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Wyświetlanie 1-6 z 6
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:
Metoda inwentaryzacji lasu oparta na losowaniu warstwowym wykorzystująca model wzrostu drzewostanu
Forest inventory method based on stratified sampling using a stand growth model
Autorzy:
Bruchwald, Arkadiusz
Dmyterko, Elżbieta
Mionskowski, Marcin
Powiązania:
https://bibliotekanauki.pl/articles/18055687.pdf
Data publikacji:
2023
Wydawca:
Instytut Badawczy Leśnictwa
Tematy:
miąższość drzewostanu
próba
ryzyko uszkodzenia
model wzrostu drzewostanu
stand volume
sample
damage risk
stand growth model
Opis:
The paper presents a new variant of the method for determining the stand volume of age classes in a forest district or inspectorate (subdistrict). The methodological basis for this variant of the method is a branch of mathematical statistics called the "representative method", which is based on stratified sampling, similar to the variant of forest inventory currently used in forestry. In the new variant of the method, strata are formed based on the age of the main tree species and the stand volume, which is determined by the stand growth model, while in the variant currently used, strata are formed based on the stand's main tree species and its age. In the new variant of the stand volume determination method, 13 stages are distinguished, which can be divided into the initial and the main part. First, data from the State Forest Information System (SILP) database are processed: the age of the stand's main tree species and characteristics that allow to determine the volume of each stand of the forest district or inspectorate using a stand growth model. Based on the age and stand volume, strata for the forest district or inspectorate can be formed and the number of samples for each of these strata can be determined. The main part of the new variant of the method starts with the measurement of DBH and tree height on the sample plots. The results of these measurements are then processed using, for example, a stand growth model. The volume of individual strata, age classes, and the entire forest district is determined. When using a growth model, many other stand characteristics are also determined, including volume increment, degree of windthrow hazard, rotation, and 10-year size of final and intermediate fellings. The evaluation of the accuracy of the method was based on data from 73 forest inspectorates in Poland. This was preceded by studies on the dispersion measures of the sum of tree volume on sample plots of different sizes. The new variant of the forest inventory method proved to be about 30% more accurate than the previously used variant.
Źródło:
Leśne Prace Badawcze; 2023, 83; 25-32
1732-9442
2082-8926
Pojawia się w:
Leśne Prace Badawcze
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 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:
Model wzrostu modrzewia europejskiego (Larix decidua Mill.)
Growth model for European larch [Larix decidua Mill.]
Autorzy:
Bruchwald, A.
Zasada, M.
Powiązania:
https://bibliotekanauki.pl/articles/1009318.pdf
Data publikacji:
2010
Wydawca:
Polskie Towarzystwo Leśne
Tematy:
lesnictwo
dendrometria
drzewa lesne
modrzew europejski
Larix decidua
modele wzrostu
modele stochastyczne
drzewostany modrzewiowe
struktura drzewostanu
produkcyjnosc lasu
growth and yield model
european larch
forest productivity
stand structure
Opis:
The paper discusses the functioning scheme and components of the stochastic growth model for European larch. The model was presented in the form suitable for processing the periodic forest inventory data (diameter and height of trees measured on fixed sample plots and average stand age). The growth model for larch consists of four main algorithms: introductory, thinning, mortality and incremental. First, the introductory algorithm is run to determine stand characteristics at certain age. Next, the thinning algorithm linked with the mortality procedure is activated. In the next step, incremental algorithm (also coupled with mortality program) is turned on. Thinning and incremental programs are run alternately until the end of prognosis period is reached. One of the most important characteristics of forest stand structure is tree stocking utilized directly by the thinning algorithm. The presented model is suitable for prognosis of European larch stands with any age, site index, stocking and various results of measured diameters and heights. It requires verification based on independent empirical data, preferably from permanent research plots.
Źródło:
Sylwan; 2010, 154, 09; 615-624
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
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