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Tytuł:
Ensemble of feature extraction methods to improve the structural damage classification in a wind turbine foundation
Autorzy:
Leon-Medina, Jersson X.
Parés, Núria
Anaya, Maribel
Tibaduiza, Diego A.
Pozo, Francesc
Powiązania:
https://bibliotekanauki.pl/articles/27311417.pdf
Data publikacji:
2023
Wydawca:
Polska Akademia Nauk. Czasopisma i Monografie PAN
Tematy:
structural health monitoring
wind turbine foundation
damage classification
machine learning
feature extraction
XGBoost
monitorowanie stanu konstrukcji
fundament turbiny wiatrowej
klasyfikacja uszkodzeń
uczenie maszynowe
ekstrakcja cech
Opis:
The condition monitoring of offshore wind power plants is an important topic that remains open. This monitoring aims to lower the maintenance cost of these plants. One of the main components of the wind power plant is the wind turbine foundation. This study describes a data-driven structural damage classification methodology applied in a wind turbine foundation. A vibration response was captured in the structure using an accelerometer network. After arranging the obtained data, a feature vector of 58 008 features was obtained. An ensemble approach of feature extraction methods was applied to obtain a new set of features. Principal Component Analysis (PCA) and Laplacian eigenmaps were used as dimensionality reduction methods, each one separately. The union of these new features is used to create a reduced feature matrix. The reduced feature matrix is used as input to train an Extreme Gradient Boosting (XGBoost) machine learning-based classification model. Four different damage scenarios were applied in the structure. Therefore, considering the healthy structure, there were 5 classes in total that were correctly classified. Five-fold cross validation is used to obtain a final classification accuracy. As a result, 100% of classification accuracy was obtained after applying the developed damage classification methodology in a wind-turbine offshore jacket-type foundation benchmark structure.
Źródło:
Bulletin of the Polish Academy of Sciences. Technical Sciences; 2023, 71, 3; art. no. e144606
0239-7528
Pojawia się w:
Bulletin of the Polish Academy of Sciences. Technical Sciences
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Katastrofy budowlane powstałe na skutek występowania oddziaływań losowych
Construction disasters caused by random factors
Autorzy:
Szer, Jacek
Szer, Iwona
Powiązania:
https://bibliotekanauki.pl/articles/2202732.pdf
Data publikacji:
2022
Wydawca:
Polski Związek Inżynierów i Techników Budownictwa
Tematy:
katastrofa budowlana
zdarzenie losowe
zmiany klimatyczne
wiatr silny
wybuch gazu
uszkodzenie
element konstrukcji
ranny
ofiara wypadku
construction disaster
random event
climate changes
strong wind
gas explosion
damage
construction element
injured people
casualty
Opis:
W artykule omówiono zagrożenia powstania katastrof obiektów budowlanych, które mogą zaistnieć przy działaniu czynników losowych, takich jak silne i porywiste wiatry, duże opady śniegu, czy wybuchy gazu. Przedstawiona analiza katastrof budowlanych dotyczy okresu 2008-2018, które miały miejsce na terytorium Polski. Zebrane materiały mogą posłużyć identyfikacji obszarów ryzyka w celu oceny powstających zagrożeń i podejmowania skutecznych działań zmniejszające negatywne skutki tych zdarzeń.
The article discussed the risks of catastrophes of building structures, which can occur with random factors such as strong and gusty winds, heavy snowfall, or gas explosions. The presented analysis of construction disasters covered the period 2008-2018, which occurred in Poland. The collected materials can be used to identify areas of risk in order to assess emerging risks and take effective measures to reduce the negative effects of these events.
Źródło:
Przegląd Budowlany; 2022, 93, 9-10; 42--47
0033-2038
Pojawia się w:
Przegląd Budowlany
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Estimation of critical wind speed on the basis of roof blow-off
Oszacowanie krytycznej prędkości wiatru na podstawie zerwanego dachu
Autorzy:
Chmielewski, T.
Kaleta, B.
Nowak, H.
Powiązania:
https://bibliotekanauki.pl/articles/230821.pdf
Data publikacji:
2020
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
burza wiatrowa
derecho
uszkodzenie budynku
zdmuchnięcie dachu
współczynnik aerodynamiczny
prędkość krytyczna
prędkość wiatru
wind storm
building damage
roof blow-off
aerodynamic coefficient
critical speed
wind speed
Opis:
W dniach 11-12 sierpnia 2017 r. nad Polską przeszła rozległa burza wiatrowa. Cała burza obejmowała obszar około 540 km od Wrocławia, przez Poznań, Bydgoszcz, wzdłuż Gdyni i Gdańska oraz część Wybrzeża. Z dużą siłą wiatru przeszła przez trzy województwa: Wielkopolskie, Kujawsko-Pomorskie i Pomorskie. Pomierzone prędkości wiatru osiągnęły 130 km/h, powodując duże zniszczenia na swojej drodze, a w jednej stacji synoptycznej, tj. w Elblągu prędkość wiatru przekroczyła 150 km/h. Maksymalne prędkości wiatru zostały pomierzone w następujących miejscowościach: Chojnice: 31.2 m/s (112 km/h), Gniezno: 34.8 m/s (125 km/h), Chrząstowo/Noteć: 36.0 m/s (130 km/h), Elbląg: 42,0 m/s (151 km/h). Ścieżka przejścia burzy była w przybliżeniu liną prostą, miała ponad 400 km długości i w trzech miejscach oddalonych około 70 km wiatr wiał z prędkością 100 km/, czyli burza spełniała kryteria burzy „derecho”. Burza wiatrowa spowodowała ofiary ludzkie i ogromne straty materialne opisane w pracy [8]. Celem artykułu jest oszacowanie krytycznej prędkości wiatru w zdarzeniu zerwania dachu jednopiętrowego ceglanego budynku podczas burzy wiatrowej w dniu 11 sierpnia 2017 r. W tym celu obliczono ciężar konstrukcji i pokrycia dachu oraz oszacowano siłę połączenia między murłatami i ściankami kolankowymi. Wzajemne porównanie obu tych sił umożliwiło obliczenie krytycznej prędkości wiatru, która okazała się znacznie większa od wartości pomierzonych na stacjach meteorologicznych.
Types of wind storms in Poland and examples of economic damage, threats to human life and health caused by two extreme wind events are presented. Then, a house with the roof blown-off during the derecho wind storm in Poland on August 11-12, 2017, is considered. Based on the rafter framing of the house, i.e. wooden roof structure elements and roof covered, the weight of the roof is calculated. Two cases of the strong connection between rafter plates and knee walls are estimated. With the estimation of connection strength between rafter plates and knee walls, it was possible to calculate the total force required to blow-off the roof of the house. Next, an aerodynamic force acting on the house is calculated using pressure coefficients for a low-rise house with a gable roof. The pressure coefficients were taken from the Tokyo Polytechnic University aerodynamic database. The aerodynamic force acting on the roof blown-off was calculated for a low-rise building with a gable roof for similar ratios for length, width, and height. Three wind directions, for the unknown orientation of the building, were considered, i.e. the wind direction perpendicular, parallel, and oblique to the gable wall. By comparison, the aerodynamic force with the total force required to blow-off the roof of the house, it was possible to calculate the critical wind speed needed for the roof blown-off. This wind speed is much bigger than measured by meteorological stations on the path of the derecho.
Źródło:
Archives of Civil Engineering; 2020, 66, 3; 391-405
1230-2945
Pojawia się w:
Archives of Civil Engineering
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Ocena szkód w lasach Polski spowodowanych przez huragan w sierpniu 2017 roku
Assessment of the damage to Polish forests caused by a hurricane in August 2017
Autorzy:
Dmyterko, E.
Bruchwald, A.
Powiązania:
https://bibliotekanauki.pl/articles/978974.pdf
Data publikacji:
2020
Wydawca:
Polskie Towarzystwo Leśne
Tematy:
wind−caused damage
risk model
stand growth model
allowable cut
Opis:
On August 11−12, 2017, a hurricane passed from south to north of Poland causing considerable damage to forests, especially in regional directorates of the State Forests in Wrocław, Poznań, Toruń, Szczecinek and Gdańsk. By the end of 2018, the volume of wind−broken and wind−fallen trees and deadwood approximated to 9 million m3. In 9 forest districts the harvested volume exceeded 440 thousand m3, including two entities with over 1 million m3 each. The harvested volume was expressed as a percentage of allowable cut, calculated from the stand growth model. It showed possibile timber harvest in final and intermediate cuts in the absence of natural disasters (strong wind, intense drought, heavy snowfall, insect outbreaks, etc.). In many forest districts, timber harvest accounted for 100% of the allowable cut, with the maximum value approximated to 1100% of the allowable cut. The high salvage harvest of post−hurricane timber prevents the execution of other economic tasks, including plans of stand rebuilding. On the example of forest districts with the largest damage, the possibilities of selecting forests classified as the most threatened by wind were examined. The wind damage risk model for the stand was used to determine the value of wind damage risk factor Wr for each stand (values from 0 to 3; the higher value, the higher risk). The damage risk factor allowed to create six damage risk classes of a span of 0.5 each and to assign individual stands to one of the damage classes. The share of the area of stands and damaged stands in Wr classes was also determined. In the Lipusz Forest District the share of stands in VI class of Wr was 9.8%, and the area of damaged stands in this class was 98.3%. In the Rytel and Przymuszewo forest districts, the areal share of such stands was 10.7% and 5.1%, respectively, and almost all stands in this class were damaged by the hurricane. The areal share of forests in the highest Wr class was reported in the Gniezno Forest District accounting for 4.8% and the hurricane damaged 85% of their area. The wind damage risk model for the stand allows to identify forests where damage is very likely to occur. It is, therefore, possible to take action on the rebuilding of stands before the wind comes and thus reduce its negative effects. The cutting plan should include, in the first place, stands classified to the high wind damage risk factor.
Źródło:
Sylwan; 2020, 164, 05; 355-364
0039-7660
Pojawia się w:
Sylwan
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Dynamika procesu zamierania drzew w Sudetach w latach 2002-2018
Dynamics of tree mortality in the Sudety Mts. in years 2002-2018
Autorzy:
Bruchwald, A.
Dmyterko, E.
Mionskowski, M.
Wrzesiński, P.
Powiązania:
https://bibliotekanauki.pl/articles/985747.pdf
Data publikacji:
2019
Wydawca:
Polskie Towarzystwo Leśne
Tematy:
lesnictwo
Sudety
drzewa lesne
zamieranie drzew
zlomy
wywroty
drewno pokleskowe
posusz
lata 2002-2018
gatunki lasotworcze
swierk
modrzew
buk
jodla
daglezja
przyrosty radialne
wiek drzew
damage caused by drought and wind
volume of deadwood
wind−broken and wind−fallen trees
radial growth
Opis:
The aim of the study was to present two issues concerning forests in the Sudety Mts. (SW Poland): 1) the process of tree mortality in individual years in the period between 2002 and 2018, as well as 2) the analysis of the radial growth of the main tree species (i.e. spruce, larch, beech, fir and Douglas fir). The intensity of the process of tree mortality is evidenced by the volume of wind−broken or wind−fallen trees and deadwood. The record volume of post−hurricane wood was harvested after the hurricane ‘Cyril’ (January 2007). The volume of wood removed in 2007−2008 amounted to 1.4 million m3. Quite a high share of wind−broken and wind−fallen trees in the volume of harvested wood raw material concerned the years 2002, 2003, 2006, 2008 and 2018. In the latter year, the damage was caused by the hurricane ‘Grzegorz’. The record removal of deadwood occurred in 2016 following an exceptionally severe drought in the 2015 growing season. The high volume of deadwood in 2017 and 2018 was augmented by quite a high volume of wind−broken and wind−fallen trees. Spruce and larch showed the strongest response to severe drought in 2015 by lowering the increment in diameter and producing a narrow layer of latewood, while the response of beech and Douglas fir was the slightest. No such response was found in fir. The main tree species in the Sudetes is spruce, which quickly disappears from this area. It is necessary to look for such species of trees that might replace spruce, i.e. species more suitable to changing climatic conditions, such as beech, oak, ash, sycamore, pine and larch – but also fir and Douglas fir. The latter two species show a high tolerance to changing climatic conditions, and a high potential in the production of wood.
Źródło:
Sylwan; 2019, 163, 12; 969-979
0039-7660
Pojawia się w:
Sylwan
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Rare weather phenomena and the work of large-format roof coverings
Autorzy:
Ksit, Barbara
Szymczak-Graczyk, Anna
Powiązania:
https://bibliotekanauki.pl/articles/971031.pdf
Data publikacji:
2019
Wydawca:
Uniwersytet Zielonogórski. Oficyna Wydawnicza
Tematy:
wind load
hurricane wind
roof covering
damage
membrane
sail effect
obciążenie wiatrem
huragan
pokrycie dachu
uszkodzenia
membrana
efekt żagla
Opis:
Wind action belongs to loads that are environmentally variable. Wind action is included in the basic combination of loads, whereas hurricane wind action is classified as a unique combination. Due to large gusts of wind, the roof coverings of large-scale buildings are exposed to detachment of their cover layer. The article presents the effects of overnormative wind, which occurred on January 19, 2018 and was named the cyclone Frederic/David. The purpose of the article is to show that in design of roof coverings made of large-format materials, such as membranes, it is crucial to accept wind load values properly in order to ensure a right spacing between fasteners. The presented results might be an important contribution to the debate on the necessity for increasing the fundamental value of the basic wind velocity in the perimeter and corner zones of large-format roofs.
Źródło:
Civil and Environmental Engineering Reports; 2019, 29, 3; 123-133
2080-5187
2450-8594
Pojawia się w:
Civil and Environmental Engineering Reports
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Zastosowanie modelu ryzyka uszkodzenia drzewostanu przez wiatr do oceny prawdopodobieństwa lokalizacji szkód w lasach Regionalnej Dyrekcji Lasów Państwowych w Białymstoku
Application of the wind damage risk model for the assessment of the probability of the location of damage to forests of the Regional Directorate of the State Forests in Bialystok
Autorzy:
Bruchwald, A.
Dmyterko, E.
Powiązania:
https://bibliotekanauki.pl/articles/985727.pdf
Data publikacji:
2019
Wydawca:
Polskie Towarzystwo Leśne
Tematy:
lesnictwo
wiatry
szkody w lesie
drzewostany
ryzyko uszkodzenia
ocena ryzyka
modele ryzyka uszkodzenia
RDLP Bialystok
wind damage risk model
wind damage risk factor
Opis:
In June 2016, a hurricane damaged the forests of the Regional Directorate of the State Forests in Białystok (eastern Poland), resulting in the removal of approximately 1.9 million cubic meters of wind−fallen and wind−broken trees and deadwood by the end of 2018. The research material was obtained from the database of the State Forests Information System and used to assess the functioning of the wind damage risk model. The wind damage risk model determines the value of damage risk factor Wr for each stand ranging from 0 to 3; a higher value indicates a higher risk of damage to the stand. The damage risk factor allowed to create six damage risk classes, with a width of 0.5 each and to assign individual stands of the forest district to one of the classes. The areal share of damaged stands was calculated for each class. In 2015, i.e. before the hurricane, the share of stands in the highest damage risk class VI ranged from 0.1% to 3.5%. After the hurricane in 2016, the areal share of damaged stands was calculated for each class, the largest share (the largest damage) being in class VI, while the share of the most damaged stands were found in the following forest districts: Dojlidy – 71%, Supraśl – 79% and Żednia – 87%. In 9 other forest districts, the area of damaged stands in class VI also exceeded 70%. The wind damage risk model for the stand presented in the paper allows identifying stands where damage is very likely to occur, when the wind comes. This may limit the level of wind damage through, in the first place, the rebuilding of stands classified to the highest wind damage risk factor class.
Źródło:
Sylwan; 2019, 163, 08; 629-636
0039-7660
Pojawia się w:
Sylwan
Dostawca treści:
Biblioteka Nauki
Artykuł
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 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
Tytuł:
Dynamika rozpadu drzewostanów świerkowych w Beskidzie Śląskim
Decline of Norway spruce stands in the Beskid Slaski Mts.
Autorzy:
Dmyterko, E.
Bruchwald, A.
Powiązania:
https://bibliotekanauki.pl/articles/986624.pdf
Data publikacji:
2018
Wydawca:
Polskie Towarzystwo Leśne
Tematy:
lesnictwo
Beskid Slaski
drzewostany swierkowe
zamieranie drzew
swierk pospolity
Picea abies
rozpad drzewostanow
System Informatyczny Lasow Panstwowych
model wzrostu drzewostanu
rozmiar uzytkowania rebnego
zagrozenia lasu
szkody od wiatru
modele ryzyka uszkodzenia
Nadlesnictwo Wisla
Nadlesnictwo Wegierska Gorka
Nadlesnictwo Ustron
Nadlesnictwo Bielsko
forest decline
picea abies
stand growth model
harvest volume model
wind damage risk model
forest
threat measure
Opis:
The dynamics of decline of Norway spruce forests in the Beskid Śląski Mts. (S Poland) in a 2007−2016 period was analysed based on data from the State Forests Information System. For that purpose we used modified growth model and wind damage risk model. The harvested timber volume (salvage cuts) exceeded the allowable harvest modeled with the stand growth model by 270% in years 2007−2010 (earlier period) and by 89% in the 2011−2016 (later period) period. The highest volume exceed (503 and 307% for earlier and later period respectively) was recorded for the Wisła Forest District. For the deadwood, the harvested volume exceeded the modeled one by 45% (162 in earlier, and 59% in later period). In the Węgierska Górka Forest District the harvested volume amounted to 287% of the modeled one (438 in earlier, and 70% in later period). The largest amount of wind−broken and wind−fallen trees was found in Wisła. Their volume amounted to 48% of the modeled volume (59 in earlier, and 40% in later period). The highest exceed occurred in Węgierska Górka (89 and 70% in the later period respectively). The species composition in the analysed region changed significantly as the share of spruce decreased and share of beech and fir increased (tab. 1). Changes in the aeral fraction of stands in age classes in the Bielsko and Ustroń forest districts were insignificant (tab. 2). For Węgierska Górka, share of stands in age class <20 years increased from 11 to 40%, while the older stands fraction decreased. Major changes occurred in Węgierska Górka and Wisła as far as structure of the stands in the risk damage factor classes is concerned. Fraction for the risk factor classes I and II increased, while for class VI decreased (tab. 3, fig. 4). The highest dynamics of the wind threat measure was recorded especially in Węgierska Górka, where its value decreased from 42 in 2009 to 19 in 2016 (fig. 5). The biggest changes are likely to occur in Wisła in the next years due to the very high fraction of spruce. A significant damage caused by wind may also be expected in Ustroń, where the threat measure is high.
Źródło:
Sylwan; 2018, 162, 03; 189-199
0039-7660
Pojawia się w:
Sylwan
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Warunki meteorologiczne powstania szkód wiatrowych w dniach 11-12 sierpnia 2017 roku w lasach środkowo-zachodniej Polski
Meteorological conditions of the occurrence of wind damage on August 11-12, 2017 in the forests of central-western Poland
Autorzy:
Chojnacka-Ożga, L.
Ożga, W.
Powiązania:
https://bibliotekanauki.pl/articles/986621.pdf
Data publikacji:
2018
Wydawca:
Polskie Towarzystwo Leśne
Tematy:
lesnictwo
lasy
szkody w lesie
szkody od wiatru
warunki meteorologiczne
wiatry
Polska Srodkowo-Zachodnia
mesoscale convective system
wind gust
forest damage
Opis:
Climate change, which was particularly marked at the turn of the 20th and 21st centuries, was accompanied by unfavourable weather phenomena. One of whose effects cannot be prevented is hurricane. Much of the most devastating storms (e.g. Kyrill in January 2007, Carmen in November 2010), which crossed over Poland, was associated with low pressure systems. The occurrence of high wind speeds in the cold season is a natural feature of Polish climate. Hurricanes in the summer are generally characterized by more complicated origin. The cause of the damage at this time of year may be squall fronts and tornados (e.g. July 4th, 2002 – Puszcza Piska; July 20th, 2007 – Częstochowa region). An important issue is to develop a category of winds for the forest district, which can have destructive effect on the stands. Current research shows that gusty winds exceeding 11 m/s may cause first damage to the trees, while blows with velocity exceeding 30 m/s result in severe damage. Knowing and monitoring the mechanisms that leads to strong winds, assessing their impact, and managing risk in the context of their effects is one of the important elements of a forest management strategy. On August 11th, 2017, after the influx of hot tropic air, much cooler polar air began to flow from the west. In the afternoon and evening storm cell and supercell began to form in the south−west of the country. Later on, they moved in the north direction forming a squall line. With a Mesoscale Convective System (MCS) moving to the north, there was a gusty wind exceeding 40 m/s in some places. A gust of wind occurred around 18.30 (EET) in Dolny Śląsk (SW Poland) and after about 2 hours in Pomerania (N Poland). The pressure tendency during the transition reached 4−5 hPa. In the northern part of the country, gusts of wind were the largest and occurred several times in 2−3 hours. The system was accompanied by heavy precipitations, which in north Poland determine more than 60% of the average monthly rainfall. The effect of moving MCS was the damage of almost 80 thousand hectares of forests in Poland, which of more than 39 thousand hectares were classified to complete restoration.
Źródło:
Sylwan; 2018, 162, 03; 200-208
0039-7660
Pojawia się w:
Sylwan
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Wpływ postępowania ochronnego na występowanie kornika drukarza Ips typographus (L.) w Dolinie Kościeliskiej w Tatrzańskim Parku Narodowym
Effect of forest protection strategy on the occurrence of the spruce bark beetle Ips typographus (L.) in the Koscieliska Valley in the Tatra National Park
Autorzy:
Grodzki, W.
Gąsienica Fronek, W.
Powiązania:
https://bibliotekanauki.pl/articles/986615.pdf
Data publikacji:
2018
Wydawca:
Polskie Towarzystwo Leśne
Tematy:
lesnictwo
Tatrzanski Park Narodowy
Dolina Koscieliska
obszary ochrony scislej
drzewostany swierkowe
drzewostany uszkodzone
wiatrolomy
szkodniki roslin
kornik drukarz
Ips typographus
wystepowanie
bark beetles
norway spruce
wind damage
outbreaks
nature conservation
Opis:
In the end of 2013 the Norway spruce stands in the Kościelska Valley in the Tatra National Park (S Poland) were severely damaged by the wind. In the next year about 22,000 m3 of timber from broken and fallen trees was processed and removed from the active protection zone, whilst in the strict protection zone those trees were left. In 2014, when the presented survey started, the infestation of lying and surrounding standing trees was very low, but starting from 2015 an intensive bark beetle Ips typographus outbreak affected the survived stands. No−intervention strategy was implemented by the national park in both zones, regardless their formal status at that time as well. In 2015 a set of 10 observation plots (200 trees in total) was established in both active and passive (strict) protection zones (5 plots in each zone). In 2017 a new set of 12 plots (240 trees in total) was installed (6 plots in each zone). On each plot the breast height diameter of all trees was measured and the relative mortality of trees (share of attacked spruces) was recorded each year. The infestation density and sex ratio were defined on the 25×25 cm bark samples taken from 138 trees in 2 trunk sections located 1.5−2.0 above the ground and in the midway between tree and crown bases. The bark beetle attack on living spruces in 2015 differed between the active and strict protection zones. The relative tree mortality was lower in active than in passive protection zone (20 and 39% respectively), but later it gradually came to be similar in both parts of the area (73.3 and 77.5%, respectively in 2017). In the initial outbreak phase, thinner (weaker) trees were attacked, and in the following years – stronger ones, although in the active protection zone the opposite pattern occurred initially. The attack density decreased in subsequent years, being higher in active protection zone, with gradually decreasing difference between zones. Thicker trees were attacked with lower intensity. The share of females, higher in active protection zone (68.2 vs. 63.9%), gradually decreased to (57.9 vs. 51.2%). The initial decrease of bark beetle attack intensity in the active protection zone gradually disappeared after the no−intervention strategy was applied. The resulting extended bark beetle infestation and its increasing intensity in both parts of the area, demonstrate the appropriateness and effectiveness of active protection measures applied in 2014.
Źródło:
Sylwan; 2018, 162, 08; 628-637
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:
The Problem of Airflow Around Building Clusters in Different Configurations
Autorzy:
Jędrzejewski, M.
Poćwierz, M.
Zielonko-Jung, K.
Powiązania:
https://bibliotekanauki.pl/articles/139849.pdf
Data publikacji:
2017
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
environmental wind engineering
airflow around buildings
damage mechanics
CFD simulation
k-ε realizable model of turbulence
RSM model of turbulence
inżynieria wiatrowa
przepływ powietrza wokół budynków
mechanika uszkodzeń
symulacja obliczeniowej dynamiki płynów CFD
model turbulencji k-ε realizable
model turbulencji RSM
Opis:
In the paper, the authors discuss the construction of a model of an exemplary urban layout. Numerical simulation has been performed by means of a commercial software Fluent using two different turbulence models: the popular k-ε realizable one, and the Reynolds Stress Model (RSM), which is still being developed. The former is a 2-equations model, while the latter – is a RSM model – that consists of 7 equations. The studies have shown that, in this specific case, a more complex model of turbulence is not necessary. The results obtained with this model are not more accurate than the ones obtained using the RKE model. The model, scale 1:400, was tested in a wind tunnel. The pressure measurement near buildings, oil visualization and scour technique were undertaken and described accordingly. Measurements gave the quantitative and qualitative information describing the nature of the flow. Finally, the data were compared with the results of the experiments performed. The pressure coefficients resulting from the experiment were compared with the coefficients obtained from the numerical simulation. At the same time velocity maps and streamlines obtained from the calculations were combined with the results of the oil visualisation and scour technique.
Źródło:
Archive of Mechanical Engineering; 2017, LXIV, 3; 401-418
0004-0738
Pojawia się w:
Archive of Mechanical Engineering
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Aktywność enzymatyczna gleb na obszarach sztucznej i naturalnej regeneracji lasu po klęsce huraganu w północno-wschodniej Polsce
Soil enzymatic activity in artificially and naturally regenerated forests after wind damage in north-eastern Poland
Autorzy:
Olszowska, G.
Powiązania:
https://bibliotekanauki.pl/articles/1294052.pdf
Data publikacji:
2016
Wydawca:
Instytut Badawczy Leśnictwa
Tematy:
lesnictwo
tereny pohuraganowe
drzewostany sosnowe
gleby lesne
ureaza
dehydrogenazy
aktywnosc enzymatyczna
wind damage
urease
dehydrogenases
forest soils
Opis:
The aim of the study was to describe biochemical reactions in the soil based on the activity of urease and dehydrogenases in Scots pine stands damaged during and differentially managed after hurricanes. Soil enzymatic activity was investigated in 2005 and again in 2013 for selected stands in the Pisz Forest District where wind damage occurred in 2002. Most of the damaged stands were cut down and replanted, but 445 ha were left untouched for study purposes. The investigated areas differed with respect to stand damage and management. The enzymatic activity correlated well with the content of organic matter which was higher in organic than in mineral soils. In the area left to regenerate naturally, dehydrogenase and urease activity was higher in 2013 compared to 2005, which suggests the improvement of site conditions. The values of the examined biochemical parameters were correlated with the type of forest regeneration, with the forest soil regeneration being higher in artificially than in naturally regenerated stands. Changes of soil enzymatic activity were correlated with the level of stand damage and the type of management after wind damage.
Źródło:
Leśne Prace Badawcze; 2016, 77, 2
1732-9442
2082-8926
Pojawia się w:
Leśne Prace Badawcze
Dostawca treści:
Biblioteka Nauki
Artykuł
Wyświetlanie 1-15 z 27

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