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    Tytuł:
    Zastosowanie modelu ryzyka uszkodzenia drzewostanu przez wiatr do oceny procesu śmiertelności drzew w Sudetach w latach 2015-2017
    Application of the wind damage risk model for the assessment of tree mortality in the Sudety Mts. in 2015-2017 period
    Autorzy:
    Dmyterko, E.
    Bruchwald, A.
    Powiązania:
    https://bibliotekanauki.pl/articles/979365.pdf
    Data publikacji:
    2019
    Wydawca:
    Polskie Towarzystwo Leśne
    Tematy:
    Sudety
    drzewostany
    wiatry
    szkody w lesie
    ryzyko uszkodzenia
    modele ryzyka uszkodzenia
    zamieranie drzew
    czynniki klimatyczne
    lata 2015-2017
    leśnictwo
    drzewa leśne
    RDLP Wrocław
    tree mortality
    critical value of deadwood harvest
    wind damage risk model
    forest threat measure
    Opis:
    A dynamic process of mortality of Norway spruce stands in south−west Poland, mainly in the Sudety Mts. was observed in 2015. It was associated with an insufficient amount of precipitation in the growing season. This process was intensified by the outbreak of insects, especially bark beetles. The aim of the paper was to verify the hypothesis that the application of the stand damage risk model allows to identify stands, which may possibly be predisposed to mortality, after a long−lasting drought in the growing season. The studies concerned the forests of the Wrocław Regional Directorate of State Forests (tab. 1). Their area covers 245,000 ha, the timber volume amounts to 83 million m3 (338 m3/ha) and the volume increment to 2.3 million m3 (9.4 m3/year/ha). The fraction of spruce is the largest (50.3%), ranging from 7.1% (Pieńsk Forest District) to 84.8% (Lądek−Zdrój Forest District). The average age of stands is 74 years, ranging from 56 (Pieńsk Forest District) to 85 years (Jawor Forest District). The drought in 2015 caused an increase in the dynamics of spruce decline. The ratio of harvested to model deadwood volume at a level of up to 5% was assumed the ‘norm’ that characterizes the process of natural spruce mortality. Values higher than normal mean a more intense process of tree mortality caused by external factors (e.g. hurricane winds, floods, droughts). In 2014, the harvested deadwood was below the norm in 15 forest districts (fig. 1). In 2015, the highest ratio values (above 20%) were reported in the Wałbrzych and Szklarska Poręba forest districts (fig. 1). In 2016, the harvest of deadwood in each forest district exceeded the norm, and the highest values were found in the Jawor (102.3%), Bardo Śląskie (83.3%) and Świdnica (69.7%) forest districts. In 2017, the highest ratios of harvested to model deadwood volume were reported in the Bardo Śląskie (117.2%), Jawor (83.6%), Henryków (83.5%) and Świdnica (67.1%) forest districts. The model was found to identify also the stands that are most threatened by droughts. These are stands in the highest damage risk factor Wr class. The highest percentage of deadwood in this damage class was in Jawor (88.8%), Bardo Śląskie (81.9%), Miękinia (79.4%), Świdnica (76.7%), Henryków (73.8) and Złotoryja (73.6%) forest districts. It was also shown that the average value of the measure of threat to forests Ms was 35, qualifying them as highly threatened (fig. 3). Forests characterized by the highest level of threat Ms>40 was found in five forest districts, while in nine others the level of threat was high. The forests of the Sudety Mts. are threatened by the decline and the main direct causes of this process was the long−lasting drought in the growing season, causing damage to the stands earlier weakened by wind and other factors.
    Źródło:
    Sylwan; 2019, 163, 11; 903-912
    0039-7660
    Pojawia się w:
    Sylwan
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Zmiany zachodzące w drzewostanach Bieszczadów
    Changes in the forests of the Bieszczady Mts.
    Autorzy:
    Dmyterko, E.
    Bruchwald, A.
    Powiązania:
    https://bibliotekanauki.pl/articles/985915.pdf
    Data publikacji:
    2018
    Wydawca:
    Polskie Towarzystwo Leśne
    Tematy:
    lesnictwo
    lasy gorskie
    Bieszczady
    drzewostany
    sklad gatunkowy
    zmiany w drzewostanach
    zmiany skladu gatunkowego
    model wzrostu drzewostanu
    modele ryzyka uszkodzenia
    species composition
    stand growth model
    model allowable cut
    wind damage risk model
    forest threat
    measure
    Opis:
    The aim of the study was to analyse (on the basis of the data from the State Forests Information System) the changes occurring in the Bieszczady forests in the period of 2007−2016. One of the processes taking place in the study area is the withdrawal of grey alder stands and the appear− ance of natural regeneration of mainly beech and fir, and in a smaller proportion spruce (fig. 1). Another natural process is the encroachment of fir and beech under the canopy of pine stands, which is favoured by fertile habitats that meet the ecological requirements of these two tree species. As a result of economic activity supporting these processes, alder and pine stands are being rebuilt relatively quickly, turning into fir or beech stands, and sometimes into mixed stands with the participation of other tree species, including spruce (fig. 1). The decline of spruce stands occurs on the dominant area in Poland: in Beskid Śląski and Beskid Żywiecki, the Kaszuby Forest or the Białowieża Forest. The main causes of this process are abiotic and biotic factors, including frequent droughts causing the lowering of the groundwater level and insect outbreaks, especially of bark beetles. The proportion of spruce in the Bieszczady Mountains is relatively small (about 10%), and the high fertility of the habitats compensates, to some extent, the relatively high moisture requirements of this tree species and probably these factors determined the lack of decline of spruce stands in the analysed area. In the last 10 years, the average age of forests in the Bieszczady Mountains increased from 77 to 83 years (tab. 2), mainly as a result of too low volume of harvested timber (fig. 3). Comparing the total harvested volume with the volume of allowable cut determined by the stand growth model, the harvest of the wood raw material was understated by about 25%. The aging of forests is also confirmed by changes in stands in age classes (fig. 2). The aging of the Bieszczady forests is correlated with the process of increasing the threat to these forests by wind (figs. 4−5). The wind damage risk factor increased over the next 10 years in the two highest threat level, and thus the area of threatened stands increased. The forest threat measure in the Bieszczady forests increased in general as well as in individual forest districts (fig. 6). The forests in two of these districts are currently among the most threatened in Poland.
    Źródło:
    Sylwan; 2018, 162, 05; 355-364
    0039-7660
    Pojawia się w:
    Sylwan
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
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