نشریه بوم شناسی جنگل های ایران
پیاپی 15 (بهار و تابستان 1399)

In this research, the status of forests in Ilam city with the aim of preparing the spatial distribution map of oak forests degradation using remote sensing and geographic information system was investigated. In order to achieve the extent and location of degradation in the studied area, the forest area map for 2001 using Landsat 7 ETM+ satellite images and forest area map for 2013 using OLI Satellite Landsat 8 images, Field visits and a method of determining educational samples were prepared. To investigate the factors affecting on degradation, first, the spatial variables including distance from residential areas, distance from roads, slope, aspect and altitude were extracted from topographic maps of 1: 50000. Then the degradation location data of the region forests with the physiographic and human spatial variables was entered the model. For modeling and estimating the spatial distribution of degradation in the study area forests, logistic regression and step-by-step method and forward step type were used. According to the results obtained from the statistical model, the development of human-made areas, population growth, reducing the distance of roads from the forest areas, the middle altitudes and reducing the slope percentage that triggered agroforestry activities and increase of agricultural land area had the highest impact on the degradation of the Ilam city forests, respectively. In fact, of 73349 hectares of forests in Ilam city, 5311 hectares (7.2%) have been reduced, of which 2125 hectares (2.9%) are related to the phenomenon of oak drying and 3186 hectares (4.3%). ) It is related to the construction of settlements, road construction, etc. Based on this, a spatial distribution map of the destruction of forests in Ilam city was prepared.

The studies show that the mean temperature of the Hyrcanian region has been increased by 0.74 siliceous degrees in the twenty recent years. In this research, the current and future distribution of Chestnut-leaved oak (Quercus castaneifolia C.A.M.) was studied using an ensemble method including five different species distribution models. We used five general circulation models under two reprehensive concentration pathway (RCPs) to project the impact of climate change on the distribution of Chestnut-leaved oak by 2070. Also, the stable, gained and lost suitable habitat of Chestnut-leaved oak were determined using range size change analyses under climate change. The results showed that the area of suitable habitats with high certainty would be increased by 16.80%, while it would be decreased by 29.80% under RCP 8.5 by 2070. The results of the range size analyses of oriental beech showed 54.12% of suitable habitat would be stable under RCP 4.5 while it would be decreased by 23.85% under RCP 8.5 by 2070. Also, the gained suitable habitats would be 62.68% and 42.36% under RCP 4.5 and RCP 8.5, respectively. It is suggested that the climate change impacts should be considered in the management decisions and conservation plans related to the Chestnut-leaved oak in the Hyrcanian forests. Further, the suitability of habitats under climate change should be accounted for plantation and reforestation by Chestnut-leaved oak.

This research considers the optimal rotation age regarding to the carbon sequestration value in populous deltoides plantation in Choobar located in Guilan Province, north of Iran. First, the volume increment is determined by stem analysis method and carbon sequestration is determined by combustion in an electric oven. Then, Net present value (NPV) of carbon is calculated by using volume increment, carbon amount, interest rate, adjusted price of carbon and net revenue in order to determine the optimal rotation age. Faustmann model was used in order to determine the optimal rotation age. Data such as volume increment, carbon content, revenue, timber and carbon prices are used to estimate the NPV. The study also evaluates the effects of different cost of plantation and discount rates on the optimal rotation ages using NPV approach. Results showed that when economic value of carbon sequestration is considered, optimal rotation ages is 27 years. Sensitivity analysis is done for interest rate, cost of plantation, and carbon price. As cost of plantation increases, the optimal rotation age also increases and the net present value decreases. With the increase in carbon prices, the age of optimal rotation age decreases and the net present value increases.

Colutea persica is one of important and valuable species in Kandiragh forest reserve of Khalkhal. This study aimed to determine the relationship between Growth properties of Bladder Senna with soil and physiographic factors in Kandiragh forest reserve. in three land forms (ridge, valley and slope) and in four aspects (north, south, east and west) from lower to higher distribution areas sample plots, each 500 m2, were selected. Overall, 32 sample plots were used for measuring Growth characteristics; soil characteristics were studied in 12 sample plots including soil texture (clay, silt and sand), pH, Ec, N%, OC% and Caco3%. The results showed that the distribution range of Bladder Senna varies from 1350 to 1980 m.a.s.l. In general, slopes and ridge forms with south and east-facing slopes are suitable sites for this species. The highest figures of Bladder Senna individuals including height (1.75m), crown diameter (1. 81 m) and regeneration (169.N/h) on valley form and the highest number of shoot (13/11) on slope form were measured. Soil of Bladder Senna habitats is deep to semi- shallow with pH (7.4 to 8.1), Ec (0.21 to 0.39 ds/m) and with soil texture of loam to loam- sand. The PCA analysis showed that the physical properties of soil (sand, clay and silt) and Ec have an important impact on the presence of this species. So that, the presence of Bladder Senna in the southern and eastern slopes has more correlation with silt percentage.

The objective of this study was ecological assessment of the Danish and Swiss thining methods in 20-years old reforestations of Brutia Pine (Pinus brutia Ten.). This research conducted under completely randomized block design (CRBD) with three replication and three treatments (Swiss and Danish thinning methods and control); a total of 9 plots each 2000 m2 (40 x 50 m). The quantitative and qualitative parameters of trees were measured by full callipering in each plot. In order to investigate the species diversity of plants and the natural regeneration in each plot, three micro samle plots of 49 m2 were randomly selected. Sampling of soil invertebrates was performed from a depth of 0 to 10 cm in the center of each micro sample plots. The parameters were measured in the years of 2013 (before thinning) and 2018 (five years after thinning). This study showed the mean diameter at breast height (dbh) and mean height of Brutia trees and the whole stands, as well as, simpson plant diversity and soil invertebrates' diversity between treatments were not statistically significant in 2018. Mean dbh of the whole stand and Pine trees were accounted to 17.02 cm and 22.74 cm in Danish method, 16.94 cm and 21.71 cm in Swiss method and 15.59 cm and 19.53 cm in the control plot. Mean height of the whole stand and Pine trees from Danish and swiss methods to the control plot were accounted to 11.13 m and 13.19 m, 10.88 m and 12.68 m and 11.44 m and 13.58 m, respectively. The average species diversity of Shannon plants in the field of Danish thinning was significantly higher than the Swiss method and the control area. Also the Simpson plant diversity was higher in the Danish method, followed by the control and the Swiss method, while the soil invertebrates’ diversity was higher in the Swiss method followed by the control and Danish method. Also the results of this research showed that the quality of the Brutain Pine and the whole stand in the thinned treatments were better than that of the control plot in 2018 (ρ=0.05). This research emphasizes the need for thinning operations in the forest plantations.  Over all this research suggests application of the Danish method in Brutia Pine plantations in terms of increasing the quantitative and qualitative characteristics of trees, along with the increasing of plant diversity

Knowing the qualitative and quantitative characteristics of plantation is principal of forest management. Laleh Natural Park in DEZFOUL, with a total area of 9.31 hectares, is located 11 km far from Dezful. The 23-year old stands in the studied park were Eucalyptus and Prosopis. In order to study the number of trees, according to the small levels of the studied stands (pure Eucalyptus 1.9 hectare and mixed with Prosopis 1.7 hectare), the full calipering inventory method was selected and the certain characteristics such as diameter at the breast height and height of all trees. According to the results, the average number of trees in the pure Eucalyptus stand is equal to 110.5 trees per hectare, the average diameter at breast height of stand is 25.22 cm and the average total height is 12.10 m. Also, the average number of species in the mixed Eucalyptus and Prosopis stand is 70.6 trees per hectare, the average diameter at breast height is 27.32 cm and the average total height is 9.57 m. In order to study the effect of Eucalyptus and Prosopis on the soil of the area, 50 soil samples were taken at 2 depth of 0-10 and 10-20 cm from pure and mixed stands and some soil characteristics including texture, moisture and acidity were studies. Soil texture of both stands in this study was loam. There was no significant difference between the two populations in terms of total relative humidity. In terms of acidity, there was a significant difference between two soil depths of 0-10 and 10-20 cm soil in the pure stand which was higher at depth of 10-20 cm.

In this research, important habitats of the species of salix in Chaharmahal and Bakhtiari province were identified. Then, one-year branches were produced for the production of cuttings. Then the seedlings were transferred to the main field of the project and surveyed for 8 years. Height, DBH and diameter of the canopy were measured. Also pests and diseases of the trees were investigated continually. The results showed that five species including Salix excelsa S.G.Gmelin, Salix acmophylla Boiss., Salix alba L, Salix elbursensis Boiss and Salix-issatisensis were identified in this province. Quantitative studies showed that Salix alba L (206) with 7.86 m height and 16.12 cm DBH and Salix alba L (208) with 18.66 m2 of canopy surface were better than other species and have high resistance to cold and frost. The results of pests and diseases also indicated that 8 species of pest were existing on all Salix species.

The study of the litter quality and soil enzymes activities are used as indicators for soil quality and soil health assessment. The aim of this research was to investigate the effect of different vegetation types of Vaz forest of Noor-Mazandaran Province (i.e. Fageto-Carpinetum, Fageto-Aceretum, Fageto-Quercetum and Fagetum) on litter quality and activity of some of the most important soil enzymes. For this, eight samples of litter and soil (0 to 15 cm) were collected within the forest types in growing season. The ANOVA of litter, soil physio-chemical and enzymes activities rate indicate a significant statistical difference among forest types. The highest amounts of litter thickness (15.15 cm) and C/N ratio (79.08) were allocated to the Fagetum type and the least amounts of litter thickness (8.09 cm) and C/N ratio (42.15) were found under Fageto-Carpinetum type. The results showed that the highest activity rate of urease (23.14 µg NH4+–N g−1 2 h−1), acid phosphatase (521.12 µg PNP g−1 h−1), arile sulfatase (129 µg PNP g−1 h−1) and invertase (210.37 µg Glucose g−1 3 h−1) were significantly observed under Fageto-Carpinetum forest type. Based on findings, the soil of Fageto-Carpinetum forest type has better quality compared to other studied types. The results of this research can be helpful for prioritizing of forest stands based on plant residual and soil quality.

Fire is a big threat to natural resources in the world and is an important factor in changing the physical and chemical characteristics of the soil. The purpose of this study was to investigate the effect of fire on the physical and chemical properties of the soil in oak forest of Badreh located in 70 km of Ilam province and to compare it with unburnt (control) areas. Soil sampling carried out in two topsoil (0-5cm) and subsoil (5-20cm) depths. Five plots in 50×50m dimension designed in burnt and unburnt forests and in each plot 5 soil samples were collected randomly from topsoil and subsoil and were transferred to the laboratory to soil physical and chemical analyses. According to the results fire increased the amount of sand and silt by 15.56%, 15.18% respectively, compared with unburnt forest. But, the percentage of clay decreased under burn condition. Fire declined aggregate stability in soil 0-5 and 5-20cm depths by 10.61 and 17.81 respectively. The most CEC content (20.98 cmol/kg) and the least one (16.56 cmol/kg) was observed in unburnt forest comparison with burnt forest respectively. Burned increased soil organic carbon but by increasing soil depth decreased it. In the study area, fire affected significantly K and P available in forest soil. To sum up, fire changed soil physical and chemical properties of oak forest in Badreh region in Ilam Province as well as this phenomenon increased essential nutrient elements resulting from soil fertility improvement in the study area.

The decline of forest trees has always been one of the main problems of various ecosystems. Today’s, this phenomenon is occurring in the natural resources and forests of Zagros, and has a wider dimension every day. Various biotic and abiotic factors have been identified and introduced in different countries as the main factor or factors affecting the weakness, dryness and death of oak trees. But in Iran, the factor or main factors of the trees decline in the Zagros forest have not yet been determined accurately. The incidence and severity of this phenomenon in recent years due to the importance of forests in the province of Ilam from the viewpoint of in environmental issues and their becoming generous to oak decline, have been investigated. For this purpose, in the present study, in the multi-criteria decision-making space and the use of the AHP hierarchical process, six main criteria and a total of 28 sub-criteria were evaluated. The weight of each criteria and sub-criteria was computed by distributing 30 special questionnaires of forest specialist and obtaining opinions from experts group and using Expert Choice software version 11. The results showed that the highest weight was for drought and climate change (0.289), and the lowest weight for the quantitative and qualitative criteria of the tree and its forestry characteristics (0.097). Other criteria In order of importance were; pests and diseases (0.194), human and animal factors (0.192), air pollution (0.123) and site quality of habitat (0.105).

Investigating the growth and production of afforestation's is effective to improve the management of these stands and the prosperity of the future afforestation's. Natural forests' rest plan has attracted the attention of forest specialists and beneficiary's towards the forest plantations. The present study carried out in order to investigate the specification of 32-year-old loblolly pine (Pinus taeda L.) and Chestnut-leaved oak (Quercus castaneifolia C. A. Mey.) plantations in Shen-Rood Watershed No: 25 of Guilan province. In each region, 5 sample plots with 4r area in the form of systematic method with 100×500m Network Dimensions conducted in the study area. Then trees diameter, total height, trunk height and some qualitative characteristics of the trees, including the crown symmetry, forking and curvature of the trunk were recorded in each plot. Also, five soil samples were taken from four quadrants and center of each plot from 0 to 30 cm depth, then combined and transferred to the laboratory in order to investigate the properties of the soil. The results indicated insignificant difference between the quantitative characteristics of two stands, such as mean height, basal area, volume and slenderness coefficient. However, the mean length of the branchless trunk of loblolly pine stand (11.33 m) was higher than Caucasian oak (6.6 m). Also, it was no significant differences between two stands in terms of symmetry. However, the pine stand trees had a less curvature (14%) and forking (16%) than it in Chestnut-leaved oak stand (35% and 37% respectively). Investigation of soil samples showed that there is no significant difference between two stands in about sand, particle and bulk density and carbon percentage but clay and silt (42.28% and 26.29%), Microbial respiration (1.86 gram carbon dioxide in soil per day), pH (5.71), porosity (21%) and Soil saturated water content (37.95%) had a significant difference with the Chestnut-leaved oak mass (25.09, 48.70, 2/79, 29, 6.31 and 18.33). Finally, considering the similarity of other conditions, soil texture reported as the main limiting factor of loblolly pine growth. Therefore, planting of the Pinus taeda species is recommended in order to gain more volume production in moderate, lightweight and appropriate drainage areas and planting the Quercus castaneifolia is recommended for revitalization of damaged and ruined areas.

In this research, the role of altitude at Juniperus trees growth rings width in North Mountains of Kerman province has been investigated. Juniperus is one of the main pillars of natural ecosystems in Iran's mountainous forests. High mountains with vast expanse in Kerman province has caused the formation of tree coverings such as Juniperus and has created suitable habitats for Dendrochronology studies. However, most of the Dendrochronology studies in Iran are related to Zagros, Alborz and Hyrcanian forest, and no research has been carried out in Kerman province. The habitat of this study is located in the northern mountainous area of Kerman province, almost among the three counties of Ravar, Zarand and Kuhbanan. In this research, 128 cores from 64 Juniperus trees has taken in 4 sites of habitat by using an Increment Borer. These 4 sites and the difference in altitude between the lowest and highest trees of them are Kooh-e-gav 349 meters, Bid-e-shikh 401 meters, Rood-e-kor 478 meters and Galouband 215 meters. After preparing the samples and enhancing their visual clarity, the number and width of the rings were counted and measured by LINTAB and TSAPWin software with a precision of 0.01 millimeters. The Cross-Dating between two cores of any tree was performed by TSAP and the results of GLK, CDI, GSL, CC, and T-v statistics showed the optimum quality of Cross-Dating for growth series that obtained from the trees. The relationship between altitude differences and average ringwidth was measured using Pearson and Spearman correlation coefficients for 3 sites and all trees. Results of Pearson coefficients (Kooh-e-gav: -0.67, Bid-e-shikh: -0.75, Rood-e-kor: -0.59 and all trees: -0.45) and Spearman (Kooh-e-gav: -0.70, Bid-e-shikh: -0.79, Rood-e-kor: -0.33 and all trees: -0.30) showed that between the altitude and average ringwidth variables in the first two sites, the negative correlation is high, and on the third site as well as the all trees, there is a moderate negative correlation.

Project time and cost are one of the issues and challenges that employers and contractors are facing whit them especially in the forest area. One of the most effective tools that used in prediction and risk analysis is Monte Carlo analysis that Based on the production of random numbers, the number of single components of a set is computed and find out their effect on the whole set. In the traditional approach to project control that still dominates in most national projects, estimating the probable time and budget of the project is still unpredictable to managers and experts. In this work, we tried to present a model for considering the probability and risk in estimating the probability of completion of the project by given time and cost of project termination in a forest area using a case study and software capabilities (Primavera Pertmaster). The results of the probability distribution revealed that the probability of reaching the predicted budget was approximately 13% according to the Monte Carlo simulation. However, the difference between the maximum and minimum values varies from 39 to 650 million IRR, which results in a high risk of the operation of the land operations, which indicates the high risk of the earthwork operation. The real cost of earthwork (570 million IRR) in the study area at the cost allocation chart is estimated at 90%, which also confirms the riskiness of the road earthwork project. Finally, the Monte Carlo simulation method, with the successful prediction of the risk of earthwork operation project, showed that there is an acceptable way for contractors and forest road designers to deal with the negative aspects of the project. The results of this research can be used as a guide to better management of forest for future operations.

In order to evaluate the efficiency of sampling indices in the spatial pattern of 4 wooden species (Quercus brantii, Crataegus aronia, Pistacia atlantica and Acer monspessulanum) an area of 500 hectares of Kalkhani forests of Koudasht city, Lorestan province was selected. The regular 100 m × 300 m grids in Arc GIS software were maked and taken with random starting point on the map of case study. The geographic position of 141 circle sample plots with area 1500 m2 (Which is the starting point for the distance-based methods) was entered in  Global Position System (GPS) set. The number, species, and crown cover of each base were recorded for spatial pattern analysis. The methods of study spatial distribution pattern were used density based indices (such as: Variance-to-Mean Ratio, Index cluster, Green, Moresita and Standardized moresita) and distance based indices (such as: Johnson and Zimmer, Eberhart, Hopkins, Hinez and C index) were accomplished by using of Ecological Methodology software. The results indicated that Quercus brantii and Pistacia atlantica have the highest and the lowest numbr of tree in case study, respectively. Also the basis of the results the highest and the lowest canopy cover area belong to Quercus brantii and Crataegus aronia, respectively. All of the density-based indices showed a clumped pattern for 4 trees species. Among the distance-based indices, Eberhart and Hinez presented better results than the other indices. In general, the density-based indices performed much better than the distance-based indices in this research. The comparison of the methods showed that each one can be applied, regarding the goal and available circumstances of future studies.

The Increase in studies of beta diversity has led to several measures and methods. The variety of theses indicators cause their use in confusion. The aim of this study was to evaluate and determine the relationships between 18 different beta diversity indices based on presence and absense data. For this purpose, Buxus hyrcana database in Golestan and Mazandaran provinces was used. Clustering results showed that these 18 indices classified into 4 distinct groups with similar performance. Evaluation of clustering results by Detrended correspondence analysis (DCA) analysis showed that the indices of the four groups of cluster analysis can be separated into three distinct groups. From basis of combined results of discriminant analysis and Braun-Blanquet method, three vegetation units were recognized, which had 64.1 percent coincide with phytosoicilogical plant communities in Braun- Blanquet method. Also, among of 18 beta diversity indices included in the discriminant analysis, only Bm, Bc, B-2, Brlb, Bco, BI and Be were added in three functions. Among these 7 indices, them, Bm, Bc, BI and Be had a high canonical correlation with the three discriminant analysis functions. totally, the results of this study showed that many beta diversity indices based on presence and absense data have similar performance, and the numerical values of beta biodiversity indices are a good criterion for identifying Buxus hyrcana plant communities, provided that species turnover in these plant communities being high.