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Wyszukujesz frazę "threat to forests" wg kryterium: Temat


Wyświetlanie 1-2 z 2
Tytuł:
Zmiany zachodzące w lasach Beskidu Małego
Changes occurring in the forests of the Beskid Maly Mts.
Autorzy:
Dmyterko, E.
Bruchwald, A.
Powiązania:
https://bibliotekanauki.pl/articles/979504.pdf
Data publikacji:
2019
Wydawca:
Polskie Towarzystwo Leśne
Tematy:
lesnictwo
gory
Beskid Maly
lasy gorskie
drzewostany swierkowe
rozpad drzewostanow
struktura drzewostanu
struktura gatunkowa
struktura wiekowa
pozyskiwanie drewna
zlomy
wywroty
zagrozenia drzewostanow
changes in species composition
decrease in the proportion of spruce
threat to forests
Opis:
Like in the Beskid Śląski and Żywiecki Mts., the dieback of Norway spruce stands takes place also in the Beskid Mały range. This process is clearly more intensive and occurs over a longer period of time. The conversion of these forests during the study period (2004−2016) resulted in a significant increase in the proportion of beech and fir as well as other, mostly deciduous tree species (tab. 1). The dieback of spruce forests is likely to continue, as the share of spruce in some forest complexes is still high. The age class structure of forests during the study period was found to have a negative effect on the stability and uniformity of forest growth – the young stands fraction was too low and decreased (tab. 3). The high average age of stands, which increased from 67 in 2007 to 71 years in 2016 was also unfavourable. The volume of harvested timber was rather high and approximated to the volume of allowable cut determined by the stand growth model (so−called model volume) (figs. 1, 2). In the Andrychów Forest District the harvested volume was significantly lower than the model volume, while in Jeleśnia and Bielsko districts it was significantly higher, which results from higher proportion of spruce in these regions. In the harvested timber structure, the share of wind−broken and wind fallen trees was about 10%, which is not high for the mountain area (fig. 3). The exception was in year 2005, when timber removals after the hurricane of November 2004 were estimated at more than 30%. In 2006−2008, the volume of deadwood was high and consisted mainly of spruce (fig. 4). Then the dieback of spruce forests decreased and was observed predominantly in the western and southern parts of the forest complex. The years 2013−2016 saw a high share of live trees in the harvested timber volume (over 80% of the model volume) (fig. 5). In some parts of the Beskid Mały forests, the harvest of live trees exceeded 300% of the model volume. Such high harvest is justified by the need of urgent silvicultural tasks to be carried out, especially stand conversion. The threat to the Beskid Mały forests from wind is high and remained at the same level throughout the study period – the threat measure Ms was ca. 33 (fig. 6). It is essential to lower the level of threat to these forests by, inter alia, increasing the area of young stands.
Źródło:
Sylwan; 2019, 163, 03; 237-247
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
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