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ŠUMARSKI LIST 3-4/2013 str. 51     <-- 51 -->        PDF

Biomass of each individual snag and stump root was multiplied by a coefficient 20, in order to convert it into biomass per hectare (t ha–1).
Carbon content was calculated by multiplying the weight of dry deadwood biomass with 0.5 coefficient (IPCC, 2003).
The field data were processed in the laboratory of the Institute of Forestry in Belgrade. Dendrometric analysis was carried out using the computer software EXCEL Microsoft office, 2010, while STATGRAPHICS software, version Plus 5.0, 2000 Statistical Graphics Corp. was used for the statistical data processing.
Results and discussion
Rezultati i rasprava
Deadwood volume – Volumen mrtvog drveta
Using the above described method of work, the data were first processed for each beech stand separately and then for all stands together. Due to high variability of dead wood on the area of the investigated stands and due to the small size of the sample of sample plots (Table 1), the resualts obtained for stands are unreliable. However, the results obtained for all investigated stands together are sufficiently reliable.
The average volume of living and dead wood above ground per hectare in the individual stands and in all investigated beech stands is given in Table 2.
The data in Table 2 indicate the following:
Average volume of dead wood in all beech stands together is 19.24 m3 ha–1, or 9.73–28.01 m3 ha–1 per stands. Lying wood accounts for 11.21 m3 ha–1 or 58.3 %, or 1.24–24.53 m3 ha–1 per stands. Standing wood accounts for 8.03 m3 ha–1 or 41.7 %, or 2.41–12.45 m3 ha–1 per stands.
In the average volume of dead wood of all beech stands together, unprocessed wood acccounts for 9.35 m3 ha–1 or 48.6 %, old stumps for 6.73 m3 ha–1 or 34.98 %, processed wood for 1.86 m3 ha–1 or 9,67 %, and snags for 1.30 m3 ha–1 or 6.75 %.
With regard to the average volume of living wood of all beech stands together (383.9 m3 ha–1) total dead wood accounts for 5.01 %, and snags only for 0.34 %. The share of the total dead wood per stands ranges from 1.93 % to 9.10 % and the snags from nothing to 2.27 %.
The analysis of variance (Table 3) was used to test the statistical significance of the difference between the average values of the aboveground volume of the total stand dead wood per hectare. The difference was proved to be statistically significant, because the obtained value F = 2.68 (p < 0.005).
Duncan`s test shows that all stands can be theoretically classified into two statistically homogeneous groups:
 
In practice, according to the average quantity of dead wood per hectare, the stands can be classified into four groups (Table 4).
Using the average amount of dead wood per hectare, the stands are indirectly classified based on the different variability of deadwood volume in them. In other words, there is a statistically significant linear correlation (r = 0.8304, p < 0.01) between the standard deviation (m3 ha–1) and the average volume of dead wood in the investigated stands (m3 ha–1).
Statistically speaking, these are four strata. Therefore, the assessment of the average and total volume of dead wood of all investigated beech stands together used not only the simple, but also the stratified sample.
However, there is no relationship between the determined volume of living and dead wood per hectare in the studied beech stands (for sample plots n = 242, r = –0.1607 and for stands n = 11, r = –0.46) because it is considerably disturbed by extracting a great quantity of wood from the stands after felling. This relationship exists in natural beech forest reserves and it is statistically very significant (Christensen et al., 2005).