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Wyszukujesz frazę "tree mortality" wg kryterium: Temat


Wyświetlanie 1-5 z 5
Tytuł:
Growth response of different tree species (oaks, beech and pine) from SE Europe to precipitation over time
Autorzy:
Stojanović, Dejan B.
Levanič, Tom
Matović, Bratislav
Stjepanović, Stefan
Orlović, Saša
Powiązania:
https://bibliotekanauki.pl/articles/956967.pdf
Data publikacji:
2018
Wydawca:
Polska Akademia Nauk. Instytut Dendrologii PAN
Tematy:
standardized precipitation index (spi)
climate change
tree mortality
quercus sp.
fagus sylvatica
pinus sylvestris
Opis:
Changing climatic conditions can have various consequences for forest ecosystems, from increasing frequencies of forest fires, ice and windstorm events to pathogen outbreaks and mass mortalities. The Standardized Precipitation Index (SPI) was chosen for the evaluation of drought impact on the radial growth of trees after extensive preliminary testing of various calculated monthly climate parameters from the CARPATCLIM database. SPI was calculated for periods between 3 and 36 months for different sites (lowland and mountainous parts of Serbia, Southeast Europe), from which Quercus robur, Q. cerris, Fagus sylvatica and Pinus sylvestris samples were acquired. Bootstrapped Pearson’s correlations between SPI monthly indices and radial growth of tree species were calculated. We found that 12-month SPI for summer months may be a good predictor of positive and negative growth of different species at different sites. The strongest positive correlations for five of six tree-ring width chronologies were between 12-month June and 14-month September SPI, which implies that high growth rates can be expected when the autumn of the previous year, and winter, spring and summer of the current year, are well supplied with precipitation, and vice versa (low precipitation in given period/low growth rates).
Źródło:
Dendrobiology; 2018, 79; 97-110
1641-1307
Pojawia się w:
Dendrobiology
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:
Flowering of Picea abies (L.) Karst. clones of Istebna origin in the Kórnik seed orchard
Autorzy:
Chalupka, W
Rozkowski, R.
Powiązania:
https://bibliotekanauki.pl/articles/41272.pdf
Data publikacji:
2004
Wydawca:
Polska Akademia Nauk. Instytut Dendrologii PAN
Tematy:
Norway spruce
Picea abies
clone
flowering
graft mortality
genetic variation
seed orchard
forest tree species
Opis:
The flowering and graft mortality of Norway spruce clones of Istebna origin was only slightly different from clones of other origin in the same seed orchard. The negative effect ofmoving Istebna clones from the south to the north of their origin was probably compensated by moving them from a higher altitude to lowland. There is a danger that the complete loss of several clones, observed in the seed orchard with time,may really decrease the expected level of genetic variation in the progeny. It is recommended that the mortality of grafts and the reduction in the number of clones in the seed orchard should be under permanent observation.
Źródło:
Dendrobiology; 2004, 51 Supplement
1641-1307
Pojawia się w:
Dendrobiology
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Mortality, recruitment, and increment of trees in the Fagus-Abies-Picea stands of a primeval character in the lower mountain zone
Autorzy:
Jaworski, A
Kolodziej, Z.
Lapka, M.
Powiązania:
https://bibliotekanauki.pl/articles/41489.pdf
Data publikacji:
2007
Wydawca:
Polska Akademia Nauk. Instytut Dendrologii PAN
Tematy:
Dentario glandulosae-Fagetum association
forest
Abies alba
Fagus sylvatica
development stage
developmental phase
tree
mortality
recruitment
increment
lower mountain zone
Opis:
From among three stands, situated in the lower mountain zone, and representing the association Dentario-glandulosae Fagetum, the Łopuszna I stand, being in the growing up stage and phase of selection forest, reached the highest increment (8.5 m3/ha/year, i.e. 1.3% of actual stand volume/ha measured at the end of the control period). Stands, Łopuszna II, being in the stage of an intensive break-up, and Łopuszna III, being in the stage of an initial break-up, reached smaller increments (5.4 and 6.3 m3/ha/year respectively, i.e. each 0.9% of actual stand volume/ha). The greatest tree mortality occurred in stands Łopuszna II and III (14.1 and 10.5 m3/ha/year respectively), and the smallest in the stand Łopuszna I (4.8 m3/ha/year). The knowledge about the value of mortality, recruitment, and increment, expressed in the number of trees and in volume units, may greatly help in planning the amount of cut which would secure sustainability of the forest ecosystem in the layer of trees in the economic as well as in the protection forests, under similar stand and site conditions, managed by the selection cutting permitting to realize the conception of a close-to-nature silviculture.
Źródło:
Dendrobiology; 2007, 57; 15-26
1641-1307
Pojawia się w:
Dendrobiology
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Prediction of mortality rates in heart failure patients with data mining methods
Autorzy:
Bohacik, J.
Kambhampati, C.
Davis, D. N.
Cleland, J. G. F.
Powiązania:
https://bibliotekanauki.pl/articles/908867.pdf
Data publikacji:
2013
Wydawca:
Uniwersytet Marii Curie-Skłodowskiej. Wydawnictwo Uniwersytetu Marii Curie-Skłodowskiej
Tematy:
heart failure
data mining
prediction of mortality rates
home telemonitoring
Bayesian network method
decision tree method
neural network method
nearest neighbour method
Opis:
Heart failure is one of the severe diseases which menace the human health and affect millions of people. Half of all patients diagnosed with heart failure die within four years. For the purpose of avoiding life-threatening situations and minimizing the costs, it is important to predict mortality rates of heart failure patients. As part of a HEIF-5 project, a data mining study was conducted aiming specifically at extracting new knowledge from a group of patients suffering from heart failure and using it for prediction of mortality rates. The methodology of knowledge discovery in databases is analyzed within the framework of home telemonitoring. Several data mining methods such as a Bayesian network method, a decision tree method, a neural network method and a nearest neighbour method are employed. The accuracy for the data mining methods from the point of view of avoiding life-threatening situations and minimizing the costs is discussed. It seems that the decision tree method achieves the best accuracy results and is also interpretable for the clinicians.
Źródło:
Annales Universitatis Mariae Curie-Skłodowska. Sectio AI, Informatica; 2013, 13, 1; 7-16
1732-1360
2083-3628
Pojawia się w:
Annales Universitatis Mariae Curie-Skłodowska. Sectio AI, Informatica
Dostawca treści:
Biblioteka Nauki
Artykuł
    Wyświetlanie 1-5 z 5

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