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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 modeli ryzyka uszkodzenia drzewostanu przez wiatr do oceny zagrożenia lasów nadleśnictwa
Application of wind damage risk models for the assessment of danger to stands within a forest district
Autorzy:
Bruchwald, A.
Dmyterko, E.
Powiązania:
https://bibliotekanauki.pl/articles/974051.pdf
Data publikacji:
2011
Wydawca:
Polskie Towarzystwo Leśne
Tematy:
wiatry
szkody w lesie
drzewostany
ryzyko uszkodzenia
modele ryzyka uszkodzenia
leśnictwo
zagrożenia lasu
ocena zagrożenia
nadleśnictwa
RDLP Kraków
wind damage
risk models
wind damage risk indices
Opis:
The study presents a risk model for stand damage caused by wind. It is associated with the following groups of factors: the variable characteristics of stand, its permanent characteristics, the position of a forest district in the region of the country, the damage that occurred in the stand in the past. The model generates a risk factor for tree damage ranging from 0 to 3. The higher value it indicates, the higher risk for the stand. The model serves for the assessment of risks to stands in the Cracow Regional Directorate of the State Forests.
Źródło:
Sylwan; 2011, 155, 07; 459-471
0039-7660
Pojawia się w:
Sylwan
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Comparative study between Poland and South Africa wind climates, the related damage and implications of adopting the eurocode for wind action on buildings
Autorzy:
Goliger, A.
Żurański, J.
Giżejowski, M.
Gaczek, M.
Retief, J.
Kruger, A.
Dunaiski, P.
Fiszer, S.
Ćwik, M.
Powiązania:
https://bibliotekanauki.pl/articles/231003.pdf
Data publikacji:
2013
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
warunki wiatrowe
szkoda wiatrowa
obciążenie wiatrem
projektowanie konstrukcji
norma
wind climate
wind damage
wind loading
structural design
standard
Opis:
Wind constitutes one of the major environmental factors affecting the design and performance of built environment. Each country has its unique climatic wind conditions, and the way in which these are considered and implemented in the structural design, is important. An implementation or adoption of any new engineering design stipulations introduces a formidable challenge to the developers of the standards and the design profession. This has been experienced in some of the countries (e.g. the UK, Australia and the USA), where processes of modernising the outdated codification took place in the past. Although both Poland and South Africa are currently at the early implementation stage of the new wind loading design stipulations, there is a major difference between the circumstances of the two countries. Poland, as an EU member state, has a compulsory obligation to adopt the new uniform standarisation requirements, within a stipulated time-frame. The South African code developers, after a thorough investigation process which will be highlighted in the paper, decided voluntarily to adopt the Eurocode as the primary model document.
Źródło:
Archives of Civil Engineering; 2013, 59, 1; 51-95
1230-2945
Pojawia się w:
Archives of Civil Engineering
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Zagrożenie lasów Polski na podstawie modelu ryzyka uszkodzenia drzewostanu przez wiatr
Risk of the wind damage to the forests in Poland on the basis of a stand damage risk model
Autorzy:
Dmyterko, E.
Mionskowski, M.
Bruchwald, A.
Powiązania:
https://bibliotekanauki.pl/articles/989828.pdf
Data publikacji:
2015
Wydawca:
Polskie Towarzystwo Leśne
Tematy:
lesnictwo
zagrozenia lasu
wiatry
huragany
uszkodzenia drzewostanow
modele ryzyka uszkodzenia
Polska
wind damage
stand damage risk model
poland
Opis:
On the basis of the wind damage risk model for forests using the data of the State Forests Information System, the stand damage risk factor Wr for each of the 430 forest districts in Poland and the threat measure Ms for a given forest district were determined. The measure of threat to forest Ms for a forest district is a methodical basis for assessing the potential damage to forests in Poland. Its value ranges from 8.1% for the Brzózka Forest District to 48.9% for the Ujsoły Forest District (fig. 1), giving the average value of 24.6% and standard deviation of 7.03%. The measure Ms was the basis for differentiating the levels of threat of wind damage to forest for forest districts. Level 1 (Ms≤10%) indicates low threat, level 2 (10%40%) – very high threat. Low threat to forests was found only in two forest districts located in the western part of the country. 113 forest districts, which form large concentrations particularly in western and central Poland, are exposed to an elevated threat. Most forest districts (233) are classified to a group of moderate threat. They are located across the country and are mostly concentrated in the northern and southern regions of Poland. 71 forest districts exposed to high threat are concentrated in the south of Poland in the Carpathians and the Sudetes, with scattered presence in the north of the country. Most of the 11 forest districts with a very high threat to forests are located in the mountains (tab., fig. 1). For the forest districts with a particularly high and very high threat, new silvicultural procedures and the basis for decision making in the field of forest management should be developed to reduce the risk of damage to forest.
Źródło:
Sylwan; 2015, 159, 05; 361-371
0039-7660
Pojawia się w:
Sylwan
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:
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
Tytuł:
Nowy wariant modelu ryzyka uszkodzenia drzewostanu przez wiatr
New variant of the wind damage risk model for forest stands
Autorzy:
Dmyterko, E.
Bruchwald, A.
Powiązania:
https://bibliotekanauki.pl/articles/991151.pdf
Data publikacji:
2014
Wydawca:
Polskie Towarzystwo Leśne
Tematy:
lesnictwo
wiatry
lasy prywatne
szkody w lesie
drzewostany
uszkodzenia drzewostanow
ryzyko uszkodzenia
obliczenia
modele ryzyka uszkodzenia
wind damage
risk factor
private forests
Opis:
The paper presents a new variant of the wind damage risk model for forest stands in view of its application in the forests under private ownership. It was based on the following characteristics: average height, age and slenderness of the main tree species, stand density index, species composition, forest habitat type, as well as stand location in the region of the country and the volume of windbreaks, windfalls and deadwood in previous years. The latter characteristic in the new model variant is generated by the stand damage model. The new wind damage risk model variant determines the risk factor for individual stands ranging from 0 to 3. A higher value of the factor indicates a higher wind damage risk for the stand. The verification of the model was performed using the forest data from two counties (powiat) situated in the Podkarpackie Province. The wind damage risk factors obtained from the model are shown on numerical maps.
Źródło:
Sylwan; 2014, 158, 08; 571-578
0039-7660
Pojawia się w:
Sylwan
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Analiza zagrożeń wiatrowych powodujących uszkodzenia budynków
Analysis of wind hazard leading to buildings damage
Autorzy:
Gnatowska, R.
Powiązania:
https://bibliotekanauki.pl/articles/357427.pdf
Data publikacji:
2015
Wydawca:
Politechnika Śląska
Tematy:
uszkodzenia wywołane przez wiatr
budynki
silne wiatry
badania w tunelu aerodynamicznym
wind-induced damage
buildings
strong winds
wind tunnel experiments
Opis:
Wzrasta liczba zagrożeń wynikających z oddziaływania silnych wiatrów m.in. w wyniku zwiększenia się gwałtowności zjawisk, obszaru ich występowania, częstości występowania, a także w wyniku niewłaściwej eksploatacji obiektów i ich zużycia naturalnego. Niniejsza praca poświęcona została analizie wpływu oddziaływania silnego wiatru na konstrukcje budynków występujące w różnych konfiguracjach w obszarach zabudowanych. Jej głównym celem było wyznaczenie i przeanalizowanie obciążenia ciśnieniowego obiektów znajdujących się w strefie oddziaływania przepływu. Pomiary zrealizowano w Laboratorium Aerodynamiki Środowiska w Instytucie Maszyn Cieplnych Politechniki Częstochowskiej. Na podstawie analizy wyników wizualizacji oraz aerodynamicznych współczynników ciśnieniowych zaobserwowano, że zmiany charakteru obciążenia wiatrowego zależne są od konfiguracji obiektów.
The increasing number of threats resulting from the impact of strong winds, among others as a result of an increase in the violence of the phenomena of their range, frequency, and as a result of improper operation of facilities and the natural wear and tear. This paper is devoted to the analysis of the impact of the strong wind on the building construction in the different configurations in urban areas. The main aim of the experiment was to determine the pressure distribution on the walls of rectangular objects immersed in flow. Measurements are performed in the Laboratory of Environmental Aerodynamics Institute of Thermal Machinery Czestochowa University of Technology. Based on the results visualization and of aerodynamic ratios pressure observed, that changes the nature of the wind load are dependent on the configuration of objects.
Źródło:
Archiwum Gospodarki Odpadami i Ochrony Środowiska; 2015, 17, 3; 79-90
1733-4381
Pojawia się w:
Archiwum Gospodarki Odpadami i Ochrony Środowiska
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Narx model in rotating machinery diagnostics
Zastosowanie modelu Narx w diagnostyce maszyn wirnikowych
Autorzy:
Bednarz, J.
Barszcz, T.
Uhl, T.
Powiązania:
https://bibliotekanauki.pl/articles/368895.pdf
Data publikacji:
2011
Wydawca:
Akademia Górniczo-Hutnicza im. Stanisława Staszica w Krakowie. Wydawnictwo AGH
Tematy:
model NARX
diagnostyka maszyn wirnikowych
wykrywanie uszkodzeń turbin wiatrowych
NARX model
rotating machinery diagnostics
wind-turbine damage detection
Opis:
Rotating machines are often described using linear methods with acceptable accuracy. Some malfunctions, however, are of non-linear nature. The most common examples of those malfunctions are loose bearings and rotor rubs. Accurate detection and identification of such malfunctions requires more accurate methods. One of such methods can be NARX - nonlinear systems identification. This method is based on neural networks approach and is especially efficient in modeling and diagnostics of nonlinear systems. Application of this method leads to shorter and less costly tuning of the model to the object, which is the key requirement when practical application of a method is concerned. The paper presents how NARX can be applied for modeling of rotating machinery malfunctions. Idea of the diagnostic algorithm based on such modeling is presented. The proposed algorithm was verified during research on a specialized test rig, which can generate vibration signals. The paper also presents results of an application of the NARX method for data collected at a wind turbine.
Maszyny wirnikowe są często opisywane przy użyciu metod liniowych z zadowalającą dokładnością. Niektóre awarie mają jednak charakter nieliniowy; jako przykład można wymienić m.in. takie usterki jak luźne łożyska i przytarcia wirnika. Precyzyjne wykrywanie i identyfikacja ww. usterek wymaga bardziej dokładnych metod. Jedną z takich metod może by NARX - model umożliwiający nieliniową identyfikację systemów. Metoda ta opiera się na sieciach neuronowych i jest szczególnie skuteczna w zakresie modelowania i diagnostyki układów nieliniowych. Zastosowanie tej metody prowadzi do krótszego i mniej kosztownego dostrajania modelu do obiektu, co jest kluczowym wymogiem w przypadku praktycznego zastosowania tej metody w diagnostyce. W artykule przedstawiono, jak modele NARX mogą być stosowane do modelowania awarii maszyn wirnikowych, a także ideę algorytmu diagnostycznego z wykorzystaniem takiego modelowania. Proponowany algorytm został zweryfikowany podczas badań na specjalnym stanowisku badawczym, które umożliwią generowanie sygnałów drganiowych oraz wprowadzanie symulowanych uszkodzeń. W artykule przedstawiono również wyniki zastosowania metody NARX dla danych zarejestrowanych w elektrowni wiatrowej.
Źródło:
Mechanics and Control; 2011, 30, 2; 41-52
2083-6759
2300-7079
Pojawia się w:
Mechanics and Control
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Statystyczna metoda oceny zagęszczenia populacji rytownika pospolitego Pityogenes chalcographus L. na wiatrowałach świerka Picea abies (L.) Karst.
Statistical method for estimating Pityogenes chalcographus L. population density on Norway spruce Picea abies (L.) Karst. windfalls
Autorzy:
Borkowski, A.
Podlaski, R.
Powiązania:
https://bibliotekanauki.pl/articles/995176.pdf
Data publikacji:
2012
Wydawca:
Polskie Towarzystwo Leśne
Tematy:
lesnictwo
drzewostany swierkowe
wiatrowaly
swierk pospolity
Picea abies
szkodniki roslin
rytownik pospolity
Pityogenes chalcographus
wystepowanie
zageszczenie populacji
obliczenia
metody statystyczne
pityogenes chalcographus
picea abies
wind damage
statistical model
Opis:
Pityogenes chalcographus L. (Col., Curculionidae, Scolytinae) is a pest of Norway spruce Picea abies (L.) Karst. characterized by large fluctuations in population size. Despite many publications devoted to P. chalcographus, no accurate method of estimating the population density of this species has been developed. The aim of this study was to develop a statistical method of estimating the total density of P. chalcographus colonising stems and branches of P. abies wind−fallen trees that enables calculation of estimation errors and does not require debarking of whole stems and branches. Linear functions were applied to calculate the total infestation density of stems and branches of P. abies windfalls. The mean relative errors of estimation for stems and branches were smaller than 35% and 45%, respectively.
Źródło:
Sylwan; 2012, 156, 02; 137-146
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:
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:
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:
Stochastyczny model określania miąższości złomów, wywrotów i posuszu
Stochastic model for calculating the volume of wind-broken and wind-thrown wood as well as of deadwood
Autorzy:
Bruchwald, A.
Dmyterko, E.
Powiązania:
https://bibliotekanauki.pl/articles/990021.pdf
Data publikacji:
2014
Wydawca:
Polskie Towarzystwo Leśne
Tematy:
lesnictwo
uszkodzenia drzewostanow
zlomy
wywroty
posusz
miazszosc
modele stochastyczne
damage
risk model
wind
Opis:
The most recent version of the wind damage risk model was published in 2012. The model is based on eleven stand characteristics of which stand damage that occurred in the last decade is among the most important ones. It is expressed as the volume of wood obtained from wind−broken and wind−thrown trees as well as of deadwood. Not taking this feature into consideration would undermine the value of this damage risk factor. In the study, the material contained in the database of the State Forests Information System was used to develop a model for calculating the volume of wood obtained from wind−broken and wind−thrown trees as well as of deadwood. This allowed to apply the stand damage risk model to determine, inter alia, the risk of damage in a multi−variant forecast of timber resources.
Źródło:
Sylwan; 2014, 158, 04; 258-266
0039-7660
Pojawia się w:
Sylwan
Dostawca treści:
Biblioteka Nauki
Artykuł
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