degrees of asymmetry with the highest number of trees from less than 30/ha to more than 300/ha which occurred mainly in the dbh classes between 9 and 33 cm (models AS1, SM1, AS2, AS3, AS4, AS5, SM2). The results of χ² test indicate the high flexibility and suitability of Weibull distribution for modelling of such types of dbh structures.
Źródło:
Sylwan; 2015, 159, 07; 586-592
0039-7660
Pojawia się w:
Sylwan
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Modele struktury grubości w dwu- i wielopiętrowych drzewostanach z udziałem jodły Abies alba Mill. i buka Fagus sylvatica L.
Models of diameter structure in two- and multi-storied stands with fir Abies alba Mill. and beech Fagus sylvatica L.
Autorzy:
Pach, M.
Podlaski, R.
Powiązania:
https://bibliotekanauki.pl/articles/989729.pdf
Data publikacji:
2015
Wydawca:
Polskie Towarzystwo Leśne
Tematy:
lesnictwo
drzewostany mieszane
struktura grubosci
drzewostany dwupietrowe
drzewostany wielopietrowe
jodla pospolita
Abies Alba
buk zwyczajny
Fagus sylvatica
rozklad piersnic
rozklad Weibulla
rozklad mieszany
tree diameter modelling
forest complex structure
weibull mixture model
Opis:
The objectives of the study were (1) to determine the models of diameter at breast height (dbh) distributions in two− and multi−storied mixed stands with fir Abies alba Mill. and beech Fagus sylvatica L. as well as (2) to assess the usefulness of single Weibull distribution and two−component mixture of Weibull distribution to approximation of empirical dbh distributions for distinguished models of dbh structures. In the Świętokrzyskie Mountains, 21 sample plots ranging in size from 0.2 to 0.4 ha were established. To identify the models of dbh distributions, in two− and multi−storied stands with similar empirical dbh distributions, the hierarchical cluster analysis (HCA) with the Jaccard's measure and the Ward's minimum variance agglomeration method were used. To approximate dbh distributions, the single Weibull distribution and the two−component mixture of Weibull distribution were employed. In two− and multi−storied mixed stands with fir and beech, with the mean age between 50 and 70 at the dbh, four models of dbh distributions were determined (fig. 1). Two of them were decreasing, strongly asymmetric (OS and OJ models; fig. 2) and the other two were increasing in the initial phase and decreasing in the final, having two maximums (DM1 and DM2 models; fig. 3). In the stands with the complex structure mixed distribution should be used to approximate empirical data. The analysis revealed high suitability and versatility of Weibull distribution both as single form and two−component mixture.
Źródło:
Sylwan; 2015, 159, 08; 632-638
0039-7660
Pojawia się w:
Sylwan
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Wpływ konkurencji na przyrost grubości drzew w wyżynnych lasach mieszanych o złożonej budowie
Effect of competition on the diameter growth of trees in mixed upland forests with complex structure
Autorzy:
Śmigielski, A.
Socha, J.
Maciejewski, Z.
Pach, M.
Powiązania:
https://bibliotekanauki.pl/articles/989022.pdf
Data publikacji:
2017
Wydawca:
Polskie Towarzystwo Leśne
Tematy:
lesnictwo
Roztoczanski Park Narodowy
drzewostany naturalne
drzewostany mieszane
drzewa lesne
grab
buk
jodla
przyrost drzew
przyrost grubosci
wskazniki konkurencyjnosci
competition indices
natural stands
roztocze national park
Opis:
The aim of this study was to assess the effect of competition on diameter growth of European beech (Fagus sylvatica L.), silver fir (Abies alba Mill.) and European hornbeam (Carpinus betulus L.) in forests with complex structure. For each tree we calculated set of 20 competition indexes in 4 variants for determining the scale of the competitors influence. The use of such a set of indices, allowed to describe accurately the competition between trees in the specific conditions for the particular tree species. Given species belong to the group of shade−tolerant trees. The species composition of the tree stands and their structure are the results of long−lasting natural processes, which is different than in the majority of Polish forests. The empirical material collected in the years 1993 and 2003 in four sample plots of 0.5 ha each located in natural stands of the Roztocze National Park in south−eastern Poland. The relationships between the competition and the growth were analysed using generalized additive models. This method allows to extend of the standard linear model, by taking into account non−linear function of each variable. One of the option of quantifying competition processes is the use of competition indices. The competition situation of an individual tree was described using distance−independ and distance−depend indices. Each of analysed species reacts differently on competition. Among the three analyzed species, the best competition index CI15 explained 48.3% of the variation diameter growth of European beech (tab. 2). The competition index CI3 explained only 26.1% of the variation diameter growth of European hornbeam (tab. 2). It turned out to be the worst result for the described species. The competition index CI14 explained 31.1% of the variation diameter growth of silver fir (tab. 2). Additional use of DBH in the models, increased values of the coefficient of determination, and extended the possibilities to use the developed models.
Źródło:
Sylwan; 2017, 161, 05; 365-378
0039-7660
Pojawia się w:
Sylwan
Dostawca treści:
Biblioteka Nauki
Artykuł
    Wyświetlanie 1-3 z 3

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