DIGITALNA ARHIVA ŠUMARSKOG LISTA
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| ŠUMARSKI LIST 3-4/2013 str. 53 <-- 53 --> PDF |
total dead wood per diameter classes is irregular, with the greatest percentages in classes 11–80 cm (86.9 %). A sample of 242 sample plots shows that the distribution of the total dead wood above ground per hectare is highly positively skewed (α3 = 2.96) and highly elongated (α4 = 11.05) in comparison to the normal distribution. Arithmetic mean is 19.24 m3 ha–1. Standard deviation is 20.78 m3 ha–1. Standard error is 1.34 m3 ha–1. Coefficient of variation is 108 %. With the probability of 95 % and degree of freedom 241 (z = 1.96), the relative sampling error is +/– 13.61 %. If we apply the stratified sample, with the probability of 95 % and degree of freedom 238 (z = 1.96), the relative sampling error is +/– 13.01 %. It follows that the data on deadwood volume obtained by applying a simple sample and a stratified sample in all beech stands together of about 240 ha are reliable. According to the stratified sample, the confidence interval (p = 0.95, n-4 = 238), for the average deadwood volume is 16.74–21.74 m3 ha–1, and for the total volume 4049–5259 m3. Based on the data from 86 investigated beech forest reserves across Europe, Christiansen et al. (2005) have showed that the average volume of dead wood amounts to 130 m3 ha–1 and it varies from almost nothing to 550 m3 ha–1. However, the volume of dead wood is 10 to 20 times lower in managed (production) forests. In other words, the results of the investigations conducted in Finnland, Sweden, Germany, France, Belgium and Switzerland show that the average volume of dead wood in managed forests was less than 10 m3 ha–1 (Christensen et al., 2005). In comparison to these results, the determined deadwood volume in the managed beech stands in Serbia is almost two times higher, which can be of great importance for the conservation of the general biological diversity. There is only the question whether the determined quantity and structure of deadwood volume per hectare is the optimal one, with regard to soil fertility maintenance and needs of different plant and animal species. The results of volume of dead wood in the beech stands of Serbia are similar to the results obtained by Atici et al. (2008). Namely, according to these authors the total volume of dead wood of managed native Oriental beech stands is 22.87 ± 4.34 m3 ha–1. Stojanović et al. (2005) state that there are about 350 000 ha of beech high forests in Serbia. Therefore, based on the obtained results, the deadwood volume in beech high stands can be expected to amount to about 6.73 million m3 or to range in the confidence interval (p = 0.95) from 5.81 to 7.65 million m3. Deadwood biomass and carbon – Biomasa i zaliha ugljika mrtvog drveta The average dry biomass of dead wood and carbon stock per hectare in the individual stands and in all investigated beech stands is given in Table 7. The data in Table 7 indicate the following: The average dry biomass of the aboveground dead wood of all beech stands together is 6.06 t ha–1, and 2.95–9.20 t ha–1 per stands. The average carbon stock in this biomass amounts to 3.03 t C ha–1, or 1.47–4.60 t C ha–1 per stands. The average biomass of the belowground dead wood of all beech stands together is 17.34 t ha–1, or 3.44–31.56 t ha–1 per stands. The average carbon stock in this biomass is 8.67 t C ha–1, or 1.72–15.78 t C ha–1 per stands. The average biomass of the belowground and aboveground dead wood of all beech stands together is 23.40 t ha–1, |