ECOLOGY OF IRANIAN FOREST
Year:2015 | Volume:3 | Issue:5 |Papers Count:7

Due to variances in response of different tree species in different habitats to climate changes, further studies in this field is clearly required. On the other hand, the lack of studies on chronology to evaluate the effect of solar radiation on radial growth of tree species due to lack of long term data of an important climatic variable, new approaches to determine the effect of this parameter on growth diameter is inevitable. The main objective of this study was to evaluate the effect of temperature and irradiance climatic parameters on growth of diagonal oak (Quercus castaneifolia) as one of the main tree species of forests in Iran. For this purpose, 17 harvested Quercus castaneifolia disks from trees in Astara forest were used and chronology of the species and the response of radial growth to temperature and radiation climatic variables were studied. The findings revealed that although the chronology obtained from two perpendicular directions of each disk for 15 disks had the desired result but the chronology obtained from the 15 selected disks with each other reflected the fact that only 10 disks had acceptable results for chronology of Quercus castaneifolia in Astara forest. Results also revealed that both temperature and solar radiation parameters had negativly significant effect on growth of Quercus castaneifolia. The correlation coefficient (R) between the radial growth and these two variables was -0.52 and -0.45, respectively. Therefore, it can be concluded that although both solar radiation and temperature have a negative effects on growth of Quercus castaneifolia, the temperature is more important than radiation. This fact can be related to cloudy condition of weather in the north part of Iran.

Acer velutinum Boiss. is considered as one of the most important of forest tree. Due to the abundant polymorphism and high sensitivity to environmental conditions, using the Peroxidase to study the genetic diversity is very common. The current study aimed to assess the qualitative and quantitative changes of peroxidase in different maintenance conditions of plant samples and also in different vegetative tissues of maple tree. Different tissues (one-year and two-year branches, trunk bark and leaves) were taken from four maple trees. Samples were conserved in three different status, refrigerator (+4oC), freezer (-20oC) and nitrogen liquid (-196oC) until the time of enzyme extraction. Survey of peroxidase qualitative activity showed that 11 isozyme bands were appeared on acrylamide gels in the sections of heavy- and medium-sized molecules. Maximum isozyme bands were emerged for the samples stored in refrigerator. For one-year and two-year old branches, the number of band positions for refrigerator and freezer stored samples was the same. In terms of number of band stations, samples stored in liquid nitrogen was in the next category. For leaf samples, the number of band positions for refrigerator and nitrogen conserved samples was equal and maximum, and the number of bands for freezer stored samples was in second category. The largest number of bands emerged in bark samples were related to those which conserved in refrigerator. Among the all samples stored in refrigerator, maximum quantitative and qualitative activity of peroxidase was related to the trunk bark, leaf and eventually the branches samples, respectively. So, +4oC and trunk bark are the most suitable condition and tissue, respectively, for enzymatic studies on maple.

Zagros forest as a widest forests of Iran, has a special place on economical development and maintain the stability of water and soil. In order to apporopriate planning for this forest information about forest extend during past, present and future is necessary. The present research was conducted to determine the forest area reduction, during 1955 to 1997, Modeling possibility forest extent loss prediction and its relation with physiographic factor and some of socio-economic factors using logistic regression. Exist digital ortophotomosaics was used in this study. After producing forest map, deforested area and Map was produced through crossing two forests map. Forest extent decreasing Modeling and its specially relations with physiographic factosr (slope, elevation and aspect) and socio-economic factors (education, population, type of livelihood in each village, and distance from road, river, village and forest areas) was performed using logistic Regression. Model sensitivity was evaluated using variable substitution and amount of ROC and Pseudo R2. Results showed that 515 ha of forest areas were deforested during 42 years. The result of evaluation showed that achieved model with Pseudo R2 equal to 0.2998 and ROC coefficient equal to 0.8553 adjusted well with the reality and main variable of forest extent had the highest effect on ROC and Pseudo R2 and livelihood type and elevation after that have more effects on model results.

Morphological traits genetically correlated with wood production have been targeted as an alternative to the indirect selection of Poplar trees for high biomass production. So in this study two Populus species (P. nigra and P. alba) growing in Kermanshah, Zanjan and Esfahan provinces were selected to investigate the relationship between various leaf morphological traits and growth characteristics. In order to assimilate environmental conditions, cuttings were planted under randomized complete blocks design with 3 replications.16 leaf morphological traits and 8 growth characteristics were measured in middle and end of growth seasons. Path analysis was applied to estimate the direct and indirect impacts of traits on height. Also the relationships between morphological traits and growing characteristics were determined. Results showed that leaf area was highly correlated with height in P. nigra and had high positive direct and indirect impact on height. Although there was no correlation between leaf area and height in P. albabut leaf area was correlated with 3 another growth characteristics. In general, results showed that the leaf morphological traits can be used in order to select Poplar trees with high growth rate indirectly.

In order to optimize the planning and management of natural resources and the environment, it is essential to know the status of land cover changes over the past decades. Modeling land cover change can provide valuable information for better understanding of this process, determining of effective factors and forecasting of regions subject to change. This study aimed to determine and simulate the distribution and amount of reduced forest cover changes in Malekshahi County in Ilam province using Fusion CA-Markov model during the years 1976 to 2010. To simulate forest cover changes, Landsat MSS of 1976 and LISSIII of 2007 and 2010 images were processed and classified. To investigate the relationship between forest cover changes and human and environmental factors and land conversion utility maps, the logistic regression method was used. Then the land cover and land use map in 2021 was simulated using a combined model of Markov chain and automated cells based on observed changes between 1976 to 2010. To validate the model, simulation maps of forest cover in 2010 were created using CA-Markov model and classified images of 1976 to 2007 years. Comparison of simulated maps with real map from 2010 showing the high capability of classifying these models to simulate forest cover changes in Zagros forests (kappa index=0.83). The results of the model indicate significant reductions in Malekshahi county forest resources.

Woody Debris is structural and functional part on forest ecosystems and plays a key role in nutrition circulation and carbon storage in long time, tree regeneration and biodiversity conservation. For this reason, studies about investigation and determination of the amount, the method of measurement and spatial distribution of coarse woody are very important. To correct planning about coarse woody in Fandoghlou forests, at first febris we should measure the residues with a suitable statistical method. This study carried out with the aim of efficiency evaluation of line intersects sampling to estimate woody debris. To this, transect method applied based on probability, Huber, and Smalian approaches. Comparison the results of census and transect methods by using analysis of variance and Duncan test indicated that the transect method based on probability theory was the best.

In order to map the forest canopy density Bivareh Ilam Landsat 8 satellite data of 22 July 2014 and FCD model was used. The FCD of four indicators of vegetation, soil, shade and the heat index by applying a suitable threshold was and the density of vegetation and forest canopy density map based on FCD in percent respectively. Forest density map obtained, according to the classes provided by the Supreme Council of Forest, Range and Soil of Forest and Rangeland and Watershed Management (7 classes) and a classification (5 classes), were defined. To determine the accuracy of the classified forest density map, a map of the ground reality of the images presented on the website of the Regional Centre spatial data infrastructure updates and spatial resolution are prepared. The highest overall accuracy and Kappa coefficient in the present study, the classification in five classes of 61.34% and 0.42, respectively, were calculated. The classification of 7 classes, the overall accuracy and kappa coefficient was estimated. Therefore we can conclude that in the Zagros forests, semi-massive to massive forest separation efficiency model is appropriate when the separation of the classes with lower density, is not accurate.