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Wyświetlanie 1-2 z 2
Tytuł:
Czy naturalne procesy ekologiczne w juwenilnej fazie rozwoju drzewostanu założonego sztucznie różnicują jego strukturę przestrzenną?
Do natural processes at the juvenile stage of stand development differentiate the spatial structure of trees in artificially established forest stands?
Autorzy:
Szmyt, J.
Korzeniewicz, R.
Powiązania:
https://bibliotekanauki.pl/articles/1317220.pdf
Data publikacji:
2014
Wydawca:
Instytut Badawczy Leśnictwa
Tematy:
lesnictwo
ekologia lasu
drzewostany sosnowe
drzewostany debowe
wiezba poczatkowa
procesy ekologiczne
wydzielanie sie drzew
drzewa lesne
sosna
dab
rozmieszczenie drzew w przestrzeni
piersnice drzew
wysokosc drzew
dlugosc korony
spatial indices
forest diversity
self-thinning
managed forests
Opis:
Structural diversity is one of the most interesting phenomena that have been studied by forest ecologists and practitioners. Amongst the different characteristics of forest structure, spatial diversity of trees and their attributes seem to be very important. The more spatially structured a population is, the higher its diversity in terms of size and species richness. Because most forests in Europe are managed and were artificially established, they are subjected to conversion processes turning them into more complex systems. The approach presented here aims at elucidating whether natural processes, such as self-thinning, can cause the self-differentiation of spatial structure in artificially planted stands. Our analyses focused on untended Scots pine and pedunculate oak stands in the juvenile phase of development and were based on spatially explicit structural indices for positioning and size differentiation (diameter, total height and crown length). The obtained results indicate that live trees were dispersed more or less regularly. Unlike the anglebased index, which mostly indicated randomness in tree location, a distance-based index showed clear regularity. We also found that the distribution of tree attributes auto-correlates to tree location as indicated by significantly lower index values compared to values resulting from random reassignment of the examined attributes. This low degree of spatial differentiation is further confirmed by the distribution of indices in differentiation classes. Our results allow us to conclude that, in the case of light demanding species (pine and oak), natural processes do not increase spatial diversity of the stand, although, both species showed a certain degree of deviation in this respect.
Źródło:
Leśne Prace Badawcze; 2014, 75, 2; 171-179
1732-9442
2082-8926
Pojawia się w:
Leśne Prace Badawcze
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Związki między wybranymi cechami drzewa a niektórymi właściwościami drewna młodocianego sosny zwyczajnej (Pinus sylvestris L.)
Relationships between selected tree characteristics and the properties of juvenile wood in Scots pine (Pinus sylvestris L.)
Autorzy:
Tomczak, A.
Powiązania:
https://bibliotekanauki.pl/articles/1312952.pdf
Data publikacji:
2014
Wydawca:
Instytut Badawczy Leśnictwa
Tematy:
lesnictwo
drzewa lesne
sosna zwyczajna
Pinus sylvestris
cechy morfologiczne
wysokosc drzew
piersnice drzew
wysokosc osadzenia pierwszej zywej galezi
srednica korony
dlugosc korony
drewno sosnowe
drewno mlodociane
gestosc drewna
gestosc umowna
wytrzymalosc na sciskanie wzdluz wlokien
wytrzymalosc na zginanie statyczne
modul elastycznosci przy zginaniu
korelacja cech
basic density
strength perpendicular to grain
bending strength
modulus of elasticity
breast height
diameter
tree height
crown length
crown diameter
Opis:
The aim of this study was to determine relationships between selected properties of juvenile wood and characteristics of the stem and crown of Scots pine. Analyses were conducted in northern Poland in eight mature pine monocultures. Nine trees were selected in each experimental site and their stems were divided into five sections. The centers of the sections were established at a height of 1.3 m from the tree base and at points corresponding to 20, 40, 60 and 80% tree height. Samples were taken from these locations, and these samples were prepared for analyses of basic density, compressive strength along the grain and static bending, as well as the modulus of elasticity during bending. The mean height of the investigated group of trees was 26.0 m with an average diameter breast high of 33.6 cm. The mean crown depth was 7.8 m and crown diameter was 3.6 m, and the mean basic density (Qu) of juvenile pine wood was 416 kg/m3. The average compressive strength along the grain (CS) was determined to be 22.3 MPa, while static bending strength (BS) was 45.8 MPa. The recorded modulus of elasticity (MOE) was 4726 MPa. Both in general terms and when dividing stems into sections, the wood properties correlated with tree characteristics to various degrees. All indexes were negative indicating that trees of greater dimensions produce juvenile wood of inferior quality. Properties of juvenile wood formed during various periods of tree life were mostly related to diameter breast high and crown depth. They were also correlated with tree height, but only to a limited extent. In contrast, properties of wood from the middle stem sections were significantly correlated with crown diameter.
Źródło:
Leśne Prace Badawcze; 2014, 75, 3; 237-244
1732-9442
2082-8926
Pojawia się w:
Leśne Prace Badawcze
Dostawca treści:
Biblioteka Nauki
Artykuł
    Wyświetlanie 1-2 z 2

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