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Wyświetlanie 1-6 z 6
Tytuł:
Przesłanki od analizy zmienności siedliska leśnego na podstawie estymacji wysokości drzewostanu
Premisess for analysis of forest site quality dynamics based on tree stand height estimation
Autorzy:
Sypka, P.
Powiązania:
https://bibliotekanauki.pl/articles/60325.pdf
Data publikacji:
2012
Wydawca:
Polska Akademia Nauk. Stowarzyszenie Infrastruktura i Ekologia Terenów Wiejskich PAN
Tematy:
siedliska lesne
bonitacja
mierniki jakosci
drzewostany
wzrost drzewostanu
dynamika wzrostu
modelowanie
wysokosc drzewostanu
estymacja
Opis:
Dynamika wzrostu drzewostanu bardzo silnie zależy od klasy bonitacyjnej siedliska leśnego. Dodatkowo w drzewostanach zagospodarowanych bezzrębowo (odnowienia naturalne) można zaobserwować bardzo duże zróżnicowanie wysokości drzew, zwłaszcza w pierwszych latach ich życia. Drzewa rosnące pod okapem wykazują dość długi okres powolnego wzrostu, co jest głównie spowodowane ocienianiem przez górne piętro drzewostanu. Zgromadzone empirycznie dane wskazują również, że nawet długi powolny wzrost w zagłuszeniu nie uniemożliwia takim drzewom szybkiego wzrostu w późniejszym okresie ich życia. W pracy opisano metodę, pozwalającą określić zarówno zmienność jakości siedliska w czasie, a także szacunkowy czas wzrost w zagłuszeniu. Opracowany algorytm wykorzystuje model wzrostu drzewostanu zaproponowany przez Sulińskiego [2007]. Występujące w tym modelu parametry mają jednoznaczną treść ekologiczną. Weryfikacja metody została przeprowadzona na podstawie danych wysokości drzewostanów świerkowych wzrastających na różnych siedliskach w Puszczy Białowieskiej i Witowie (Tatry Zachodnie).
A site quality index is the main factor determining the tree stand growth dynamics. Furthermore, in natural afforested stands (a felling-less forest system) it is possible to observed high variability of tree heights, especially during the first years of their life. It mainly results from overshadowing the regenerated trees with the upper storey or dominant trees and the growth process is suppressed then. Collected empirical data show that even the long lasting period of growth in suppression does not prevent such a stand from reaching a rapid growth ratio in the later age. The paper presents a method of estimating a forest site quality and a roughly approximated period of the slow growth in suppression. The algorithm was based on the tree stand growth model proposed by Suliński [2007], which takes into consideration only parameters with direct ecological interpretation. The postulated procedure was verified on empirical spruce stand growth benchmarks from experimental sites in the Białowieża forest and Witów in the Western Tatras.
Źródło:
Infrastruktura i Ekologia Terenów Wiejskich; 2012, 3/IV
1732-5587
Pojawia się w:
Infrastruktura i Ekologia Terenów Wiejskich
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Ekologiczne konsekwencje hodowli drzew w różnym zagęszczeniu I. Wzrost i rozwój drzewostanu
Ecological consequences of silviculture at variable stand densities. I. Stand growth and development
Autorzy:
Jagodziński, A.M.
Oleksyn, J.
Powiązania:
https://bibliotekanauki.pl/articles/1012013.pdf
Data publikacji:
2009
Wydawca:
Polskie Towarzystwo Leśne
Tematy:
wzrost drzewostanu
wiezba drzew
zageszczenie poczatkowe
drzewostany
lesnictwo
zageszczenie roslin
rozwoj drzewostanu
stand density
spacing
tree competition
tree biometry
stand growth and development
review
Opis:
The main goal of this review was to characterize ecological consequences of growing trees at variable stand densities. We found that the majority of studies were focused on biometry, productivity and mortality of trees, and wood quality and its economic value, while the influence of stand density on biomass allocation, abiotic and biotic factors, chemistry of different tree organs, diversity and biomass of understory plants, ecophysiology of trees and microclimate conditions (e.g. temperature, humidity, light conditions, etc.) were only occasionally addressed. Stand growth and development trajectories are clearly modified by stand density, however the strength of influence depends on the phase of stand development. Lower seedling densities in nursery conditions lead to increases in their height and diameter, thus influencing seedling quality used in afforestation. The positive influence of higher density on diameter and height of trees in younger stages of stand development may be a result of higher probability of seedlings being planted in more favorable microhabitats, improvement of microclimate conditions, earlier crown closure that reduces interspecific competition for nutrient and water resources. Moreover, stand density clearly influences branch diameter and length, and thus knot size. Higher stand density results in earlier crown closure and higher tree mortality, leading to vertical and horizontal changes in stand structure (DBH, height and crown dimensions of trees). In the denser stands slender and flexible trees with small, narrow crowns dominate, and most of the trees belong to the 3rd class according to Kraft' classification of tree social positions in the stand. The influence of stand density on stand structure may lead to changes in biomass partitioning and thus merchantable wood production and nutrient retention in particular tree organs.
Źródło:
Sylwan; 2009, 153, 02; 75-85
0039-7660
Pojawia się w:
Sylwan
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Wpływ trzebieży na wzrost i produkcyjność drzewostanów sosnowych na przykładzie doświadczenia w Kazlu Ruda (Litwa)
Impact of thinning on the growth and yield of Scots pine stands – a case study from Kazlu Ruda (Lithuania)
Autorzy:
Linkevicius, E.
Bijak, S.
Godvod, K.
Petrauskas, E.
Tiskute-Memgaudiene, D.
Valiukaite, R.
Sapokas, A.
Satinskas, R.
Powiązania:
https://bibliotekanauki.pl/articles/979650.pdf
Data publikacji:
2019
Wydawca:
Polskie Towarzystwo Leśne
Tematy:
lesnictwo
Litwa
drzewostany sosnowe
sosna zwyczajna
Pinus sylvestris
trzebieze
wzrost drzewostanu
produkcyjnosc drzewostanow
scots pine
intermediate cuttings
growth and yield
long−term experiment
Opis:
One of the main tasks for the forest managers is to form the highly productive stands, and it is mainly performed by applying intermediate cuttings during the stand development. As the impact of thinning on the premature Scots pine, commercially most important species in Lithuania, has not been sufficiently investigated yet, our objective was to evaluate the impact of such treatments on the growth and yield of the pine stands by using data from the long term experimental plots. The described thinning experiment was established in 1983 in Kazlu˛ Ru−da (54.760395°N, 23.517736°E), in the 30−years−old Scots pine forest, growing in oligotrophic site conditions. Four square plots with the size of 0.25 ha each were set. The first one (5) was left as a control variant with no thinning, while the others were subjected to the treatments of different intensity. In variant 5A (slightly thinned) 15% of the basal area compared to the control plot was removed. Accordingly, in variant 5B (moderate thinning) 25% and in variant 5C (heavy thinning) 40% of basal area was subtracted. No additional thinning was implemented further during the experiment. Plots were re−measured at least 4 times with the last measurement in 2016, when the stand was 63 years old. The main result of this study was that after the 33 years no evident effect of various intensity of silvicultural treatments can be seen as the growth and yield of the un−thinned forest stand was the highest compared to the thinned ones. Growth and yield in the most intensely thinned stand reached 86 and 85% compared to the control variant, respectively. The best productive results were found for moderate thinning (92 and 89% of growth and yield of the un−thinned stand), while the worst – in the slightly thinned 5A variant (77 and 83% of values for the control stand). Further on, the number of trees and competition level in all plots were very different when the experiment was established. Yet after 33 years, these differences were remarkably reduced. Accordingly, the diameter distributions, being very different at the beginning of the experiment, eventually became very similar in all experimental plots. Finally, the results showed that in un− −thinned forest stand, natural mortality (self−thinning) of trees adjusted its density just in time. Thus this stand managed to keep its growing energy in later periods, avoiding degradation or destruction predicted by some theories.
Źródło:
Sylwan; 2019, 163, 09; 726-739
0039-7660
Pojawia się w:
Sylwan
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Przestrzenne zróżnicowanie dynamiki wzrostu drzew ponad górną granicą lasu na Babiej Górze
Spatial distribution of growth of Norway spruces above the timberline at Mt. Babia Gora
Autorzy:
Michalowicz, P.
Czajka, B.
Kaczka, R.J.
Powiązania:
https://bibliotekanauki.pl/articles/880559.pdf
Data publikacji:
2014
Wydawca:
Szkoła Główna Gospodarstwa Wiejskiego w Warszawie. Leśny Zakład Doświadczalny. Centrum Edukacji Przyrodniczo-Leśnej w Rogowie
Tematy:
gory
Babia Gora
gorna granica lasu
siedliska ponad gorna granica lasu
drzewa
swierk pospolity
Picea abies
struktura wiekowa
wzrost drzewostanu
wzrost roslin
dynamika wzrostu
zroznicowanie przestrzenne
Źródło:
Studia i Materiały Centrum Edukacji Przyrodniczo-Leśnej; 2014, 16, 3[40]
1509-1414
Pojawia się w:
Studia i Materiały Centrum Edukacji Przyrodniczo-Leśnej
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Wzrost drzewostanu sosnowego do fazy tyczkowiny w zależności od sposobu założenia uprawy na gruncie zalesianym
Growth of Scots pine stand to the stage of polewood with regard to the method of culture establishment in the afforested farmland
Autorzy:
Barzdajn, W.
Kowalkowski, W.
Szyguła, J.
Powiązania:
https://bibliotekanauki.pl/articles/986691.pdf
Data publikacji:
2017
Wydawca:
Polskie Towarzystwo Leśne
Tematy:
lesnictwo
hodowla lasu
grunty porolne
zalesianie
uprawy lesne
zakladanie upraw lesnych
metody sadzenia
drzewostany sosnowe
wzrost drzewostanu
przezywalnosc drzewostanow
scots pine
former farmland
planting methods
Opis:
The aim of the study was to compare the growth of plantations established with manual and mechanical methods using planting material of various age. The experiment was established in 2000, in the Góra Śląska Forest District (W Poland) on a former farmland. One− and two−years−old Scots pine seedlings were used. Applied planting methods included: conventional planting bar, German Huff's dibble, trowel, Junack spade and three types of planting machines. The complete random block design with five replications was adopted. For the requirements of machine operation, unit plots were elongated rectangles with the longer side of 100 m and the shorter side of 4.5 m. Each plot consisted of three trenches. Spacing between seedlings in the trench was selected to ensure 10,000 seedlings/ha density. Measurements were carried out in 2000, 2001, 2002, 2003, 2008 and 2015. In the first five dates all heights were measured and seedling survival rates were established based on the number of measurements. In 2008 and 2015 all diameters at breast height were measured. In 2015 height of sample trees was recorded, while the height of the other trees was calculated according to the Prodan model h=d2/(a+bd+cd2)+1.3. Based on the measured diameters at breast height and established heights, basal area at the breast height and total tree volume were calculated for each plot. Survival rate is the primary parameter in the evaluation of planting methods, as it most effectively differentiates treatments. Stand height showed no significant diversification with regard to the treatments. For mean diameters at breast height the only differences were found between two−year old and one−year old seedlings, irrespective of the planting method. Despite the lack of differences in growth, effects of various planting methods and different planting material remain and as a result of high class timber already found in the stand these effects have become economically important. The decision on the selection of a particular planting material type and planting method has extensive economic consequences, as it affects productivity of grown stands at least at the first thinning operations. Planting machines are good tools in the establishment of forest cultures and the quality of their work exceeds that of manual operations.
Źródło:
Sylwan; 2017, 161, 09; 723-729
0039-7660
Pojawia się w:
Sylwan
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Zróżnicowanie bonitacji wzrostowej drzewostanów daglezjowych w Polsce
Variability of the site index of Douglas fir stands in Poland
Autorzy:
Bijak, S.
Powiązania:
https://bibliotekanauki.pl/articles/987057.pdf
Data publikacji:
2017
Wydawca:
Polskie Towarzystwo Leśne
Tematy:
lesnictwo
drzewa lesne
daglezja zielona
Pseudotsuga menziesii
drzewostany daglezjowe
wzrost drzewostanu
bonitacja wzrostowa
siedliska lesne
bonitacja siedliska
gleby lesne
rzezba terenu
Polska
site index
soil type
forest site type
relief features
pseudotsuga menziesii
Opis:
The objective of the study was to analyse the site index (SI) of Douglas fir (Pseudotsuga menziesii) stands in relation to the forest habitat type, soil type and relief characteristics. We utilised infor− mation available in the Information System of the State Forests in Poland that included selected parameters describing habitat conditions and dendrometric characteristics of Douglas fir stands. In total, processed data referred to 863 stands with a total area of 1,644.45 ha. As the SI distribution was not consistent with the normal one (Shapiro−Wilk test, p <0.0001) we applied Kruskal−Wallis or Mann−Whitney tests to assess the significance of observed differences. Site index of surveyed stands ranged from 19.9 to 47.8 m, 32.6 m on average (standard deviation of 3.3 m). Douglas fir in northern and southern Poland characterized by higher SI than in western and south−western part of the country (HK−W=83.5; p<<0.001; fig. 2). Forest habitat type significantly distinguished analysed stands (HK−W=30.1; p<<0.001). The highest SI values were observed for mixed deciduous habitats (fig. 3). For more fertile fresh deciduous habitats Douglas fir achieved slightly lower site index, while the least fertile mixed coniferous habitats are characterized by significantly lower SI. Habitat moisture variant had no significant effect on the average SI values (HK−W=2.6; p=0.269). The highest values were found in strongly fresh habitats (32.8 ±4.1 m), while the lowest in the humid variant (31.7 ±3.4 m). We found significant influence of soil type (HK−W=23.2, p<0.001) even though the average SI values for each category were relatively similar (fig. 4). The highest values were observed for Cambisols (33.3 ±3.7 m), while the lowest for Arenosols (32.1 ±3.0 m). Particle size distribution is an important factor for Douglas fir site index (tab.). We found that the heavier material (the higher the content of silt and clay), the significantly higher SI values (HK−W=16.9; p=0.001). Mean SI for stands growing on former farmlands (32.0 ±3.3 m) and on forest areas (32.7 ±3.3 m) were not significantly different (ZM−W=1.73; p=0.084). There was no significant effect of the relief forms on site index surveyed Douglas fir stands apart from the fact that stands growing on slopes are characterized by significantly higher SI (ZM−W=1.99; p=0.047).
Źródło:
Sylwan; 2017, 161, 03; 208-217
0039-7660
Pojawia się w:
Sylwan
Dostawca treści:
Biblioteka Nauki
Artykuł
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