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Wyszukujesz frazę "Ochal, W." wg kryterium: Autor

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    Wyświetlanie 1-5 z 5
    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:
    Rozklad przyrostu grubosci na przekroju poprzecznym drzewa w gorskich drzewostanach swierkowych
    Autorzy:
    Ochal, W.
    Powiązania:
    https://bibliotekanauki.pl/articles/811506.pdf
    Data publikacji:
    1998
    Wydawca:
    Polskie Towarzystwo Leśne
    Tematy:
    dendrometria
    przekroj poprzeczny
    swierk
    Picea
    drzewostany swierkowe
    lasy gorskie
    przyrost grubosci
    lesnictwo
    rozklad przyrostu grubosci
    drzewa lesne
    Źródło:
    Sylwan; 1998, 142, 11; 69-86
    0039-7660
    Pojawia się w:
    Sylwan
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Szerokość pasma jądrowego estymatora rozkładu pierśnic w drzewostanach olszy czarnej (Alnus glutinosa (L.) Gaertn.) z zachodniej części Kotliny Sandomierskiej
    Bandwidth of kernel estimator of DBH distribution in black alder (Alnus glutinosa (L.) Gaertn.) stands from west part of the Sandomierz Basin
    Autorzy:
    Pogoda, P.
    Ochał, W.
    Orzeł, S.
    Powiązania:
    https://bibliotekanauki.pl/articles/985919.pdf
    Data publikacji:
    2018
    Wydawca:
    Polskie Towarzystwo Leśne
    Tematy:
    lesnictwo
    dendrometria
    drzewa lesne
    olsza czarna
    Alnus glutinosa
    piersnice drzew
    rozklad piersnic
    estymacja
    estymatory jadrowe nieparametryczne
    kernel estimator
    bandwidth
    dbh structure
    black alder
    Opis:
    Set of ‘nonparametric’ methods, that don’t make a priori assumption about functional form of empirical distribution was developed as an alternative to the parametric distribution modeling. The kernel estimators are one of such methods, that can be used to describe the frequency of data representing for example DBH records. Kernel smoothing requires the choice of weighting function and bandwidth also called as smoothing parameter or window. The lack of comprehensive analysis on the applicability of particular bandwidth selection methods to model DBH structure gave an impulse to present investigation aimed at determining value and variability of smoothing parameter in black alder stands. The optimal bandwidth was obtained according to six different variants of plug−in method proposed by Altman and Léger. Presented investigations were based on DBH measurements collected in 163 managed black alder stands aged from 6 to 89 years, growing in the west part of the Sandomierz Basin (S Poland). We measured in total 22,530 black alders, from 48 to 359 in individual stand. Stands were characterized by: age, quadratic mean diameter, basal area, mean height, Reineke’s stand density index and standard deviation of DBH. Smoothing parameter was obtained by means of plug−in method with the pilot bandwidth selected by: Silverman’s rule of thumb (nrd0), Scott’s method (nrd), unbiased cross−validation (ucv), biased cross−validation (bcv), method of Sheather and Jones (sj) and one−stage method of Wand and Jones (onestage). The bandwidth was first obtained to real data, then to 100 bootstrap samples of 5, 10, 15 ... and 100 trees from each stand. Smoothing parameters were characterized by mean and variance. Relationship between values of smoothing parameter and stand characteristics was determined. Finally the influence of sample size on value and variability of bandwidth was assessed. Value and variability of smoothing parameter in black alder stands are determined by stand age, sample size and method of bandwidth choice. There is a close relationship between bandwidth and the mean height (r from 0.75 to 0.83), quadratic mean diameter (r from 0.79 to 0.88) and standard deviation of DBH (r from 0.84 to 0.93). Potentially these stand features can be used to predict smoothing parameter values. Minor changes of bandwidth for samples containing above 50 trees together with persistence of standard error give an objective grounds for defining optimal number of diameters, that are necessary to kernel estimation of DBH distribution.
    Źródło:
    Sylwan; 2018, 162, 05; 411-421
    0039-7660
    Pojawia się w:
    Sylwan
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Stała krzywa wysokości dla olszy czarnej (Alnus glutinosa (L.) Gaertn.) z zachodniej części Kotliny Sandomierskiej
    Generalized height-diameter model for black alder (Alnus glutinosa (L.) Gaertn.) in the western part of the Sandomierz Basin
    Autorzy:
    Orzeł, S.
    Pogoda, P.
    Ochał, W.
    Powiązania:
    https://bibliotekanauki.pl/articles/991312.pdf
    Data publikacji:
    2014
    Wydawca:
    Polskie Towarzystwo Leśne
    Tematy:
    lesnictwo
    dendrometria
    drzewa lesne
    olsza czarna
    Alnus glutinosa
    piersnice drzew
    wysokosc drzew
    stale krzywe wysokosci
    Kotlina Sandomierska
    alder stands
    height−diameter curve
    local uniform height curve
    the sandomierz basin
    Opis:
    The study shows that the accuracy of tree height approximation by means of investigated functions is not modified by the age or site conditions of the analysed alder stands. The widest range of tree height variability was explained by Schnute (M5) function. Higher values of adjusted coefficient of determination (R²adj) are usually obtained when the height of black alder stands in the western part of the Sandomierz Basin is determined with M2 height−diameter curve.
    Źródło:
    Sylwan; 2014, 158, 11; 840-849
    0039-7660
    Pojawia się w:
    Sylwan
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Dokładność stałych krzywych wysokości dla drzewostanów olszy czarnej (Alnus glutinosa (L.) Gaertn.)
    Accuracy of the uniform height curves for black alder (Alnus glutinosa (L.) Gaertn.) stands
    Autorzy:
    Ochał, W.
    Orzeł, S.
    Siudak, K.
    Zamyślewska, M.
    Powiązania:
    https://bibliotekanauki.pl/articles/989648.pdf
    Data publikacji:
    2016
    Wydawca:
    Polskie Towarzystwo Leśne
    Tematy:
    lesnictwo
    dendrometria
    drzewostany olszowe
    drzewa lesne
    olsza czarna
    Alnus glutinosa
    piersnice drzew
    wysokosc drzew
    stale krzywe wysokosci
    h−d relationship
    uniform height curve
    forest inventory
    black alder
    Opis:
    The study presents the assessment of the accuracy of two generalized height−diameter models, such as skwB [Bruchwald et al. 2001] and skwO [Orzeł et al. 2014], developed in Poland for black alder (Alnus glutinosa (L.) Gaertn.) stands. Verification of these models was conducted on empirical material that was collected in 127 alder stands located in the western part of Sandomierz Basin (southern Poland). Selected alder stands aged 6−89 years, while average breast height diameter ranged from 4.5 to 43.0 cm and average height from 6.3 to 32.7 m. The stand density varied from 222 to 4360 trees/ha. The accuracy assessment for uniform height−diameter curves was based on the analysis of single tree absolute error distributions. Synthetic indicators of goodness−of−fit, such as: average and standard errors, coefficients of variation and determination were calculated based on absolute errors. The final evaluation of the compared uniform height−diameter models results from the structure of the goodness−of−fit measures that was observed within all analyzed stands and within age classes of 20 years. The efficiency of uniform height−diameter models was also compared with stand height−diameter curve, which was developed based on the Näslund function. General height−diameter models overestimated height in alder stands on average from 0.26 (1.67) to 0.19 m (1.39%), based on skwB and skwO models, respectively. Bias depended on the age of stand and decreases from almost 3% in I age class to nearly 0.5% in IV and V age class. For both analyzed models, a positive systematic error was observed for the standardized breast height diameter. Bias in estimating the height of single stand depended on the accuracy of stand height estimations. In case of estimation based on the measurements of three trees height, bias in single stand can range from –13% to +14%. Due to the range and nature of observed systematic errors, uniform height curves should be applied to groups of stands that have different age and breast height diameter structure, as it allows for partial reduction of the error.
    Źródło:
    Sylwan; 2016, 160, 08; 635-646
    0039-7660
    Pojawia się w:
    Sylwan
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
      Wyświetlanie 1-5 z 5

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