حسن پوربابائی

Classification of forest sites is one of the most basic tasks for optimal forest management, which has practical and long-term concepts, such as regulating the structure of forests, increasing forest productivity, selecting fast-growing species suitable for afforestation, afforestation. The most productive methods are increasing the yield of wood to facilitate the relationship between supply and demand, revitalizing forests, increasing access to forest resources, and also fulfilling the ecological function of forests. In recent years, the use of different factors to classify habitats has become more and more widespread. This research aims to investigate the changes of the most important soil characteristics in beech habitats in Nav-e-Islam region.

This study was carried out in the series 3 Nav Asalem and in parcels 318, 320, 336 and 350. The desired parcels are located at two heights of 1100 and 1700. Parcel 320 was considered as a control parcel. In order to investigate and determine the types of trees in the surveyed parcels, 84 square samples with dimensions of 20 x 20 meters were taken randomly with a statistical grid of 200 x 150 meters. In each sample plot, in addition to recording the characteristics of slope, aspect and height above sea level, the variables of species type, height and diameter at the breast height of all tree species were taken. Then, the tree types of the target samples were determined using two-way analysis of indicator species (TWINSPAN). To determine the location of the soil profiles, a map of the shape of the land was prepared and considering the variety of habitat features and the area of the shape of the land, 35 sample plots were determined in homogeneous units, and the profiles were dug in these units and soil samples were taken. The soils were collected from horizons A and B. After digging each profile in the desired types, the vertical section of each profile was divided into different parts based on distinguishing features such as color, texture or soil structure. The preliminary analysis of soil profiles was done in nature and then soil samples were taken from each of the separated horizons A and B and transferred to the laboratory. Then, in a dry laboratory environment, after pounding, it was passed through a 2 mm sieve and the most important characteristics of the soil were investigated. To investigate the relationship between soil characteristics and tree types, conventional comparative analysis (CCA), one-way analysis of variance (ANOVA) and Duncan's test were used.

Based on the results of the TWINSPAN analysis, the area is divided into five types of trees, including pure Fagus (F), mixed Fagus –Acer velutinum (FA), mixed Carpinus-Fagus followed Alnus (CF), mixed Fagus-Carpinus (FR1) and mixed Fagus-Acer cappadocium (FR2) was classified. Based on the ranking results, clay percentage, carbon deposition and height above sea level in A horizon have a significant correlation with the positive direction of the first region, and organic carbon, accessible phosphorus and exchangeable potassium and carbon deposition have a correlation with the negative direction of the second region. It showed significant. In B horizon, the percentage of sand and height above sea level showed a significant correlation with the positive direction of the first axis and the percentage of clay, carbon, accessible phosphorus, exchangeable potassium and carbon deposition with the negative direction of the second factor. All five tree types were affected by altitude and clay percentage in A horizon. But (F), (FR2) and (FR1) were affected by clay percentage in B horizon and carbon deposition in both horizons and potassium in A horizon. (FR1), (FR2) and (FA) were influenced by the percentage of sand in both horizons and accessible phosphorus and exchangeable potassium in both horizons. The results of analysis of variance of physical and chemical properties of soil in tree types showed that there is a significant difference between bulk density, percentage of clay, percentage of sand, base saturation, acidity, organic carbon, accessible phosphorus, exchangeable potassium and so on. There is carbon sequestration among the tree types, no significant difference was observed between the characteristics of silt percentage and porosity percentage among the tree types. Also, the results showed that there is a significant difference between the percentage of organic carbon, exchangeable phosphorus and available potassium in two soil horizons, while there is a significant difference between the differences related to appearance, percentage of clay, percentage of silt, percentage of sand, percentage There is no saturation, porosity percentage, acidity and carbon deposition in two soil horizons.

The variety of topographical conditions in the forests of northern Iran and in the studied area is the cause of many changes in plant types and soil characteristics. According to the results of this research, in the types where the beech species is more dominant, the soil conditions are not very suitable, and the mixed types of beech are settled in the habitats with more slope and lower altitude, and the shallowness of the soil and Lack of nutrients is one of the main conditions of the soils of these habitats. The presence of different types in the forest is the result of the interaction of many factors, and it has been shown in this research that soil is one of the most important environmental conditions, and its significant relationship with tree types has been confirmed. Therefore, soil can be used as a suitable indicator to distinguish forest types.

In this study, the physical, chemical and biological characteristics of compacted soil due to tracked skidding (LTT-100A) after 35 years (from 1986 to 2021) of clear cutting operation were investigated in an even aged mixed deciduous stand in Masal forests, Guilan province, northern Iran. Three levels of machine traffic intensity (TI) (low, LT; medium, MT; and high, HT), two levels of skid trail slope (SC) (Gentle, <10%, GS; and steep, ≥10%, SS), two sample locations(SL) (Between track, BT; and On tracks, OT), and two soil depths (SD) (0-5 cm, and 5-10 cm) were considered as independent variables affecting the process of soil profile recovery. The values measured from the abandoned skid trails were compared with those of undisturbed areas to estimate the soil profile recovery rates. Results showed that TI had significant effects on all soil physicochemical (except for soil moisture) and biological properties (i.e., leaf litter, above-and below-ground biomass); all physicochemical and biological properties (except for soil moisture and leaf litter) were affected by SC; the effect of SL on soil texture, density and moisture was significant; and soil texture and density were the only characteristics affected by SD. The values of soil bulk density and penetration resistance on the skid trails were 35% and 49% higher than those of the control area, respectively, while total porosity value was 17.5% lower than that of the control area. Furthermore, soil organic carbon on the skid trails was 20% less than that of the control area. The amount of soil biomass on the skid trails was not recovered after 35 years, so the above and below ground biomass on skid trails were 42% and 46% less than the control area, respectively. The value of leaf litter on the skid trails was 31% less than that of the control area. Overall, the results of this research revealed that the soil of the studied forest is sensitive to the activity of timber harvesting machines. Thus, sustainable forest management needs to reduce the impact of logging within the context of best management practices (BMPs).

This study was conducted with the aim of investigating the effects of fire on the vegetation in Shanderman forests (Guilan province). For this purpose, 60 sampling plots of 400 m2 were taken in a random-systematic Method in the areas of burned and control. The plant species present at the level of the samples were collected and identified, and their Life forms determined based on the Runkaeir's method. The results showed that 60 plant species were identified in the studied forest, 13 species (22%) only in the fire area, 5 species (8%) only in the control area, and 42 species (70%) were observed common in the both regions. The highest frequency belonged to Rosaceae and Poaceae families. In the study of the life forms of plant elements in the burned and control area, phanerophytes and hemicryptophytes were the most present in both regions. The results of the investigation of plant biodiversity indicators showed that the values of species diversity indicators in the burned area were higher than in the control area. DCA analysis showed that the composition of the vegetation in the burned area is not significantly different from the control area. Therefore, it can be concluded that after 12 years of the fire, the vegetation composition of the area has been restored and has become the same as the control area.

This study aimed at investigating the effect of landslides causing by executive activities on some physical and chemical of soil properties in Tonekabon and Ramsar forests. For this purpose, the geographical location of the landslides was collected. Landslides in altitude (<750 and > 750 m), aspect (north, south, east and west), age (< 15 and > 15 years) and slope (< 50 and > 50%) were classified. In the each class, three sample plot (100 m2) were established to measure of soil properties. Soil properties includingpH, organic carbon, bulk density and particle density. Totally, 88 sample of soil were collected. The results showed that the mean of BD, PD, OC and pH in the landslide area were 1.69, 2.38, 2.33 and 6.80, respectively, and in the control area they were 1.64, 2.32, 3.49 and 6.56, respectively.  The study of soil properties under the effect of slope showed that the mean of pH and OC in the control area was higher than landslide areas, but the BD in the control area was less than the landslide area. Soil properties recovery showed that except soil OC, other soil properties were fully recovered. The statistical results of soil properties showed that there was a significant difference between the mean OC in landslide and control areas in all studied classes.

The aim of this study was to identify the composition and diversity of plants in the Persian ironwood habitat in the Chefrood forest in western Guilan province. For this purpose, five one-hectare sample plots were randomly selected in less disturbed Parrotia persica stands. All tree and shrubs species were identified in each sample plot. Also, 16 micro-sample plots of four-square meters in each sample plot were executed by randomized systematic method and all herbaceous species were identified and recorded. The life form of species was determined using the Rankier method, geographical distribution of species was classified using Zohari method and total biodiversity was determined using Simpson heterogeneity, Menhenick richness and Smith-Wilson evenness. The results of the study of habitat vegetation showed 71 plant species belonging to 59 genera and 43 families. The family of Rosaceae with eight species and Cyperaceae and Poaceae each with four species were the richest plant families in this habitat. Phanrophytes with 44% and hemicryptophytes with 25% had the highest percentage of biological form. In terms of geographical distribution, the highest frequency was obtained with 52% related to Siberian European elements. Also, richness diversity and total element uniformity were calculated to be 0.86, 1.08 and 0.65, respectively. According to the results of the present study, the Persian Iron-wood habitat of West Guilan is one of the various Hyrcanian habitats.

In order to investigate the effect of conservation on vegetation and biodiversity, two areas were studied. The main objectives of this study were to investigate the effect of conservation on biodiversity indicators. This study was conducted in two protected and unprotected areas with an area of ​​90 hectares. In order to harvest vegetation and biodiversity, systematic sampling method was used with the beginning of a random point with a grid size of 150 * 200 meters and a total of 60 samples were collected in two protected and unprotected areas. For harvesting in the tree layer, 400 square meters of sample pieces and for the grass layer, 100 square meters (10 * 10) quadrats were determined and used by the minimum surface method. Values ​​of diversity, uniformity and richness of plant species were obtained and SIV values ​​were calculated for tree, shrub and grass layers. The obtained results showed that the amount of diversity, richness and uniformity in the protected area in grasslands and trees is higher than the unprotected area. The highest SIV value was obtained for hornbeam and winter alder species in the tree layer and the lowest for Oja and Teda pine species. The highest amount of SIV for herbaceous species belonged to the family Asteraceae.

This study aims at assessing the effect of altitude and the most important soil components on vegetation characteristics in the Asalem Watershed basin. For this purpose, 160 0.1 ha circular plots, were established along altitude gradient. Vegetation layers and soil physio-chemical characteristics were measured within sampling plot. The results of vegetation composition in different vegetation layers showed a fluctuation along the altitude gradients. Soil physical characteristics did not indicate specific variation pattern. Whereas, soil organic carbon was increased significantly along altitude (P≤ 0.01). The results of Canonical Correspondence Analysis (CCA) indicated a positive correlation between soil Ph and diameter at breast height (DBH) of Diospyros lotus, Parrotia persica, Quercus castaneifolia and Sorbus torminalis species. In shrub layer, there was a significant correlation between density of species and environmental factors. The density of Evonymus latifolia and Vaccinium arctostaphylos had a significant relationship with altitude, the percentage of phosphorus and silt, directly. In the herbaceous layer, significant relationship belonged to percentage over of Festuca drymeia, Lathyrus laxiflorus, Potentilla micrantha, Veronica persica and Viola odorata with altitude and percentage of organic carbon. According to the results, it can be noted that the altitude is the main factor in the distribution pattern of vegetation composition in the study area. Changes in environmental conditions along the gradient, are effective on the quality and quantity of soil organic matter through vegetation changes which provide favorable conditions for the establishment of a specific plant species

This study aimed to investigate the effect of altitude on diversity and Species Importance Value (SIV) of herbaceous species in forests of Kabirkouh, Ilam province. For this purpose, an area of 300 ha was chosen from these forests. The area was divided in to three altitudinal classes (700-1000, 1000-1300, 1300-1600 m a.s.l.). 63 sampling plots were taken in the studied area using the minimal area method. In order to estimate herbaceous cover, the percentage of herbaceous species were recorded according to Van der Marel criterion. Species richness index (R=S), the Shannon- Wiener’s diversity and the Smith- Wilson’s evenness indices were used to calculate the herbaceous species diversity. Determination of correlation between biodiversity indices and altitude was done using Pearson’s correlation coefficient. The results of this study showed that the altitude had a significant effect on the diversity and richness of herbaceous species, and there was a negative correlation between these indices and altitude. The highest species diversity and richness index were in the middle altitudinal class. The results also indicated that altitude had no significant effect on the evenness of herbaceous species. In addition, the shape of the curve of Species Importance Value of herbaceous species in all three altitudinal classes was a lognormal distribution.

Spatial patterns of trees and their interactions specifically reflect mortality, gap creation, resource use, and also determine population dynamics such as seed dispersal, understory development, initial survival and establishment, growth, and competition. In this study, three one-hectare sample plots in the three stages of early development, maturity and decay were selected in an untouched mixed beech forest in order to consider competition of trees from different height stories along developmental stages and all trees with a diameter at breast height (DBH) larger than 7.5 cm by species were measured based on chest diameter, height and determination of cartesian coordinates using distance-azimuth method. Then, these stems data were first divided into three groups (lower, middle and upper stories) depending on their location in the vertical strata. The spatial patterns and spatial associations were analyzed among different tree height classes using univariate and bivariate Ripley’s K-function. Results showed that spatial pattern varied with canopy strata and scales in different development stages. Positively spatial associations of Fagus orientalis at upper and lower stories in initial and optimal staged and also among F. orientalis at upper and middle stories in decay stages influenced by shade-tolerance characteristics, seed dispersal limitation and the role of larger nurse trees as a shelter of small trees. Competition for resources was observed between Fagus orientalis at the middle story and Carpinus betulus at upper story in the all development stages. Recognizing spatial pattern and natural events guided by nature over time are necessary to carry out targeted forestry operations and In proportion to the evolutionary stages of forest stands.

Quercus macranthera is extended in forest areas of the upper elevations in north of Iran and play an effective role in conserving soil and water infiltration. The biggest problem in the regions is livestock grazing and forest dwellers. The aim of this study was to study effects of protection on the quantity and quality characteristics of Persian oak(Quercus macranthera) in Roudbar forests of Guilan province.

In total, 40 plots of 1000 m2 (20 plots in protected area and 20 plots in unprotected area) were collected using randomized systematic method and grid sampling of 100 × 100 m. In each plot, number and type of tree and shrub species, diameter in breast height, height, crown position and trunk quality were measured. Also, a micro-plot of 100m2 in center of plots was used to calculate regeneration.

The results showed that density of trees, the average of diameter at breast height, total basal area, plant height, volume and regeneration were significantly were higher in protected than unprotected areas. There were no differences in other tree species. Density of barberry (Berberis vulgaris L.), Crataegus microphylla K. Koch and cherry plum (Prunus divaricata) were significantly higher in unprotected than protected area. Also, quality of crown and trunk were better in protected than unprotected area. Study of diameter classes in structure triangle showed that protected area located in irregular section and degraded area located in small-medium diameter section.

As Quercus macranthera trees play an important role in upper parts of the forest, maintaining this valuable species and continuity programs of livestock and human emersion is essential.

This study was carried out in Asalem Watershed basin NO.7 In order to determine relationship between the percentages of herbaceous cover with environmental factors. 17 linear transects with about 1600 m elevational gradient and 3000 m horizontal distance were selected. For this purpose, 46 plots of 400 m2 were selected by field survey within 200 m intervals along the elevational gradient. Within each plot, three quadrates (5 × 5 m) on the diagonal line were chosen and internal (1 × 1 m) quadrates were used for investigation herbaceous cover. Independent variables including aspect, slope and dependent variables including abundance and percentage of cover were recorded by using Domin’s criterion in each plot. In addition, soil samples were taken from three soil cores at each plot. The most effective factors on herbaceous cover percentage were obtained using Canonical Correspondence Analysis and multiple regression method. Results indicated that Soil characteristics showed the highest impact on percentage of herbaceous cover and the most important factors were soil organic matter, phosphorus and Potachium content. The cover percentage in the species belonging to the Poaceae increased with increasing percentage of silt.

It is important to be aware of the spatial dependence structure of different soil properties in natural resources to achieve more production and better management. This study aimed to determine the determining factors controlling spatial variations of macronutrient (NPK) by geostatistics. In the present study, 150 surface soil samples were collected from forests of northern Iran and some variables, including nitrogen, phosphorus and potassium were measured. The half-variance was selected to determine the spatial correlation and the best fitted models on half-variance for variables of nitrogen, phosphorus and potassium were spherical. Also, the effective range for these variables was obtained, which was equal to 530/80, 720/20 and 520/80 meters, respectively. Interpolation was performed using traditional Ordinary Kriging (OK), the inverse distance weighting (IDW) and radial basis function (RBF) techniques using ARC GIS and GS+ software and the accuracy of the distribution map of these variables was calculated using mean absolute error (MAE) and Root Mean Square Error (RMSE). According to the results, the OK technique for the variables of nitrogen, phosphorus and potassium variables was considered as the best interpolation method for estimating the variables in areas where sampling was not performed, because it had the highest accuracy and lowest error.

Plant distribution in forest ecosystems is not accidental and influenced by various factors. This study was done to investigate the structure, physiognomy and site requirements of Mediterranean cypress species (Cupressus sempervirens var. horizontalis) in order to achieve the basic structure, physiognomy and site requirements information of this species relative to soil and physiographic factors in Eshkevar, Rahimabad, Rudsar. For this purpose, 25 circular plots, each one with 1000-m2, were located according to random sampling. In each plot, type of tree and shrub species were designated; then, diameter at breast height (DBH) of trees more than 7.5 cm was measured. In each plot, soil sample were taken from 0 to 10 cm depth. The results indicated that stand structure was uneven-aged. Physiognomy studies showed that in tree, shrub, and herbaceous layers, broad- leaved and need-leaved trees, deciduous shrubs, and forbs were, respectively, dominance life forms. Between environmental factors, aspect and soil textures were effective on diameter, height and individual number of Mediterranean cypress. Number of species had a positive and negative correlation with sand percentage and aspect, respectively.

Studying the spatial pattern in plant communities is necessary for understanding the many issues in forest ecology and management. The purpose of this study is investigating the effect of recreation on Spatial patterns of trees in Zagros oak forests. Sampling methods were fixedarea plots and T-square methods. In each region, there are 40 sample plots and 40 sampling points were taken to measure the distances in the distance method in each region. To quantify and analyze the distribution patterns in the sample method, Green, Morissita and Standardized Morisita indicators were used and The Hopkins, Eberhardt, Heinz, C, Johnson and Zimmer indicators were used in the distance methods. C, Hopkins and Heinz indicators showed a clumped pattern in the area. But the Johnson Zaimer and Eberhart indicators showed a regular pattern in the control area. The results showed that among the Sample plot indicators the Morissita and Morissita standardized indicators expressed a clumped pattern in the recreational and the control area, and the Green indicator showed a regular pattern in the recreational area and the control area. The values obtained from the distance indicators showed that the degradation in the recreational area caused a change in the spatial pattern and the spatial pattern in the recreational area was changing so that most indicators in this area showed a regular pattern. Among the distance indicators used, C and Hines indicators and among the sample method, the Green indicator showed these differences well and the species of the two regions were identified suitable to describe the spatial pattern.

In most ecosystems, the disturbance is an important agent of variation in community structure and composition. Determining the diversity and composition of the soil seed bank is essential for designing the conservation and restoration programs. In this study, the characteristics of soil seed banks were examined in different periods after a fire (One-year, five-year, ten-year of fire and control) in Kuhdasht city. In each area, 40 samples were collected from 0 to 20 cm depth. A 20 × 20 cm metal frame was used to collect soil seed bank samples. After the chilling treatment, soil samples were transferred and spread in the greenhouse. The results showed significant differences between similarity indices in the soil seed bank in four regions. The highest similarity of the soil seed bank and above-ground vegetation was observed in the control area and then 10-year in the fire area. The result of DCA showed that different fire severities and their effects on site conditions have been reflected clearly in the composition of the soil seed bank. Also, results showed the soil seed bank density differed significantly between four regions. The species with the highest soil seed bank density in the 10-year, 5-year, and one-year area were more and hemicryptophyte. The Shannon diversity, Margalef richness, and evenness indices differed significantly among the four regions. According to the results, changes in habitat after the fire in the short term are evident in soil seed bank composition and these changes are recovered over time.

The diameter and height of trees are essential variables for biomass prediction, carbon storage, and forest stand development. Compared with height, measuring the diameter of trees more convenient and is associated with lower cost and error. In this study, nonlinear models were used to estimate height of lime trees in the Shafaroud forests of Guilan. Lime (Tilia begonifolia Stev.) trees are distributed from low to high altitude of 1800 m in Shafaroud forests and have an important role in preserving its natural composition and stand structure. A systematic random sampling method within a 200 × 200-meter network was applied for data collection. Data were collected from 48 circular sample plots with 1000 m2 at altitudes from 500 to 950 m (parcels no. 29 and 30 in 16th compartment) as well as from 50-500 m (parcels no. 14 and 18 in 17th compartment). Modeling was performed with 12 commonly used nonlinear models and multilayer perceptron neural networks with the Levenberg-Marquardt algorithm, which has the advantage to accommodate the complex nonlinear relationships between input and output data. Performance criteria including root mean square error (RMSE), adjusted R2, AIC, and MAD were used to compare the results. Results showed the highest performances of Burkhart-Strub (1974) in mid-altitude and Stoffels-Van Soeset (1953) models in low-altitude forests, while artificial neural network (ANN) returned the highest accuracy and performance in both sites. It decreased the RMSE by 5.54% in sub-mountain and 7.35% in low-land forests compared to the best applied nonlinear models. Although the suggested nonlinear models were accurate enough for the study site, the ANN method is preferred for its higher accuracy.

One of the most important factors for determining the volume of trees is selection of an appropriate form factor. This study determined the most appropriate form factor formula and modeling the actual form factor in the Caspian region of northern Iran, Guilan’s forests. Totally, 150 beech (Fagus orientalis) trees were measured. Three coefficients of natural, artificial, and Hohenadel were compared with the actual form factor using pair-wise comparison test. Several nonlinear equations including logistics, Chapman-Richard, and exponential functions were used for modeling the form factor of beech trees. These functions were evaluated in terms of coefficient of determination (R2), paired t test, and accuracy statistics of ME, Root Mean Square Error (RMSE), MEr and RMSEr. The result showed that there were significant differences between the actual form factor and   the each mentioned coefficients. None of the models presented high R2 values. Accuracy statistics showed that exponential and logistic models can be usefully applied for estimation of the actual form factor coefficient. Also the results of t-test showed that there was no significant difference between of actual and estimated means of form factor derived from the logistic model. Therefore, logistic model was selected as the best for the estimating form factor of beech trees in Guilan’s forests of the Caspian region.

The purpose of this study was to evaluate the effect of road distance and age on roadside vegetation cover on  Nav district forest roads in the west of Guilan province.Therfore required data in 240 Systematic random plots on linear transect in two road age classes were collected. Percentages of vegetation were calculated using Brown Blanket combination scales. Then, the values ​​of richness, evenness, Shannon-Wiener, and Simpson indices were calculated for each age class of road. Relative importance index was used to determine the distribution of species abundance. The results showed that the relative importance and presence of dominant tree species in the newly constructed roads were higher than the old ones. In both age groups, the relative importance of beech (Fagus orientalis), hornbeam (Carpinus betulus) and alder (Alnus subcordata) saplings was higher than other species. Also, the relative importance of tree species decreased with increasing distance from forest road. Also at different distances of the road, beech and maple regeneration were the most frequent. The highest values of diversity and richness were observed at 0-30 m distance from the road and its value was significantly different from other distances.

This study was carried out in the oriental beech communities in order to investigate the natural regeneration and assessment of radial growth trend from 1960 to 2016. In each area, 50 1000-m2 circular plots were established based on a random-systematic method. Regeneration was sampled on two concentric circles with an area of 20 and 10 m2 of the sample plot center (for seedling and sapling, respectively). Then, 160 core samples were taken from selective trees by increment. The results of harvested stand indicated that natural and human disturbances regimes lead to change in the diameter distribution, age distribution, radial growth pattern and establishment of tree's regeneration. In the unharvestedarea, sapling of F.orientalis and seedling of Carpinus betulus and Acer velutinum had the highest density. Whereas, the seedlings of F.orientalis and C.betulus were dominate in the harvested stand. During the studied period, 324 tree species were established in the unharvested area and the highest frequency of tree recruitment was belonged to 1970-1980 decades. However, in the harvested stand, 262 tree species were established and the greatest frequency was recoreded from 1960 to 1970 years. The radial growth of trees in the harvested area showed the higher variations during the studied period and the highest frequency of release events was belonged to moderate releases. Therefore, this stand should be managed in order to return their historical composition and structure, maintaining natural regeneration and the optimal development of stand for future.

Information about the spatial patterns of soil biodiversity and understanding the effects of biodiversity on ecosystem processes are limited. This study was conducted to determine whether biodiversity of soil macrofauna features demonstrate spatial patterns in the Populus deltoides plantation in north of Iran. 150 soil samples were taken using a grid sample of 40 × 40 m. Soil macrofaunawere sampled by digging and hand sorting two 50 × 50 cm areas into a depth of 20 cm in each treatment.Abundance (the number of macrofauna) diversity (Shannon-Weiner index), richness (Menhinick index) and evenness (Smith–Wilson index) were calculated using geostatistics (variogram) in order to describe and quantify the spatial continuity. Some soil chemical and physical properties were determined. The variograms of variable revealed the presence of spatial autocorrelation. The range of influence was 710.9 m for abundance, 650.3 m for diversity, 720.90 m for richness and 410.9 m for evenness. The kriging maps indicated that the soil macrofauna have spatial variability. Moreover, the spatial pattern of macrofauna biomass is similar to the pattern of clay and pH of soil.

In order to comparing the regeneration and diversity in natural and created gaps, all of the gaps in two compartments in Asalem forests were identified and divided into three categories: small gaps (2), medium gaps (200-500 m2), and large gaps (>500 m2). Seven plots with an area of 4m2 (2m×2m) were taken in each gap. The number of individuals of tree seedlings and saplings were recorded and coverage percent of herbaceous species were estimated in each plot based on extended Braun - Blanquet cover - abundance scale. In addition to counting the number of species, diversity indices including Simpson (1-D) and Shannon-Wiener (H') and Smith- Wilson’s evenness indices were calculated. The Kolomogrov-Smirnov test was used to study the normality of data and then one-way ANOVA test was performed using SAS software. Totally 38 natural and 30 created gaps were identified. The results revealed that mean of each gap size was 371 m2. There were no significant difference between the size of natural and created gaps but the number and total regeneration were significant differences among natural and created gaps. The least abundance of seedlings were obtained in the small gaps. Also diversity indices had maximum in the created gaps.

Zagros forests are one of the important natural ecosystems in Iran with high plant diversity and variety of plant communities. In recent decades, fire events have frequently occurred in some of these ecosystems. The purpose of this research is to investigate the composition and diversity of herbaceous species after nine years of fire occurrence in the forests of Zagros in western Iran. For this purpose in 2015, an area of 40 ha that had burned in 2006 was selected and compared with the unburned area (control area). In both areas, 80 plots were selected. The optimal size of plots was determined based on Whittaker's nested plot sampling and minimal area method. Then, vegetation cover percent of each herbaceous species was estimated according to Van der Marel criterion in each plot. The results showed that the fire reduced the diversity, evenness and richness indices, but this decrease was not significant between Shannon-Wiener (P= 0.57) and species density index (P= 0.06). Species Avena fatua with 21.51 and 18.56% had the highest coverage in the burned and control areas, respectively. In addition, the average of herbaceous percent cover was significantly higher in the burned area (P<0.05). Also, Fabaceae, Asteraceae and Poaceae families were the most important families in both areas. The overall results of this study revealed that many species are able to restore their primary conditions over time.

Fauna of cheyletid mites (Cheyletidae) in central part of Guilan Province, northern Iran, was studied during 2016-2017. The abundance and dominant indices of collected species were also evaluated in five habitats including stored rice products, decayed plant material, plant leaf, soil and livestock and poultry manure. In this research, totally 19 species belong to 8 genera and 5 tribes were collected and identified. An identification key to genera and species of cheyletid mites in Guilan Province is provided. Stored rice products with 73.02% has the highest abundance of mites among habitats, subsequently, decayed plant material (12.82%), livestock and poultry manure (6.1%), and leaf (4.41%) were in second to fourth ranks. The lowest relative abundance was observed in soil (3.64%). In comparison the frequency of species in different habitats, the highest percentage of abundance in livestock and poultry manure was due to Cheyletus malaccensis Oudemans (59.7%). Cheyletus malaccensis, Cheyletus carnifex Zachvatkin and Cheyletus eruditus (Schrank) with 41.77%, 23.59% and 19.72%, abundance respectively, have the most relative abundance among the total collected species. Based on the Simpson dominance index, the highest species dominance was due to soil (lowest diversity) and the lowest dominance was in livestock and poultry manure (the most diversity). In the Burger-Parker dominance method based on species abundance, Cheyletus malaccensis had the highest dominance in livestock and poultry manure and the lowest dominance in the soil.

This study was carried out to investigate the effect of different plantations on the activity of soil organisms, biodiversity indices and their relationships with the measured soil physical and chemical characteristics. Sampling of soil, soil organisms and microbial indicates were done in plantation of Populus deltoides, Pinus taeda and natural forest stand by random systematic method. In each mentioned tree stands, 40 places were selected and soil samples were taken from a depth of 0-20 cm.
The results showed that the highest microbial respiration, microbial biomass carbon, microbial biomass nitrogen and bacteria were observed in Populus deltoides and natural forests. Two indicators of metabolic and microbial also showed significant differences among the stands. The result of Pearson correlation between microbial indicators and different soil properties showed that there is a positive and significant correlation between these indicators and organic carbon and total nitrogen.
On the base of this study, it is declared that the variations of soil qualities properties and the diversity indices are proportional to the properties and the forest site productivity. Population of macrofauna, as an indicator of the site productivity, will be suitable indicators for evaluation of the forest management roles related to ecosystem conservation and permanency. Based on the results, Populus deltoides compared to the other forest stands showed favorable conditions to produce more organic matter and microbial respiration.