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Wyszukujesz frazę "forest age" wg kryterium: Temat


Wyświetlanie 1-2 z 2
Tytuł:
Dynamika i główne kierunki zmian w drzewostanach zagospodarowanej części Puszczy Białowieskiej
Dynamics and main direction of change in forest stands constituting the managed part of Bialowieza Forest
Autorzy:
Bruchwald, A.
Dmyterko, E.
Brzeziecki, B.
Powiązania:
https://bibliotekanauki.pl/articles/985942.pdf
Data publikacji:
2018
Wydawca:
Polskie Towarzystwo Leśne
Tematy:
lesnictwo
Puszcza Bialowieska
drzewostany gospodarcze
dynamika drzewostanu
siedliska lesne
struktura drzewostanu
sklad gatunkowy
struktura wiekowa
miazszosc drzewostanow
przyrost miazszosci
abiotic and biotic threats
forest age structure
low−productivity stands
stand productivity
stand volume
stand stability
species composition
wind risk model
Opis:
The paper describes current (in years 2007−2017) changes of basic parameters of forest stands that constitute the managed part of Białowieża Forest (ca. 53,000 ha), divided into three forest districts: Białowieża (12,600 ha), Hajnówka (19,700 ha) and Browsk (20,400 ha). The investigated tree stands represent different phases of ecological succession, modified by silvicultural treatments and other human activities. The course of the succession processes is varied, depending, first of all, on local site conditions, consisting mainly of fresh sites (ca. 60%) – particularly fresh broadleaved forest, and encompassing exceptionally high fraction of wet and swamp sites (40%) – especially wet broadleaved forest site type. Most stands represent the intermediate, highly productive phase of succession, with spruce and oak as the dominant tree species. In particular, such stands are common in Białowieża and Hajnówka forest districts. Recently, the share of the mentioned stands is declining, most intensely in the Browsk Forest District. In 2017 alone, 430 ha of highly productive forest stands disappeared from the Białowieża Forest. The process of decay involved mixed stands; besides of spruces which were killed by a current bark beetle infestation, also many oaks, pines, birches, alders as well as rare and valuable minor tree species (such as ashes and maples) died. Dying spruce and, more often, oak stands are often replaced by low−productive hornbeam trees, occupying earlier lower stand strata in such stands. The resulting hornbeam stands are often distinguished by low crown closure and low productivity. Tree stands occurring in the Białowieża Forest are among the most endangered by wind damage stands in Poland. It means that in case of strong winds, several trees will be broken and/or uprooted. The intensity of such phenomena will be further increased by the high tree volume of stands as well as by the presence of many gaps in forest canopy, caused by a massive mortality of spruce trees. In general, one may expect that in the nearest future many stands occurring in the Białowieża Forest, built by different tree species, will be subject to a massive decay. The list of factors contributing to this process is long and involves, among other things, recurring droughts during the growing season, unfavorable changes in ground water table and increased frequency of strong winds. All these factors negatively influence the health status of trees, which further favours the development of parasitic fungi and insects. In consequence, there is a high probability that many areas in the Białowieża Forest will, for a long time, retain a treeless character and/or will be occupied by low−productive and single species hornbeam stands.
Źródło:
Sylwan; 2018, 162, 11; 897-906
0039-7660
Pojawia się w:
Sylwan
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Rozpad drzewostanów świerkowych w Beskidzie Żywieckim
Dieback of Norway spruce stands in the Beskid Zywiecki Mts.
Autorzy:
Dmyterko, E.
Bruchwald, A.
Mionskowski, M.
Powiązania:
https://bibliotekanauki.pl/articles/979601.pdf
Data publikacji:
2019
Wydawca:
Polskie Towarzystwo Leśne
Tematy:
lesnictwo
Beskid Zywiecki
drzewostany swierkowe
rozpad drzewostanow
swierk pospolity
Picea abies
struktura drzewostanu
struktura wiekowa
struktura gatunkowa
pozyskiwanie drewna
struktura pozyskania
zagrozenia lasu
wiatry
szkody od wiatru
forest dieback
picea abies
species structure
age structure
timber harvest
threat to forests by wind
Opis:
In the Beskid Żywiecki, the combination of abiotic, biotic and anthropogenic factors unfavourable for the growth of trees led to the dieback of spruce stands. The intensification of this process began after the hurricane in November 2004, followed by years of negative climatic water balance. The deterioration of tree growth conditions occurred after the drought in July 2006 and damage caused by the Kyril hurricane in January 2007. The weakened spruces were attacked by the bark beetles, the outbreak of which caused a massive dieback of spruce stands. In order to assess the volume of harvested timber in years 2004−2016, the volume of allowable cut (model volume) was calculated from the stand growth model for each forest district of Beskid Żywiecki. The comparison of the volume of harvested timber with the model volume allowed to determine the rate of dieback of spruce stands. The volume of harvested timber in 2007−2009 exceeded the model volume even 2.5 times. The cuts included mainly deadwood, wind−broken and wind−fallen trees, while the harvest of live trees was scarce. In the period 2010−2013, the harvested volume of live trees accounted for 50−70% of the model volume, the volume of deadwood in the same period was ca. 100% and additionally the volume of blown−down timber after the hurricane was 20−40% of the model volume, which taken together accounted approximately to 200% of the model volume. The execution of such harvesting operations, including silvicultural tasks, did not allow to carry out optimal forest management. The period 2010−2013 saw a downward trend. It was disrupted by the hurricane in December 2013, after which the volume of harvested timber, consisting mainly of wind−broken and wind−fallen trees, increased to 280% of the model volume. Again, the high volume of harvested timber was noted in 2016, (ca. 220% of the model volume). The process of damage to spruce stands in Beskid Żywiecki is likely to continue. A decline in its intensity may occur in the absence of old stands, which to a large extent already takes place in the forests of the Węgierska Górka Forest District. Currently, the most threatened by wind are forests in Ujsoły, Jeleśnia and Nowy Targ forest districts. The least threatened are forests in the Węgierska Górka. This forest district and in the future the remaining forest districts of Beskid Żywiecki, will face enormous challenges to obtain high yield and appropriate species composition.
Źródło:
Sylwan; 2019, 163, 02; 130-140
0039-7660
Pojawia się w:
Sylwan
Dostawca treści:
Biblioteka Nauki
Artykuł
    Wyświetlanie 1-2 z 2

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