Mehrdad Mirzaei, Amir Eslam Bonyad, Mahboobeh Mohebi Bijarpas,
Volume 1, Issue 2 (3-2015)
Abstract
The aim of this research, was to model the height frequency distribution of Quercus persica in Dalab forests of Ilam. In order to investigate the height frequency distribution of trees in the natural stands, 37 transect with fixed length (50m) selected and data were measure based on systematic random patterns with 100m×100m dimensions of network inventory. Finally, height of 209 trees of oak were measured and analyzed. Beta, Exponential, Gamma, Normal, Log-normal and Weibull probability distribution functions were fitted to the height distribution of oak trees. Characteristics of distribution function using the maximum likelihood estimation method was estimated. Empirical probability distribution and theoretical probability distribution was compared using Kolmogorov Smirnov and Chi square tests. The results of the Kolmogorov Smirnov test showed that Beta, Normal, Weibull, Gamma and Log-normal distributions were fitted to data better respectively but the Chi square test showed that Beta and Log-normal distributions had a good capability in explaining the trees height distribution. We concluded that Beta and Log-normal probability distributions can be used for those who want to simulate changes of forests.
Ismaeil Moradi Emamgheysi, Amir Eslam Bonyad, Mehrdad Mirzaei, Iraj Hasanzad Navroodi,
Volume 2, Issue 2 (3-2016)
Abstract
The aim of this research was study of tree species diversity in the Zagros forests of Iran that known as Ardal’s Chartagh protected forests. The total of the study area was 50 hectares. In this way 50 sample plots (circular shape with 1000m2) were measured based on systematic-random sampling method. In each plot species, DBH, species and number of trees were measured and recorded. To estimate of the tree species diversity, Shannon-Wiener, Simpson, Mc Arthur’s N1 and Hill’s N2 indices and for calculation of evenness and species richness Wilson- Smith’s and Margalef indices were used respectively. Also species importance value (SIV) was calculated. The results showed that there are 7 tree species in the study area including Fraxinus rotundifolia Mill., Juniperus polycarpos C. Koch, Cerasus mahaleb (L.) Mill., Quercus brantii var. persica, Pistacia mutica Fischer, Acer monspessulanum subsp. cinerascens and Salix persica Boiss.. Values of Shannon-Wiener, Simpson, Mc Arthur’s N1 and Hill’s N2 indices are 1.23, 0.58, 2.40 and 2.16. Also Wilson- Smith’s and Margalef indices showed that the values of richness and evenness are about 0.84 and 0.77. The results of SIV showed that the highest value of SIV belonged to the Fraxinus rotundifolia Mill. (188.63%) and the lowest value was due to Salix persica Boiss (17.59%). Therefore, conservation of forest stands might be suggested as a suitable approach for increasing plant diversity.
