مجله پژوهش و توسعه جنگل
سال چهارم شماره 4 (زمستان 1397)

Proper forest management needs quantitative and precise estimates of forest stands characteristics. Remotely sensed imageries, due to accurate and broad spatial information, has become a cost-effective tool in forest management. Classification of forest attributes and generation of thematic maps are among the common applications of remote sensing. The objective of this study was to optimize Random Forest algorithm for classification of quantitative attributes of Manesht forest in Ilam Province. Two parameters including mtry= 8, 8, 6 and ntree =300, 800, 200 were used as the optimum numbers to classify basal area, canopy cover and density, respectively. The results showed the more accurate classification in canopy cover (overall accuracy=83%, Kappa coefficient=0.73), basal area (overall accuracy=78%, Kappa coefficient=0.72) and density (overall accuracy=75%, Kappa coefficient=0.69), respectively. Furthermore, variable importance index indicated distance-based vegetation indices are more important for basal area and density classification. It is concluded that the Random Forest algorithm as a non-parametric method could classify basal area, canopy cover and density properly.

Study on different parameters of vegetation, especially, on ecological groups can help us to understand environmental factors affecting it. In order to studying of biodiversity, life forms and chorology in different ecological groups in protected area of western Dena forests with 600 ha area were done. Then 50 plots of 450 m2 with dimensions 15×30 meters were established by random-systematic method. TWINSPAN analysis results showed that there were four ecological groups, Smyrnieto-Schumanniatum (first group), Phlometum olivieri (second group), Prangoetum ferula (third group) and Junipereto – Ferulagatum (fourth group) in this area from low to high altitudes, respectively. Different parameters of alpha biodiversity between groups were not significant, although richness value of fourth group was lowest. Beta biodiversity results showed that first group and fourth groups had highest and lowest amount. Also results of life form showed that the first and second groups had higher amount of Therophyt, but phanerophyt species of third and fourth groups were higher than other two groups. On the other hand, fourth ecological groups had the lowest Irano- touranian chorotype and the highest Irano- touranian and Euro-Siberian chorotype. In addition, results showed that first group should be conserved in aspect of plant diversity. Also climate of this group is drier than other ecological groups.

With the development of urbanization, humans gradually shifted away from nature and, to the same extent and the environmental, physical and spiritual needs of man to the green space are increased. The objective of this study is to locate areas prone to developing urban forestry in the metropolis of Tabriz, from the point of view of the necessity of development and the need of citizens (not ecologically) and present developmental solutions. 14 criteria were chosen as standardized in format of Raster maps based on previous research and expert opinions. The pair comparison table comprised the criteria and the weight and importance of each criterion were calculated. After completing the multi-criteria evaluation process, the final map of the priority areas for the development of urban forestry was produced and the area and the percentage of the first, second and third priorities were calculated. Accordingly, 29.8% of the Tabriz area has the highest priority for the development of green space. In the next step, by overlaying the finalized map with the current land use map, the area and percentage of each of the first, second and third priorities located in the current land use classes were obtained. Comparison of these maps showed that 50% of the priority areas for urban forest development, were located in the existing residential areas, 39% were in vacant fields, 9.5% were in agricultural lands and gardens, and 1.5% were in the current green space. These results indicate excessive and unbalanced construction accumulation in most municipality districts of Tabriz. Therefore the general policy in these areas should be stopping new construction and prioritize changing the worn out texture of the city to green space.

The present study was carried out to investigate the effect of two species of Pinus eldarica and Robinia pseudoacacia on soil properties and carbon dioxide emission in the Khargoosh dareh forest park in Tehran. For this purpose, four plots of 20 × 20 meters sample were selected randomly and soil sampling was carried out from the center of each sample plot at a depth of 10 cm. Also the carbon dioxide emissions were measured at 35 points per stand. In order to investigate the effect of seasonal variation on Co2 emissions, measurements were done in both spring and autumn. The results showed that Robinia pseudoacacia increased potassium, nitrogen, phosphorus, electrical conductivity, organic carbon and nitrogen sequestration in soil compared to Pinus eldarica, but the acidity, organic matter, calcium carbonate, bulk density, moisture content, soil texture and carbon sequestration did not show any significant difference between two species.

e aim of this study was to assess spatial distribution of roots by Carpinus betulus trees in Patom district of Kheyrud forest. For this purpose, five trees at small, medium and large diameter classes were selected randomly (totally 15 trees). In order to measure root area ratio (RAR), three soil profiles were dug at both up and down sides of trees (size 50×100 cm) by wall trench method at the horizontal distance of 1, 2, and 3.5 m from tree stem (totally 90 profiles). 10 cm horizons were identified on wall trenches and all of the root diameters were measured. Finally, RAR was calculated for each soil horizon. The RAR was decreased logarithmically by increasing the soil depth. The results of ANCOVA showed significant difference between roots distribution at small, medium and large classes. The results of t-test showed that the value of the index at first, second and third trenches wall of small class at upside significantly more than down side. At medium diameter class only third trench of upside significantly more than down side. At large diameter class, first trench of upside was significantly greater than first trench of down side. The results of this study increase our information about vegetation role in stabilizing slopes and will improve the modeling of slope stability accordance to the DBH classes.

In this article, possibility of using of plant seeds of Lallemantia, Sand plantain and chia also tragacnth (50, 100 and 150 g/l), starch of wheat and corn (100, 150 and 200 g/l) instead of agar (6, 7 and 8 g/l) in MS medium by 4000 years old of Abarkooh cypress explant (Cupressus sempervirens var. horizontalis) was investigated. After 30 days of shoot explant establishment in culture medium, percentage of browning, degree of greening and the number of new buds were evaluated. According to the results, the highest and the lowest percentage of browning were obtained in 50, 100 and 150 g/l of chia and agar treatment respectively and it did not show significant difference with starch of corn, sand plantain and lallemantia seeds treatments. With increasing the concentration of materials, percentage of browning decreased. The highest degree of greening was observed in 150 g/l lallemantia and sand plantain seeds and 200 g/l starch of corn treatments and it did not show significant difference with agar (6 g/l). The lowest degree of greening was obtained in two concentrations of 150 and 200 g/l of chia seeds treatments. The highest number of buds was observed in agar treatment by concentrations of 6 and 7 g/l. According to the results, among different investigated materials in this paper, starch of corn was the best and it is also cost-effective compared to the agar.

Arid and semi-arid ecosystems cover about one-third of the world's dryland and is one of the most vulnerable ecosystems due to periodic droughts and increased use of water resources. This study aimed to evaluate the distribution of rain (stemflow, Interception loss and throughfall) in the Tamarix arceuthoides over a period of rainfall (December 2015 to April 2016) in the riparian forests of Maroon. In order to measure the total rainfall, three plastic collectors were placed in open field and closed to the study stand to collect the gross rain. Tress were divided in three classes based on the tree diameter. Three individual tree were selected in each diameter classes for stemflow measurement. Througfall was calculated using the 50 plastic collectors that were placed 10 m apart in the studied stand. The results showed that the stemflow, throughfall and interception in the fall and growth seasons, are, 3, 62, 35, 2, 53, 45 percent respectively. There was significant positive correlation between gross rain (GR) and interception in growing and non-growing seasons. Furthermore, increasing in the total rainfall values, will result in the stemflow, throughfall and rainfall interception increment. But the interception had reduction trend by increasing the gross rainfall. Our result indicated that increasing in tree diameter can result in stemflow reduction. Our result showed that about 45 percent of precipitation will be out of reach by forest floor and return to the atmosphere by evaporation.

Looking at the different stages of wood logging operations in north forest of Iran we will see that a huge amount of data is collected and in various traditional and digital methods are stored. Todays, despite the emergence of new database and databank systems, unfortunately, most of the General Natural Resource offices of Iran even in the northern provinces, do not have any comprehensive and smart information system and database so that massive amount of information from various stages of harvesting operations could be collected and stored efficiently. To facilitate in storage, processing and delivery of harvesting information of north forest, a harvesting database system using Entity – relationship data model was designed. Access software version.2016 was used to implement the entity- relationship data model or physical design of database system. The designed system includes several components or subsystems (marking of trees, cutting, re-measuring, grading, wood extraction from the forest field and depot, districts certification, forestry plans, forestry plans executives, and out of forestry plans cutting licenses). Using the designed system, the information and data requirements for further investigation and processing from forest harvesting data for forest management decision making can be provided. Entity – relationship data model was designed. Access software version.2016 was used to implement the entity- relationship data model or physical design of database system. The designed system includes several components or subsystems (marking of trees, cutting, re-measuring, grading, wood extraction from the forest field and depot, districts certification, forestry plans, forestry plans executives and out of forestry plans cutting licenses). Using the designed system, the information and data requirements for further investigation and processing from forest harvesting data for forest management decision making can be provided.

The aim of this research was analysis of the effect of harvest intensity on the volume growth of valuable beech forests in the North of Iran. For this reason, volume growth of stand trees were estimated by permanent sample plots during a 10 year period in three parcels with different harvest intensities of Low, medium, and high (6, 13.1 and 18 m3/ha, respectively), and in a protected parcel (control) in Asalem Nav mixed beech forests. Results indicated the harvest intensity had significant effect on the stand volume growth (P