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Wyświetlanie 1-2 z 2
Tytuł:
Ocena zasobów martwego drewna w lasach gospodarczych z względnieniem typów siedliskowych lasu oraz bonitacji gatunku panującego
Effect of site conditions and site index for the dominant tree species on the amount of deadwood in managed forests
Autorzy:
Bujoczek, L.
Zięba, S.
Banaś, J.
Powiązania:
https://bibliotekanauki.pl/articles/989223.pdf
Data publikacji:
2016
Wydawca:
Polskie Towarzystwo Leśne
Tematy:
lesnictwo
lasy gospodarcze
drewno martwe
miazszosc drewna
warunki siedliskowe
typy siedliskowe lasu
bonitacja siedliska
coarse woody debris
snag
volume
site productivity
fertility
moisture
Opis:
The work studied the effects of site conditions on the amount of deadwood (DW) in managed forests in south−western Poland. Measurements included standing dead trees, snags with a diameter at breast height of at least 7 cm, and lying deadwood (logs, branches, uprooted trees, etc.) with a diameter at the thicker end of at least 10 cm. The study excluded snags and deadwood pieces with a diameter of less than 7 cm as well as stumps. Site conditions are presented according to the Polish site classification system taking into account both site fertility and water abundance. With respect of the fertility gradient, sites are classified as dystrophic, oligotrophic, mesotrophic, and eutrophic. In terms of water abundance, there are two types of sites: mesic (low or very low contribution of groundwater, rainwater, and floodwater, with an approximate springtime water table depth of more than 1.8 m) and moist (moderate or considerable contribution of groundwater, rainwater, and floodwater, with an approximate springtime water table depth of 0.5−1.8 m). We analyzed data from 2522 sampling plots with area ranging from 50 to 500 m² and depending on forest stand age. The plots were established in forest stands older than 21 years old. The predominant tree species in the study area were Pinus sylvestris, Quercus robur, Quercus petraea, Betula pendula, Fagus sylvatica, Alnus glutinosa, Fraxinus excelsior and Picea abies. In a separate analysis of data from 233 sampling plots, we studied the relationship between DW volume and the site index evaluated using a five−level classification (level I denotes sites with the highest productive capacity). Forest stands aged >80 years with the dominance of Pinus sylvestris were studied. The study showed a significant influence of site conditions on the DW volume in managed forests. Forest stands exhibiting better site conditions not only provided more timber, but also contributed with a greater amount of deadwood to the ecosystem. Forest stands with a site index of I contained as much as 4.9 m³ of DW/ha, while stands with a site index of III only 2.4 m³ of DW/ha. In terms of the 8 studied site types, it was also found that the average volume of DW increased with site fertility. The lowest volume of DW occurred on very nutrient−poor and mesic sites (0.6 m³/ha). In contrast, nutrient−rich and moist sites contained 15 times as much DW (9.5 m³/ha). Of paramount importance was water abundance. The volume of DW on moist sites was on average by 2.2−4.5 m³/ha higher than on mesicsites with the same fertility.
Źródło:
Sylwan; 2016, 160, 04; 320-327
0039-7660
Pojawia się w:
Sylwan
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Inwentaryzacja martwego drewna statystyczną metodą reprezentacyjną z zastosowaniem warstw gatunkowo-wiekowych
Inventory of deadwood by the means of a statistical representative sampling method using species-age layers
Autorzy:
Bujoczek, L.
Bujoczek, M.
Banaś, J.
Zięba, S.
Powiązania:
https://bibliotekanauki.pl/articles/989002.pdf
Data publikacji:
2017
Wydawca:
Polskie Towarzystwo Leśne
Tematy:
lesnictwo
drewno martwe
miazszosc drewna
zasoby drzewne
szacowanie zasobow
metody statystyczne
typy siedliskowe lasu
gatunki panujace
wiek drzewostanu
coarse woody debris
snags
measurements
accuracy
Opis:
According to the current forest management manual, deadwood volume should be evaluated on 10% of sampling plots, located in different species−age layers, which are used for determining stand volume in a given forest unit. Sampling plot size differs depending on tree stand age and ranges from 0.005 to 0.05 ha. The results are reported for the entire forest district and by forest site type. The objective of the study was to analyze the accuracy of deadwood volume estimations in the light of the guidelines stipulated in the forest management manual and to find the ways to improve the obtained results. Deadwood volume was measured on 2752 sample plots used to determine stand volume and the mean value calculated on that basis was 5.4 m³/ha. Subsequently, 30 random draws of sampling plots were performed. Estimates based on randomly selected pools consisting of 10% of sampling plots ranged from 3.5 to 8.6 m³/ha. Subsequently, another 10% of sampling plots were randomly drawn and added to the previous ones. The results for 20% of sampling plots were 4.5−7.0 m³/ha, for 30% – 4.3−6.4 m³/ha, for 40% – 4.6−6.4 m³/ha and for 50% – 4.7−6.0 m³/ha. In the next step, 225 sampling plots located in reserves and special zones around the nests of protected species were discarded. The mean volume of deadwood computed for the managed forest areas alone (2527 sample plots) was 4.7 m³/ha. The random drawing procedure was repeated to give the following results: 3.6−6.8 m³/ha for 10% of sampling plots; 3.8−5.8 m³/ha for 20%; 3.9−5.3 m³/ha for 30%; 4.2−5.3 m³/ha for 40%; and 4.2−5.1 m³/ha for 50% of sampling plots. The categorization of the randomly selected sampling plots by forest site type in most cases yielded results significantly differed from the values computed based on all sampling plots. It was found that estimates based on 10% of sampling plots may diverge considerably from true values due to the uneven distribution of deadwood. In particular, managed and unmanaged forest areas should not be combined due to the high differences in the volume of deadwood between them. If a relatively low number of sampling plots is used, it seems advisable to report results only for the forest division as a whole, without a breakdown into site types. Satisfactory estimates for the different forest sites types would require much more work. The use of a greater number of sampling plots than specified in the forest management manual seems to be a fundamental prerequisite for improving the accuracy of deadwood volume estimates.
Źródło:
Sylwan; 2017, 161, 02; 114-123
0039-7660
Pojawia się w:
Sylwan
Dostawca treści:
Biblioteka Nauki
Artykuł
    Wyświetlanie 1-2 z 2

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