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Wyszukujesz frazę "model composition" wg kryterium: Wszystkie pola


Wyświetlanie 1-5 z 5
Tytuł:
Model składu gatunkowego drzewostanu dla lasów w Sudetach z uwzględnieniem zmian klimatycznych
Species composition model for the forests of the Sudety Mountains with regard to climate change
Autorzy:
Dmyterko, E.
Bruchwald, A.
Mionskowski, M.
Brzeziecki, B.
Powiązania:
https://bibliotekanauki.pl/articles/979139.pdf
Data publikacji:
2020
Wydawca:
Polskie Towarzystwo Leśne
Tematy:
abiotic and biotic factors
climatic change
forest damage
forest functions
stand composition
Opis:
Climate change creates a big challenge for forest science. One of several problems calling for urgent solution concerns the elaboration of the scientific foundations for determination of the species composition of forest stands under changing environmental conditions. This problem is particularly acute in case of declining Norway spruce stands in the Sudety Mountains (SW Poland). The paper presents the main principles used to develop a model allowing determination of the most desirable species composition for any given forest stand occurring in the Sudety region. These principles include: 1) an assumption that a basis for species composition planning should be a forest site type, corrected by means of site index of the currently existing forest stand, 2) a supposition that one should broadly consider present processes taking place in Sudety stands, particularly, an intense forest dieback caused by recurring drought periods and strong winds, 3) a postulate that one should consider the differences between tree species in respect to their reaction to particular abiotic factors, 4) an assumption that majority of stands should consist of several different tree species, 5) an assumption that introducing on a wide scale Douglas fir, well−adapted to the conditions of the Sudety Mountains, is allowed, 6) an idea that one should take into account differentiated production potential and varied timber quality of particular tree species, 7) an assumption that one should consider the main features of topography (altitude, exposition, slope) as well as 8) fine elements of micro−topographical situation, as a basis for introduction of different tree species. The results obtained by means of the model based on the above mentioned principles are presented on the example of two forest districts: Lądek−Zdrój (fig. 4a, b) and Szklarska Poręba (fig. 5a, b). In both cases, a necessity to diminish the share of Norway spruce and to increase the share of such species like common beech, silver fir, Douglas fir and European larch is demonstrated. One may expect that projected compositions, taking into account the most appropriate tree species and their most suitable localizations, will allow establishment of forest stands which will be more resistant to drought and wind and, thus, will be more able to fulfill several important forest functions (related to water and soil protection, protection of forest biodiversity and timber production).
Źródło:
Sylwan; 2020, 164, 06; 454-466
0039-7660
Pojawia się w:
Sylwan
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Podstawy planowania składu gatunkowego w lasach górskich na przykładzie Beskidu Niskiego
Basis of the species composition planning model for mountain forests on the example of Beskid Niski Mts.
Autorzy:
Bruchwald, A.
Dmyterko, E.
Mionskowski, M.
Niemczyk, M.
Łukaszewicz, J.
Powiązania:
https://bibliotekanauki.pl/articles/972988.pdf
Data publikacji:
2016
Wydawca:
Polskie Towarzystwo Leśne
Tematy:
hodowla lasu
planowanie
czynniki siedliska
typy siedliskowe lasu
leśnictwo
tereny górskie
lasy górskie
skład gatunkowy
wysokość nad poziomem morza
rzeźba terenu
species composition
habitats
landforms
mountain forests
Opis:
The study presents a method of planning species composition of forest stands in mountain areas on the example of Beskid Niski Mts. (south−eastern Poland). The focus was on the species composition of forest stands growing in different conditions, taking into account the type of forest habitat and terrain characteristics: altitude, exposition and slope. The research was based on data stored in the Information System of the State Forests. We used modified growth model for data processing and calculation of site index for the forests older than 60 years. The Beskid Niski Mts. are covered mostly by European beech (33.8%), silver fir (28.3%) and Scots pine (18.9%). Taking into account exclusively the productive capacity of individual forest stands, fir and spruce would be the most desirable species in analysed region. The Beskid Niski Mts. are characterized by a very small diversity of the habitat with domination of mountain fresh deciduous forest (LGśw, 92.1% of the area). We divided analysed region into four altitudinal zones that vary greatly in fraction of afforested area. Beech dominates in all zones and its share increases from the foothills to montane zone (fig. 5). Basing on a digital terrain model, the areal share of 10 landforms was determined for each stand and altitudinal zone (fig. 8). This enabled more detailed planning of species composition. However, it required the adoption of six specific assumptions including the need to maintain a suitable proportion of all tree species growing in the mountains, specifically the main forest tree species: spruce, fir and beech. The 5−stage project (preliminary, historical, current, planning, verification stages) consisting of planning species composition uses, in stage 4, detailed information on landforms. The project assumes that the fragments of forests where trees are expected to grow fast will be earmarked for endangered species. The model sees the need of planting the weaker tree species to be present in the forest ecosystems of the Beskid Niski. The proposed project will enable foresters−practitioners to plan the forest species composition for each of the forest districts in the Beskid Niski quickly. Such a programme might also be an integral part of the growth model of forests useful for forecasting and increasing timber resources.
Źródło:
Sylwan; 2016, 160, 03; 219-229
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
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:
Zmiany zachodzące w lasach Ziemi Kłodzkiej w latach 2001-2017
Changes in the forests of the Kłodzko Region in years 2001-2017
Autorzy:
Dmyterko, E.
Bruchwald, A.
Powiązania:
https://bibliotekanauki.pl/articles/985721.pdf
Data publikacji:
2019
Wydawca:
Polskie Towarzystwo Leśne
Tematy:
lesnictwo
Ziemia Klodzka
lasy
sklad gatunkowy
zmiany skladu gatunkowego
klasy wieku
struktura drzewostanu
pozyskiwanie drewna
zlomy
wykroty
posusz
miazszosc surowca drzewnego
zmiany w drzewostanach
dynamika zmian
zagrozenia drzewostanow
lata 2001-2017
species composition
stand age structure
timber harvest
damage caused by wind and drought
stand
growth model
Opis:
The aim of the study was to assess the changes occurring in the forests of the Kłodzko Region in the recent period (2001−2017), with particular emphasis on the species composition of the stands, their share in age classes and the structure of harvested timber, including live trees, deadwood, wind−broken and wind−fallen trees. The Kłodzko Region located in the Sudety Mountains (SW Poland) covers the forests of four forest districts: Lądek−Zdrój, Międzylesie, Bystrzyca Kłodzka and Zdroje. The declining share of spruce stands (from 83.5% in 2001 to 75.5% in 2017) and the increasing share of beech and larch as well as sycamore stands indicate that these forests are systematically rebuilt. The average age of the stands is very high (81 years). The share of young (<20 years old ) stands is low (only 5%), while those older than 100 years constitute about 35%. The 21st century saw a serious damage to the investigated forests caused by frequent strong winds and long−lasting droughts in the growing seasons. The three hurricanes that took place in the analysed period were the cause of the removal of 1.1 million m3 of timber in the form of wind−broken and wind−fallen trees. The drought in the growing season in 2015 resulted in the salvage harvest of deadwood with a total volume of 1.6 million m3, which corresponds to the volume of four annual allowable cuts determined for the undisturbed growth conditions of trees in the area under research. Using the wind damage risk model, the threat measure Ms reaching a value of above 40 was calculated for the forests of the Kłodzko Region, which are currently among the most threatened in Poland. This threat results mainly from the high share of spruce stands in older age classes with high average height and gaps after previous hurricanes as well as from a large area of stands located at high elevations.
Źródło:
Sylwan; 2019, 163, 08; 675-684
0039-7660
Pojawia się w:
Sylwan
Dostawca treści:
Biblioteka Nauki
Artykuł
    Wyświetlanie 1-5 z 5

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