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ŠUMARSKI LIST 11-12/2016 str. 44     <-- 44 -->        PDF

RSE= 0.80).  The best model for estimating bark biomass was model number 2 (R2=0.90, RSE= 0.64) and model number 9 for the least fit (R2=0.51, RSE= 1.38). The best allometric equation for stem biomass estimation was model number 10 (R2=0.95, RSE= 0.50) and the least one was model number 1 (R2=0.91, RSE= 0.68). The model number 10 (R2=0.96, RSE= 0.36) was the best fit model and the model number 1 (R2=0.91, RSE= 0.57) was the least fit model for estimating the total above-ground biomass of Calabrian pine tree. Table 4 depicts the fitting statistics of the selected allometric equations for estimating above-ground biomass of each tree components.
One of the advantages of the fitted allocation equations was to provide accurate estimation of above-ground tree biomass if an adequate statistical sampling design and large number of sample size (>100 trees) were taken as reported by Chave et al. (2004) and Miguel et al. (2014). Many researches (Sun et al. (1980), Bilgili and Kucuk (2009), Durkaya et al. (2009), and Zianis et al. (2011)) estimating the Calabrian pine tree’ above-ground biomass were taken small number of samples (14, 35, 33, and 12, respectively). Miguel et al. (2014) took 201 sample trees, whereas in this study, a total of 292 trees were randomly selected for precise estimating of above-ground biomass of tree components.
The size distribution of this study (ranged from 0.40 cm to 62.0 cm) was wider than any other studies in the region (Miguel et al. 2014: 2.3-55.8 cm; Sun et al. 1980: 9.0-39.8 cm; Bilgili and Kucuk 2009: 13.0-19.0). The dbh and large sample variability of sample trees in size increase fitting between observed and predicted values and provide unbiased biomass estimates for the smaller trees (Navar 2009). However, inclusion of trees that less than 8.0 cm in this study helps unbiased prediction of fire behavior about forest fuels in the fire-prone Calabrian pine stands (Bilgili and Kucuk 2009; Matropolous et al. 2016).
The correlation between biomass and dbh and/or tree height were found strong as expected and reported on the other studies (Ketterings et al. 2001). However, inclusion of the tree height as the second estimator decreased residual varia­tion by % 4 for branches, % 0.2 for needles, % 5 for barks, % 8 for stems, and % 8 for total tree biomass, respectively.