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    Wyświetlanie 1-7 z 7
    Tytuł:
    Czynniki kształtujące zróżnicowanie przestrzenne pH gleb leśnych na przykładzie gleb płowych podścielonych marglami
    Factors influencing spatial heterogeneity of pH in forest soils on the example of luvisols with marlstone underlayer
    Autorzy:
    Gruba, P.
    Pacanowski, P.
    Mulder, J.
    Powiązania:
    https://bibliotekanauki.pl/articles/993160.pdf
    Data publikacji:
    2013
    Wydawca:
    Polskie Towarzystwo Leśne
    Tematy:
    lesnictwo
    gleboznawstwo lesne
    gleby lesne
    gleby plowe
    odczyn gleby
    zroznicowanie przestrzenne
    wariogramy
    ph
    forest soil
    spatial heterogeneity
    variogram
    Opis:
    Presented investigations focused on spatial variability of forest soil pH on an example of luvisols derived from loess with underlier of marlstones. Four study plots were located in different parts of the slope. Marlstones, present deeper than 1 m under loess layer, had most significant influence on spatial variability of topsoil pH. Despite relatively thick separation from the surface, the marlstone layer altered topsoil via upward water movement (influence distributed evenly) or throughout exposed deeper soil layers as an effect of uprooting (specific island−mosaic of pH). Analysis of spatial variability of soil pH emphasize such phenomena as zero distance variability that reached up to 20% of sill, and 2−4 meters of autocorrelation distances. Thus, there is a need of extended soil sampling to cover both: nugget effect and autocorrelation.
    Źródło:
    Sylwan; 2013, 157, 02; 149-157
    0039-7660
    Pojawia się w:
    Sylwan
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Regionalne zróżnicowanie potrzeb i pilności przebudowy drzewostanów
    Regional diversity of the need and the urgency of stands conversion
    Autorzy:
    Stępień, E.
    Kędziora, W.
    Orzechowski, M.
    Wójcik, R.
    Borecki, T.
    Powiązania:
    https://bibliotekanauki.pl/articles/985680.pdf
    Data publikacji:
    2019
    Wydawca:
    Polskie Towarzystwo Leśne
    Tematy:
    lesnictwo
    drzewostany
    przebudowa drzewostanow
    potrzeby przebudowy
    zroznicowanie regionalne
    regionalne dyrekcje Lasow Panstwowych
    stand classification
    regional heterogeneity
    conversion necessity
    state forests
    Opis:
    Nowadays in forestry, we observe an increase in threats that rise the uncertainty and risk of the forest management. This is caused, inter alia, by increasing intensity of forest and environmental damage as well as by the conflict of expectations for the use of forest resources. As a result, there is a problem of achieving the goals of sustainable development and adaptation of the forest ecosystems to new challenges. The aim of the presented study was to assess the regional variety of the need and the urgency of stands conversion. The feature was determined for all stands of the State Forests older than 20 years. Three assessment criteria were selected: (A) silvicultural target (compatibility of the species composition with the planned one), (B) stands stability (resultant from 5 auxiliary sub−indices), and (C) stock level (including 2 auxiliary sub−indices). The majority of stands has consistent species composition (over 60% in total), however only a small fraction of stands was found with a species composition incompatible with the planned one (average 6.34%). Stands with medium stability accounted for about 70%, while those with poor growing stock status make up about 70% of stands under analysis. The regional diversification of the needs for stands reconstruction seems to be strongly correlated with the incompatibility of stand’s species composition with habitat conditions. The largest fraction of stands requiring conversion was observed in Wrocław, Kraków and Katowice regional directorates of the State Forests. This situation may change in the future due to dynamic changes resulting from modifications of the climate and the deterioration of health condition of dominant Scots pine stands in central and north parts of Poland. Private forests were not taken into consideration in this research. It may impact the overall picture in regions of the high share of private forest ownership.
    Źródło:
    Sylwan; 2019, 163, 04; 267-278
    0039-7660
    Pojawia się w:
    Sylwan
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Rola sójki (Garrulus glandarius) w inicjowaniu przemian sukcesyjnych zbiorowisk leśnych z udziałem dębu (Quercus sp.)
    Role of jay (Garrulus glandarius) in initializing successional changes in forest communities with the participation of oak (Quercus sp.)
    Autorzy:
    Olszewski, A.
    Brzeziecki, B.
    Powiązania:
    https://bibliotekanauki.pl/articles/980357.pdf
    Data publikacji:
    2019
    Wydawca:
    Polskie Towarzystwo Leśne
    Tematy:
    lesnictwo
    zbiorowiska lesne
    sukcesja roslin
    dab
    Quercus
    zoochoria
    sojka
    Garrulus glandarius
    acorn
    jay
    oak
    ornitochory
    seed dispersal
    stand heterogeneity
    tree succession
    zoochory
    Opis:
    The ability of spatial expansion and conquering of new locations, suitable for growth, is one of the most important properties enabling different plant species (including forest trees) a permanent existence in a constantly changing (in space and in time) environment. In the course of evolution, plants developed several adaptations and mechanisms enabling them to capture new localities appropriate for life. The key role in this process is played by so called propagules, i.e. differently built spores, seeds and fruits. The main sources of forces and major transportation vectors for propagules are such mechanisms as: power of gravity (barochory), wind (anemochory), water (hydrochory), animals (zoochory) and man (antropochory). Among them, in case of tree species producing large seeds, containing bulky amounts of food resources, the most important role is played by zoochory. The special variant of zoochory is ornitochory, i.e. dispersion of plant propagules by birds. One of the best known and documented examples of ornitochory is dispersal of oak acorns by jays (Garrulus glandarius). The contemporary research shows that during a vegetation period one single bird is able to deposit even several thousends of acorns within the area of 10 to 100 ha. The dispersal distance in case of acorns distributed by jays is variable and depends on several factors, first of all, climatic conditions and degree of environmental heterogeneity. On average, acorns are distributed within a distance of several hundred meters from seed trees; sometimes they are disseminated at a distance of several (4−8, maximum 20) kilometers. As a rule, only a part of deposited acorns is uncovered and consumed by birds, thus at least some of them can germinate and produce new oak seedlings. It was also recently demonstrated that jays preferably put down acorns under the stand canopies composed by tree species other than oak, for instance, under Scots pine trees. Under favourable conditions, this initiates natural successional processes and leads to a significant conversion of tree stand composition. Considering a large scale and commonness of this phenomenon, it deserves an interest and attention, not in the case of natural forests only, but in the case of managed forests as well, in which the quasi−natural, successional processes, initiated by jays, can considerably contribute to a greater compositional and structural diversity of tree stands.
    Źródło:
    Sylwan; 2019, 163, 06; 479-88
    0039-7660
    Pojawia się w:
    Sylwan
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    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:
    Wybrane metody badania struktury przestrzennej drzewostanów o niejednorodnym zagęszczeniu
    Selected methods for spatial structure analysis of tree stands with heterogeneous tree density
    Autorzy:
    Bolibok, L.
    Gil, W.
    Powiązania:
    https://bibliotekanauki.pl/articles/994345.pdf
    Data publikacji:
    2013
    Wydawca:
    Polskie Towarzystwo Leśne
    Tematy:
    lesnictwo
    drzewostany
    struktura drzewostanu
    struktura przestrzenna
    zageszczenie niejednorodne
    schematy wiezbowe Neldera
    dane przestrzenne
    analiza danych
    funkcja Ripleya
    funkcja korelacji par
    ripley's k(t) function
    pair correlation function
    heterogeneity
    k2 function
    point pattern analysis
    Opis:
    Paper compares various analysis methods suitable for an analysis of point pattern with directionally varying point density. As example was used point pattern from spacing experiment created according to Nelder design in which tree density changes greatly but in smooth manner. Such a pattern could be not analysed by methods assuming homogenous point density e.g. classical estimator of Ripley's K function. More useful are estimators of Ripley's and pair−correlation functions for inhomogeneous point patterns. K2 function, which proved to be efficient for heterogeneous point patterns with distinct changes in the local point density appears not to be efficient for heterogeneous point patterns with smooth changes in density.
    Źródło:
    Sylwan; 2013, 157, 08; 618-629
    0039-7660
    Pojawia się w:
    Sylwan
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Tekstura karpackiego dolnoreglowego drzewostanu mieszanego o charakterze pierwotnym
    Texture of a primeval lower montane mixed forest in the Carpathians
    Autorzy:
    Kołodziej, Z.
    Paluch, J.
    Bartkowicz, L.
    Pach, M.
    Powiązania:
    https://bibliotekanauki.pl/articles/989790.pdf
    Data publikacji:
    2015
    Wydawca:
    Polskie Towarzystwo Leśne
    Tematy:
    lesnictwo
    Babiogorski Park Narodowy
    regiel dolny
    drzewostany mieszane
    drzewostany swierkowo-bukowo-jodlowe
    las pierwotny
    tekstura drzewostanu
    sklad gatunkowy
    drzewa lesne
    liczba drzew
    piersnicowe pole przekroju
    primeval forest
    mixed stands
    spatial pattern
    structural heterogeneity
    diversity index
    forest dynamics theory
    Opis:
    The aim of this study was to characterize the texture of a primeval forest composed of Fagus sylvatica (L.), Abies alba (Mill.) and Picea abies ((L.) H. Karst). Empirical data were collected in the Babia Góra National Park (southern Poland) in the stand being under strict protection since 1934. 259 circular plots with a radius of 7.0 m and an area of 154 m² each were established in nodes of 20×20 m grid. For individual plots and blocks of the combined plots representing gradient of spatial scales between 0.015 and 0.640 ha, the number of trees, diameter at breast height (dbh) distributions, basal areas and the values of structural diversity indices of Gini (GI), Shannon (SH) and Staudhammer−LeMay (STVI) were determined. The indices were also calculated for several types of theoretical distributions. Based on the values obtained for the theoretical distributions, the individual plots and the blocks of the combined plots were classified as representing simple (GI≤0.30;STVI≤0.10), moderately diversified (0.300.45; STVI>0.30) dbh structure. For all the spatial scales analyzed the average values of GI and STVI indices reached the level typical for populations of a high structural diversity (i.e. exceeded the values of 0.45 and 0.30 respectively). According to the GI and STVI values, the portion of stand patches with complex dbh structure ranged from 70.9% and 68.2% at the individual plots scale, respectively, up to 100% in the blocks of 16 plots (4×4). In general, in all the spatial scales analyzed the spatial diversification of the dbh distributions and basal area levels was higher than in managed selection forests and much higher than in managed single−storied stands. The dominant frequency of highly diversified dbh distributions found in the analysed stand was not concordant with the predictions of the forest dynamics theory based on developmental stages, according to which in primeval forests with a significant partition of Abies alba and Picea abies should prevail stand patches of rather simple dbh structure, characteristic for the long−lasting optimum stage.
    Źródło:
    Sylwan; 2015, 159, 07; 600-609
    0039-7660
    Pojawia się w:
    Sylwan
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Przestrzenna zmienność struktury drzewostanu w wybranych lasach o charakterze pierwotnym w Karpatach Zachodnich i Górach Dynarskich
    Spatial variation in stand structure of selected old-growth forests in the Western Carpathians and the Dinaric Mountains
    Autorzy:
    Paluch, J.
    Bartkowicz, L.
    Powiązania:
    https://bibliotekanauki.pl/articles/979198.pdf
    Data publikacji:
    2020
    Wydawca:
    Polskie Towarzystwo Leśne
    Tematy:
    lesnictwo
    lasy o charakterze pierwotnym
    struktura drzewostanu
    analiza porownawcza
    Karpaty Zachodnie
    rezerwat Oszast
    rezerwat Perucica
    Gory Dynarskie
    leśnictwo
    lasy góskie
    pierśnicowe pole przekroju
    zmienność przestrzenna
    Beskid Żywiecki
    rezerwat Żarnówka
    old−growth forests
    primeval forests
    natural forest dynamics
    structural heterogeneity
    patch−mosaic
    developmental stages
    continuous cover forestry
    Opis:
    The research was conducted in three old−growth forests consisted of silver fir Abies alba Mill., European beech Fagus sylvatica L., and Norway spruce Picea abies Karst. located in the southern part of Poland (Żarnówka and Oszast) and the south−eastern Bosnia and Hercegovina (Perućica). The aim of the study was to compare basic stand characteristics and spatial heterogeneity in terms of variation in stand basal area and vertical structure. In each research area, small sample plots (0.015 ha) were localised in a regular 20×20 m grid covering approximately 10 ha. In each sample plot the diameter at breast height (d1.37 cm) and species of all live trees were recorded. For each plot the basal area of live trees and an index of structural diversification were determined. As a measure of structural diversification, the simple variance in tree height was computed and scaled through comparison with a hypothetical variance of the uniform distribution. The spatial patterns of basal area and structural diversification were tested with paired−plot approach. In addition, simulation techniques were used to model variation in the basal area of live trees dependent on spatial scale. The Carpathian and Dinaric stands considerably differed in basal area (ranging from 36.1 to 65.2 m2/ha) and volume (varying from 522 to 1176 m3/ha), but all of them had diameter distributions proximate to a negative exponential model. The basal area recorded on the 0.015 ha plots had a very similar pattern of variation, which could be generalised as a truncated normal distribution. The distribution of the structural diversification index was different and resembled an uniform (Perućica) or a bimodal distribution with modal values at its extremes (Oszast and Żarnówka). However, in the spatial scales above 1,000 m2 the index distri− bution become similar to a normal (Oszast) or a truncated normal (Perućica and Żarnówka) ones with high mean values, indicating the predominance of complex vertical structures. In general, the spatial variability in basal area and structural diversification of live trees tended to be random. These results suggest that the patch−mosaic assumption being fundamental for the developmental cycle hypothesis is inapplicable to the studied primeval forests. Regardless of differences in geographic location and site conditions, the studied stands show a similar spatial pattern of structural heterogeneity, suggesting a close resemblance of disturbance regimes driving its dynamics.
    Źródło:
    Sylwan; 2020, 164, 02; 91-101
    0039-7660
    Pojawia się w:
    Sylwan
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
      Wyświetlanie 1-7 z 7

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