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Wyświetlanie 1-3 z 3
Tytuł:
Rozpad drzewostanów świerkowych w Beskidzie Żywieckim
Dieback of Norway spruce stands in the Beskid Zywiecki Mts.
Autorzy:
Dmyterko, E.
Bruchwald, A.
Mionskowski, M.
Powiązania:
https://bibliotekanauki.pl/articles/979601.pdf
Data publikacji:
2019
Wydawca:
Polskie Towarzystwo Leśne
Tematy:
lesnictwo
Beskid Zywiecki
drzewostany swierkowe
rozpad drzewostanow
swierk pospolity
Picea abies
struktura drzewostanu
struktura wiekowa
struktura gatunkowa
pozyskiwanie drewna
struktura pozyskania
zagrozenia lasu
wiatry
szkody od wiatru
forest dieback
picea abies
species structure
age structure
timber harvest
threat to forests by wind
Opis:
In the Beskid Żywiecki, the combination of abiotic, biotic and anthropogenic factors unfavourable for the growth of trees led to the dieback of spruce stands. The intensification of this process began after the hurricane in November 2004, followed by years of negative climatic water balance. The deterioration of tree growth conditions occurred after the drought in July 2006 and damage caused by the Kyril hurricane in January 2007. The weakened spruces were attacked by the bark beetles, the outbreak of which caused a massive dieback of spruce stands. In order to assess the volume of harvested timber in years 2004−2016, the volume of allowable cut (model volume) was calculated from the stand growth model for each forest district of Beskid Żywiecki. The comparison of the volume of harvested timber with the model volume allowed to determine the rate of dieback of spruce stands. The volume of harvested timber in 2007−2009 exceeded the model volume even 2.5 times. The cuts included mainly deadwood, wind−broken and wind−fallen trees, while the harvest of live trees was scarce. In the period 2010−2013, the harvested volume of live trees accounted for 50−70% of the model volume, the volume of deadwood in the same period was ca. 100% and additionally the volume of blown−down timber after the hurricane was 20−40% of the model volume, which taken together accounted approximately to 200% of the model volume. The execution of such harvesting operations, including silvicultural tasks, did not allow to carry out optimal forest management. The period 2010−2013 saw a downward trend. It was disrupted by the hurricane in December 2013, after which the volume of harvested timber, consisting mainly of wind−broken and wind−fallen trees, increased to 280% of the model volume. Again, the high volume of harvested timber was noted in 2016, (ca. 220% of the model volume). The process of damage to spruce stands in Beskid Żywiecki is likely to continue. A decline in its intensity may occur in the absence of old stands, which to a large extent already takes place in the forests of the Węgierska Górka Forest District. Currently, the most threatened by wind are forests in Ujsoły, Jeleśnia and Nowy Targ forest districts. The least threatened are forests in the Węgierska Górka. This forest district and in the future the remaining forest districts of Beskid Żywiecki, will face enormous challenges to obtain high yield and appropriate species composition.
Źródło:
Sylwan; 2019, 163, 02; 130-140
0039-7660
Pojawia się w:
Sylwan
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Charakterystyka wybranych drzewostanów jodłowych Beskidu Niskiego i sposoby ich zagospodarowania
The characteristics of selected fir stands in Beskid Niski and the method of their management
Autorzy:
Bruchwald, A.
Dmyterko, E.
Niemczyk, M.
Łukaszewicz, J.
Powiązania:
https://bibliotekanauki.pl/articles/989908.pdf
Data publikacji:
2015
Wydawca:
Polskie Towarzystwo Leśne
Tematy:
lesnictwo
gory
Beskid Niski
drzewostany jodlowe
struktura drzewostanu
liczba drzew
piersnicowe pole przekroju
miazszosc drzew
zagospodarowanie lasu
stand layer
multi−layer structure
bdq method
abies alba
Opis:
Assuming multilayer structure as optimal for silver fir stands, we attempted to answer the following questions: 1) how to describe such structure, 2) to what extent does the structure of a particular stand differ from the optimal one, and 3) how to obtain the optimal structure. The study was based on the material collected in 12 stands in the Nawojowa Forest District (S Poland). Three to five 0.04 hectare circular plots were established in each stand, and diameters at breast height (d) of all trees with d > 7 cm were measured. Height (h) was measured for 25 trees selected within the stand. The top height determined for each stand enabled to classify trees into two layers: higher (group I) or lower (group II) than ⅔ of top height. Trees with d<7 cm were divided into 3 layers according to the height: III – h>2 m (higher upgrowth), IV – h between 0.5 and 2 m (lower upgrowth), and V – h<0.5 m (seedlings). Trees in layer V were counted on a 0.005 ha plot, while trees in layers IV and III on a 0.04 ha plot. The selected fir stands revealed high diversity in basic characteristics (tab. 1 and 2). The number of trees in layer III was higher than in layer II only in one stand, and was larger than the number of trees in layer I. Moreover, the variation in tree height formed a vertical canopy closure. The stand was considered to be a model one, and used to develop diameter distribution according to the BDq method. Most stands characterized a smaller number of trees in lower and larger in higher diameter classes compared to the model distribution. It seems that large number of thick trees prevent satisfactory growth of thinner trees. Fir stands proved to have a mosaic vertical structure. In some fragments, eight classes can be distinguished including one layer only: 1) upper (I), 2) middle (II), 3) upgrowth (III), combination of layers: 4) I and II, 5) I and III, 6) II and III, 7) I, II and III, and 8) gaps. The multi−layer structure of fir stands can be maintained only in the form of such a mosaic, but single−layer fragments are also needed to enhance the natural regeneration. We could select a stand with a close−to−optimal multilayer structure, which was considered as a model one and its diameter distribution was used in the BDq method. A comparison of the model curve with the empirical distribution of diameters at breast height for the stand under consideration allows determining diameter classes with an excess of trees that can be harvested without the fear of losing the multilayer structure of the stand. Whether a given tree has to be cut should depend on the vertical differentiation of trees in a particular fragment of the stand. In further studies, measurements in multilayer fir stands should be conducted to verify the model distribution.
Źródło:
Sylwan; 2015, 159, 09; 722-731
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
    Wyświetlanie 1-3 z 3

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