Showing 5 results for Mirzaei
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.
Hojat Alah Omidi, Javad Mirzaei,
Volume 2, Issue 1 (9-2015)
Abstract
Natural regeneration is the most important principle to maintain and sustain of vegetation in each region, therefore, doing the research about the relationship between natural regeneration and environmental factors can be useful for conducting a better management in these regions.Therefore, this study aimed to investigate the effects of physiographic factors and soil parameters on natural regeneration of trees and shrubs species in the forest of Baye Mountain in Eyvan city, Ilam province. Using systematic random sampling, 27 plots were implemented in the area with a total area of 900 square meters. Then environmental factors (physiographic and soil) and the number of natural regeneration were studied and measured. Correlation analysis showed that Cerasus microcarpa regeneration had positive correlation with OM and Ca and negative with EC. Regeneration of Acer monspessulanum L. had negative correlation with clay, and Amygdalus lycioides regeneration had positive correlation with silt, while there was no significant correlation between other species and other soil factors. The results showed that elevation had significant effects on natural regeneration of Cratagus pontica and Amygdalus lycioides, while the slope of gradient hadn't any significant effect on regeneration. Only, aspect had significant effects on Cerasus microcarpa regeneration, and regeneration of this species in the eastern and northwestern direction was more than other aspects.
Mehdi Heydari, Ali Mahdavi, Elham Jaferyan, Vahid Mirzaeizadeh,
Volume 2, Issue 2 (3-2016)
Abstract
Judas tree belongs to valuable species in Zagros forests. Nowadays, due to the special beauty of this species, it has received substantial attention in afforestation. In this regard, the improvement of seed germination is a suitable way to improve the quantity and quality of producing seedlings in nurseries and the establishment of forest plantation. In this study, the seed germination characteristics and seedling survival of Cercis griffithii in different soil treatments have been surveyed in the nursery of Aivan County in Ilam province. The experiment was set up as a randomized complete design with four treatments each contained 120 pots. Three seeds in plastic pots were sown in nursery soil (Control Control soil- cattle manure (5:1), Control soil- Litter (5:1) and Control soil- Cattle manure- Litter (5:1:1). According to the one-way ANOVA results, significant differences were observed between soil treatments in terms of germination rate, maximum, mean daily germination and germination energy, while there were no significant differences in other germination characteristics between soil treatments. The highest germination rate, maximum, mean daily germination and germination energy were observed in the treatment of Control soil- Cattle manure- Litter. In terms of time, seedling survival decreased from September to March. The results showed that there is a significant correlation between mean daily germination and different soil composition. In general, it can be concluded that germination and survival of Cercis griffithii can be improved using organic compounds in the nursery.
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.
Vahid Mirzaei Zadeh, Maryam Niknejad, Mehdi Haydari,
Volume 3, Issue 1 (9-2016)
Abstract
The importance of vegetation as a dynamic factor affecting the biological conditions requires that a detailed qualitative and quantitative information about its changes be prepared in short intervals. In this study, in order to monitor and predict vegetation density in Venet watershed in Ilam province the Normalized difference vegetation index (NDVI) and Landsat images from 1988 and 2007 was used and vegetation density maps in three classes without canopy cover, thinned and dense canopy covers were prepared. Comparing the extent of vegetation density classes indicated that the extent of bare soil areas have increased as 1158/837 hectares while the extent of thinned and dense canopy covers 360/8277 and 797/9544 hectares respectively has been reduced. Assessing changes in vegetation density showed that from the classes with thinned and dense canopy covers as 1233/4828 and 210/4539 ha respectively have become no vegetation cover class. Also as 246 /2742 and 38 /8255 hectares of the bare soil areas have been converted to thinned and dense canopy cover classes respectively. Using Markov models and automated cells to predict changes in vegetation density showed that the highest and lowest probability of transition to no vegetation cover lands has been seen respectively in thinned (0.5059) and dense canopy cover (0.1023) lands. Finally, assuming a continuation of current trends, watershed vegetation density map of the target for 2020 was forecast. This map shows in the near future the land without vegetation cover will devote itself about 87 percent of this region.
