جستجوی مقالات مرتبط با کلیدواژه "diversity" در نشریات گروه "جنگلداری"

Structure of forest ecosystems undergoes changes in the temporal and spatial scale that this changes cause development. Development process is very slow and takes place in long term in this unites. For evaluation of this changes are used density, canopy and mixing amount. Structural attributes, show the ecological diversity and sustainability of forest ecosystems well. We conducted this study to compare changes in the structural attributes of density and canopy with diversity of tree species between different stories, as well the relationship these variables with diversity indices, between two periods of inventory in fixed location and natural environment where external factors have the least proportion in stand development.

Permanent sample plot with an area of 16 ha is located at 770-920 elevation and Northwest and west directions in 32 compartment, district one Shast Kalateh forest. Inventory was carried out using 100 % sampling method with 1 ha sample plot. Differences from 2003 to 2023 quantitative attributes of density, canopy and biodiversity indices were measured with standard method and compared through ANOVA in different stories.

The density of trees in the investigated plot reduced from 306.31 to 275.44 trees per hectare in 2003 and 2023. Only, Beech (Fagus orientalis Lipsky) species increased in density during this period. The highest frequency of tree individual belonged to under story in 2003, but in 2023, it was transferred to middle story. The average crown coverage percentage reduced from 86% to 70%. The highest amount of canopy percentage assigned to middle and upper stories. The average of Shannon's heterogeneity in 2003 in three story was (1.32, 1.29, 0.72) and in 2023 (0.49, 0.53, 0.58) respectively. The Shannon Wiener diversity index provided a better judgment of the species diversity in the investigated plot than other indices.

The investigated plot is a Mixed beech stand in which Beech shade tolerance species is dominant. Mixing more tree species while increasing diversity at different levels will bring stability of forest ecosystems. The results of this research showed that the indices of species diversity are only one of the methods of interpretation and evaluation of forest ecosystems and other characteristics should also be paid attention to. The periodic monitoring of this indices correctly shows changes trend of forest ecosystem. The results of used indices can be basis of evaluation and comparison with similar forest. Keywords: Structure dynamics, Diversity, Tree strata, Mixed beech stand

The relationship between soil invertebrates and silvicultural practices in the oriental beech forests (Fagus orientalis Lipsky), a widespread forest tree in the Hyrcanian region, is not fully understood. The diversity of soil invertebrates is a crucial variable in the ecological evaluation of managed forests. Therefore, this study aims to assess the impacts of silvicultural practices on soil invertebrates, which is essential for sustainable forest management. The soil invertebrates studied included Earthworms, Winged insects, Aranea, Pseudoscorpions, Collembola, Protura, Diplura, Diplopoda, Chilopoda, Symphyla, Pauropoda, and Isopoda. The objective was to compare the abundance and diversity of soil invertebrates between two managed (No. 8) and unmanaged (No. 36) compartments in the Haftkhal forests of Neka city, Mazandaran province.

Soil sampling was conducted in 131 ha of the studied forests using a regular random method with grid dimensions of 150 × 200 m. A cylindrical device with a cross-sectional area of 81 cm² and a depth of 10 cm was used. Twenty and thirty sampling plots were obtained in managed (No. 8) and unmanaged (No. 36) compartments, respectively. The average abundance and the average number of soil invertebrate groups per square meter were determined. Additionally, Shannon-Wiener and Simpson Indices were used to calculate soil invertebrates’ diversity, while Margalef and Sheldon indices were used to determine species richness and evenness, respectively.

The results showed that the averages of total abundance and the number of soil invertebrate groups per square meter in the managed forest (117278.70 and 7.31) had a slight decrease compared to the unmanaged forest (120167.77 and 7.62). Also, the diversity averages based on Shannon-Wiener and Simpson indices, along with the Margalef richness of soil invertebrates in the managed forest (1.890, 0.834, and 1.770), had a slight decrease compared to the unmanaged forest (1.928, 0.840, and 1.862). On the other hand, the average Sheldon evenness of soil invertebrates in the managed forest (0.935) had a slight increase compared to the unmanaged forest (0.924). Overall, road construction and exploitation operations during the two periods of the forestry plan implementation created scattered changes in the managed compartment, leading to a slight decrease in the abundance, richness, and diversity of soil invertebrates. However, the values of all the investigated variables between managed and unmanaged forests were not statistically significant (p=0.05).

This research demonstrated that forest management, utilizing the forestry method of uneven-aged mixed forest and the silviculture system of single-selection, has not significantly reduced the abundance and diversity indices of soil invertebrates in the managed forest compared to the unmanaged forest.

This research was conducted in 2020 in order to investigating the species diversity and abundance of oribatid mites in the oak and hornbeam forests of Arasbaran (Ahar and Kaleibar) in East Azerbaijan Province. Soil sampling was carried out in May and June. Oribatid mites present in soil samples were separated using Berlese funnels and clarified in relative solution, followed by preparation of microscope slides. After identification, counting, diversity and evenness indices (Shannon and Simpson), as well as species richness were calculated using Ecological Methodology 6.0 software. In general, 29 species of Oribatid mites from 27 genera and 23 families were identified in this study: Cosmochthonius lanatus Michael, Sphaerochthonius splendidus Berlese, Steganacarus (Tropacarus) carinatus Koch, Papillacarus pseudoaciculatus Mahunka, Rhysotritia ardua Koch, Nothrus biciliatus Koch, Hermanniella septentrionalis Berlese, Plesiodamaeus ornatus Pérez-Íñígo, Belba sp., Xenillus setosus Grobler, Ozman & Cobanoglu, Fosseremus quadripertitus Grandjean, Rhinoppia obsoleta Paoli, Ramusella (Ramusella) puertomonttensis Hammer, Ramusella (R.) sengbuschi Tokyoensis, Ramusella (R.) sengbuschi Str., Graptoppia (G.) sundensis acuta Ayyildiz, Rectoppia sp., Suctobelella sp., Austrocarabodes (Austrocarabodes) foliaceisetus Murvanidze & Weigmann, Tectocepheus velaus Michael, Eupelops acromios Haman, Berlesezetes aegypticus Balogh & Mahunka, Oribatula (O.) tibialis allifera Subías, Protoribates (P.) paracapucinus Mahunka, Scheloribates fimbriatus Thor., Ceratozetes conjunctus Mihelčič, Punctoribates angulatus Bayartogtokh, Grobler & Cobanoglu, Galumna sp., Pilogalumna sp. The highest abundance of mites in Ahar and Kaleibar belonged to Scheloribtes fimbriatus and Oribaiula tibilis, respectively. The calculated species diversity indices in the Kaleibar region during June were higher than those in May. The diversity and species richness of oribatid mites were higher in Kaleibar with oak vegetation, which could be due to the higher humidity and acidity of the soil compared to Ahar.

Iron wood (Parrotia caspica (D.C) C.A. Mayer) is one of the endemic tree species of Iran that is widely distributed in Hyrcanian forests from west to east. Due to the fact that climatic factors in the northern forests are variable, the relationship between the ecological conditions of the habitat and the leaf stomata of Iron wood tree species was investigated in this study. For this purpose, leaves of 10 populations were collected from three provinces of Guilan, Mazandaran and Golestan and the morphological characteristics of their surface, density, length and width of the stomata were investigated. Also, habitat characteristics of diameter equal to tree trunk, altitude of habitat, temperature and rainfall were used for climate modeling. The results showed that with a 99% probability there was a significant difference between the stomata characteristics of Iron wood trees in different habitats (P<0.001). The trend of stomata density changes from west to east of northern forests was decreased, but stomata area increased from west to east. The predicted model showed that altitude and temperature had a significant effect on stomatal density (P<0.001). Temperature and rainfall had a significant effect on the stomata area (P<0.001) but the effect of altitude and diameter at breast height on the stomata area was not significant. In general, it can be said that the characteristics of the stomata are closely related to the climate conditions prevailing in the habitat.

Endophytic fungi are fungi that are present in plant tissue at the time of sampling without obvious symptoms. There are several reports that the use of endophytic fungi improves grain yield, increases cold and drought tolerance, resistance to plant pathogens and herbivorous insects. Therefore, these fungi can be used as a biocontrol agent in the protection of crops. Endophytic fungi are a rich source of active metabolites that have the potential to be used in medicine, agriculture, and industry, so this study was conducted to isolate endophytic fungi from hornbeam trees and their morphological and molecular identification from the forests of Sari.

In this study, to identify endophytic fungi from healthy branches of hornbeam trees during autumn 2019 and summer and autumn 2020 of the forests of Sari city were sampled. In the laboratory, each branch sample was kept for 24 months at 24 ° C and continuous darkness after disinfection and culture on PDA medium. Morphological features and sequencing of the ITS region were performed to confirm the morphological identification and sequencing of the relevant dendrogram using version 7.1 of Bioedit software.

In this study, 9 genera and species were identified. Fungal species includ:Alternaria alternata (OM117707), Aspergillus flavus (OM488258), Botryosphaeria dothidea (OM141395), Diaporthe eres (OM131770), Fusarium acuminatum(OM131729),Fusarium sambucinum (OM142129),Mucor fragilis (OM017151), Neofusicuccum parvum (OM017148), Fulvia fulva (OM124921).

In general, the aim of this research was to identify the fungal endophytes of Beech trees based on morphological and molecular data from the forests of Mahdasht, Tabaghdeh, Darabkala and Imamzadeh Zaid Sari located in Mazandaran province.

Obtaining information and identifying the changes and dynamics of forest ecosystems in different developmental stages is necessary for optimal management, restoration and improvement of forests. The aim of  This research  was to investigate the effect of different development stages of the stand on tree regeneration and understory species in the mixed hornbeam stand in spring and summer (due to the beginning of vegetative activities until the optimal vegetative stage of herbaceous plants) in the forestry plan of Gorgan Shasat-Kalate district two was done.

In order to investigate development stages, after forest surveying, three rectangular half-hectare sample plots with dimensions of 50 x 100 meter for each development stage based on the characteristics provided by Leibundgut and Korpel in the field of the structure pattern of development stages and phases in natural forests were used. In order to study and investigate the vegetation cover, five small sample plots (20x20 meters), one of them in the center and four other in the four corners. In each sample plot, the percentage of herbaceous species cover and the tree regeneration frequency were recorded. To investigate and compare diversity in different development stages, use the diversity indices of Simpson and Shannon-Wiener, and to calculate the richness, use the richness indices of Margalf and Manhinik, and for evenness, use the evenness indices of Smith-Wilson and Evenness in PAST and R software (package Adiv software and specieseve function( were used.

The results showed that the number of plant species in the degradation stage is more than the initial and optimal stages. Diversity indices of understory species and tree regeneration species showed that the diversity of Shannon and Simpson in the two seasons of spring and summer in the optimal stage was lower than the initial and degradation stages. Also, Smith-Wilson and Evenness indices had the highest values in both spring and summer in the optimal stage. The highest value of the Menhinic richness index of understory species was determined in the optimal stage in the spring season, while no significant difference was observed between the different stages in the summer season. The highest value of Margalef richness index of tree species regeneration in both seasons was also observed in the degradation stage.

Based on the results of the present research, it can be stated that different development stages have an effect on the diversity of herbaceous species and forest regeneration. Therefore, there are significant implications of sustainable management on the vegetation layer, which should be considered in future of forest management strategies.

Euproctis chrysorrhoea L. is the key pests of Arasbaran forests and has very high distribution. This research was conducted in order to investigating species diversity and richness of the arthropods related to wintering larvae of pest in eight regions of Ahar and Horand in East Azarbaijan in 2019. Number of 20 oak trees were selected in each area and 10 nests of wintering larvae were collected from each tree and transferred to the laboratory. Isolation of arthropods inside larval nests was done in the laboratory and species richness indices, Shannon and Simpson diversity of them at different elevation classes were also calculated. In this research, the number of seven species of arthropods on the overwintering larvae of E. chrysorrhoea were collected and identified as follows: Brachymeria intermedia Nees, Monodontomerus aerus Walker, Pimpla turionellae L., Meteorus obsoletus Wesmael, Telenemus sp., Tachina praeceps Meigen and Thomisas sp. The highest number of arthropods (six species) was observed in Niagh area in Horand. The highest frequency was belong to Telenemus sp. Diversity and species richness of arthropods of E. chrysorrhoea was less in different regions of Ahar than Horand. So that the highest and lowest values of Shannon's diversity index with values of 2.56 and 1.04, as well as the highest and lowest values of Simpson index with values of 0.76 and 0.31, respectively, were recorded in Niagh in Horand and Goravan in Ahar. Results showed that the height above sea level did not affect diversity indices of arthropods related to wintering larvae.

Euphrat Poplar (Populus euphratica Olive.) is a native tree of Iran with high adaptation to the ecological conditions of arid and desert areas. In this research, the plant cuttings were collected from main habitats including Masoumiyah, Hamidiyeh, Maranjab and Manjil. Traits such as survival and establishment percentage, diameter and height growth and the rate of disease and pest damage were measured. The results of split plot at the time and place of vegetative indices of seedlings showed significant effects of the studied factors on the diameter and height of seedlings (p≤0.01). In non-saline, Semi-salineand saline experimental farms, the population of Manjil had the highest and Marnjab the lowest survival. The populations of Manjil and Masoumiyah had the highest height in the non-saline farm. Vegetation indices in non-saline farms had higher values than semi-saline and saline farms. In the semi-saline farm, the population of Manjil and Masoumiyah had the largest and Marnjab and Hamidiyeh had the smallest collar diameters. Although in the saline farm, the populations of Masoumiyah and Manjil had the highest seedling height, but they were not significantly different from the other two populations. In the saline farm, in terms of seedling diameter, the populations of Masoumiyah and Manjil were superior to the others. The overall results showed that due to the higher genetic potential in Manjil habitat and suitable conditions of mother trees in terms of soil and especially water availability in Manjil and Masoumiyah habitats, survival and diameter and of height cutting are higher in these populations.

Due to rapid population growth and increasing demand for forest resources, large areas of forest have been subjected to different degrees of degradation, and this degradation is increasing at an alarming rate. Large areas of forest have been varied by various degrees of degradation, and this degradation is increasing with an alarming rate due to rapid population growth and increasing demand for forest resources. Only 15 percent of the world's forests are undegraded, 20 percent have been destroyed and 28 percent have been deforested. Forest degradation is a global phenomenon that destroy10.6 million hectares of the world's forests each year. Therefore, studies focus on the effects of forest degradation impacts on the structure and composition of forests around the world. The goal of this study was to compare the structure of oak-hornbeam stands in different degradation intensities in Arasbaran forest.

The distance method was used to calculate the structural diversity index in Arasbaran forests, using three indicators, including uniform angle, tree diameter differentiation, and mingling indices. Within the study area with the different intensity of human interventions, three one-hectare sampling areas were selected. In order to select the study points in the regular systematic way 25 *25 m grid was laid out and the nearest tree to the intersection point of gird as reference tree was selected and measured with the four nearest neighbor trees. the diameter at the breast height (DBH), distance, and angle between trees in structural groups were measured.

The results of calculating the uniform angle index showed a change in the distribution pattern of stands due to the increase in the intensity of destruction from random to clump and uniform distribution. The diameter diffrentation index of trees showed that the value of this index was the lowest (0.12) in the moderate and was the highest (0.38) in the severe degradation intensity. The results of the study of the mingling species index showed that the highest value of this index was in the low degradation intensity (0.61) and the lowest value was in the moderate degradation intensity (0.08). Statistical analysis showed a significant difference (p≤ 0.05) between these indices in all stands. Calculation of the structural diversity index also showed that the highest structural diversity was in the stands with low degradation intensity (0.5) and the stands under medium degradation intensity had the lowest amount of structural diversity index (0.14).

Planning to reduce the human interference should be prioritized considering the effects of human degradation on the structure of the Arasbaran forest.

the intermediate disturbance hypothesis predicts that communities with intermediate disturbance rates will have the greatest species diversity compared to communities with high and low frequency disturbances. Therefore, a recently disturbed area should be dominated by early-colonizing species or ruderal species. A late successional area is predicted to be dominated by strong competitors and a mid-successional area by a mixture of the tow. Composition of forest community in different successional stages is important as one of the key management issues. This study was conducted to investigate the effects of successional stages on density and composition of bird species and to test the intermediate disturbance hypothesis.

The total numbers of 60 Sampling units were selected and were evenly assigned into 3 treatments. 20 samples were allocated for each of the three treatments including clear cutting, single tree selection logging, and virgin compartments equivalent to the early stage of succession, intermediate stage of succession, and climax stage of succession, respectively. Environmental variables and birds were detected within 60 circle sampling plots with 25m radius. The number of tree species, basal area, height of trees, number of snags, density of grass cover, canopy cover, and litter depth were recorded at each sampling plot. Birds were recorded using point-count method.

Forest structure variables including tree density, Shannon-Wiener diversity index, Camargo evenness index, species richness, tree basal area, density of canopy cover, the number of snags, and the number of trees with more than 20 m in height had significant differences among different successional stages. Moreover, bird community structure including Shanon-Wiener diversity index, Camargo evenness index, and richness index had significant differences among different successional stages. In the period of the study, a total of 24 bird species were recorded. Jay and Chaffinch had the highest abundance in the early successional stage; meanwhile, Black Woodpecker and Coal Tit were the most abundant in the mid successional stage. The Great Spotted Woodpecker, Wren, and Nuthatch were the most prevalent bird species at the mature forest.

bird and tree diversity and richness followed the predictions of the intermediate disturbance hypothesis, being highest in the mid successional plot.

The aim of this study was to compare the richness, diversity, and evenness of soil macrofauna and the factors affecting it during the growing and dormant seasons in Amygdlus scoparia Spach stand in the protected area of Geno located in Hormozgan province, Iran. After the selection of a half-hectare stand of Amygdalus scoparia in the Geno protected area, 10 soil samples were randomly collected in the depth of 15 cm, under the crown of trees in growing and dormant seasons in order to measure physiochemical characteristics and identify soil macrofauna and their relations. After macrofauna separation, samples were transferred to the laboratory for physiochemical analysis. All variables were compared across two seasons using T-Test analysis (p <0.05) and the correlation of variables was analyzed using Pearson correlation (p <0.01). The results showed that all soil properties (nitrogen, carbon, phosphorus, and temperature) except electrical conduction and soil acidity in the growing season were significantly higher than those in dormant season. The frequency and biomass of macrofauna in the growing season were 1060 in m2 and 5.9 mg.m-2, respectively, comapred to 90 in m2 and 0.7 mg.m-2 obtained for dormant seasons. Further, the indices of Margalef, Menhinick, Simpson, Shannon and Waever, and evenness Pielou and Hill in growing season (2.55, 2.15, 0.79, 1.77, 0.89, and 0.93) were significantly higher than those in dormant season (0.23, 0.53, 0.09, 0.13, 0.49, and 0.19, respectively). Soil macrofauna frequency along with biodiversity, richness, and Pielou evenness indices showed positive and significant correlations with organic carbon, phosphorus, nitrogen and soil temperature.

In recent years the protection of biodiversity became an important goal in forest management and caused some conservative management approaches such as creating managed areas or areas in which no management has been implemented. In the past decade habitat trees came under focus. Micro-habitats are structures on dead or alive trees in the forest including changes such as wounds and fractures caused by biological process and provide places for forest living organisms. Nowadays the necessity of habitat trees protection has been emphasized in forest management and policy. This study aimed to assess the diversity and frequency of tree micro-habitats in Persian ironwood- hornbeam forest stands at Bahramnia Forestry Plan (Gorgan).

Therefore for assessing the trees’ micro-habitats 4 square sample plots each one with the area of 2500 m2 were selected and allometric characteristics (diameter and height) of all trees with the diameter more than 7.5 cm were recorded. Then according to an instruction the type and abundance of micro-habitats were assess and recorded for all trees. A binocular was used for assessing the micro-habitats located on top of the tree crown and their upper trunk. The habitat value as well as economic value of all trees have been calculated using Integrate+ software. Correlation test was used to assess relationship between occurrence and frequency of micro-habitat with quantitative characteristics of all trees.

The result showed that the studied stand is an uneven-aged stand and Persian-ironwood tree species is the most abundant tree species within it. The hornbeam trees have the highest average diameter and height, as well as the highest diversity and frequency of micro-habitats. The most frequent micro-habitats observed on the trees were EP, GR and CV. The result of correlation test showed a significant relationship between tree diameter and micro-habitats abundance. By increasing in the tree diameter the number of micro-habitats significantly increased.

Totally the results of this study show that there are different kinds of micro-habitats in the studied forest stands. Also the tree diameter is one of the factors that affects micro-habitats’ abundance. Therefore it is of importance to maintain some of the high diameter trees in the forest stand. Understanding the effective factors on occurrence and abundance of the micro-habitats can be an important help in protecting forest biodiversity. Studies on habitat trees in Iran’s forest ecosystems (particularly Hyrcanian Forests) is rather a new issue which can be an effective help for better understanding of the other functions of these ecosystems, especially ecosystem services and increasing biodiversity.

Air dryness and deficiency of moisture are In the wide range of Iran rangelands but with some soil mechanical operations can be increased moisture in certain areas of the pasture. In this study the effect of storing operation of curved pit and its dimensions on developing vegetation and soil of pastures was studied in Reihan plain of Ravar-Kerman province. For this purpose, sampling was done in a random way from a small, medium and a large curved pit and a region between two pits. And in each plot was measured crest cover percentage production and the number of plant bases were defined. we put ten soil profiles and sampling was done from the first 30 cm of soil surface in each area . We analyzed data by using two way ANOVA and Duncan test by SPSS21 software. The results suggested that density, production and vegetation percentage were significantly different in the four study sites (p < 0.05) The largest canpy cover and production was in the large curved pit. According to the uniformity index, the Simpson and Wilson homogeneity index has had a significant difference, based on the Simpson index and the Wilson index the highest evenness is in small curved pit. Soil analyzing results show that the organic matter and organic carbon of the large curved pit soil has had a significant increase. In general, due to the high sensitivity of rangeland ecosystems in arid and semi-arid regions we can increase the vegetation cover, by curved pit in large dimensions

This study was conducted to assess the effect of soil physical and chemical properties on diversity and structure of tree cover in oak forests with an area of 275 hectares in Qamyshlh city of Marivan Kordestan, Iran. For this purpose, a total of 90 samples, each 10 yards, randomly laid out on a regular gird network were selected and in the center of each plot, soil samples were taken at the depth of 0 - 30 cm. Results revealed that the average diameter of trees had a significant positive correlation with phosphorus, potassium, organic matter and carbon to nitrogen ratio in the soil. The results also showed that there is no significant relationship between the most measured soil characteristics and richness, evenness and diversity indicators. However, soil pH with Pirlo and Simpson indexes and phosphorus with Margalef index had a significant negative relationship. Correlation between the percentage of tree species and soil characteristics showed that among the studied species, Q. branti were more sensitive to changes in soil properties compared with other species. However, the analyses of ordination methods showed that there is no direct relationship between species distribution and soil properties. In addition to the soil effects, due to the proximity of the forest land to rural residential areas, it can be said that the most influential factor in shaping the composition, diversity, and structure of Qamyshlh tree species are human factors.

In this study, morphology and pollen grain diversity of eight maple species including Acer negundo, A.palmatum, A.monsspesulanum, A.velutinum, A.cappadocicum, A.campestre, A.tanoide L, A.hyrcanum and a cultivar of A.negundo (A.negundo variegatum) were studied to examine their roles in this genus and to find the diagnostic attributes. The results showed that pollen grains of this genus are tricolpateand are of medium size, often heteropolar with no radial symmetry, and are classified in plicate class. Studying the quantitative traits by using one-way analysis of variance and cluster analysis showed a high inter-specific variations among the traits. In the principal component analysis, the distance of two pollen lengths from each another, the length of the equatorial diameter of the pollen grain, the window environment, and the window area were determined to separate the existing species. In order to test the accuracy of the analysis, the detection analysis was used, which confirmed up to 80% of the results of grouping of each species is based on the pollen attributes.

The study was aimed to assess of the Danish and Swiss methods of thinning in 20 years old plantations of Chestnut leaved Oak (Quercus castaneifolia C. A. Mey.) in terms of quantitative and qualitative characteristics of trees, natural regeneration, plant and soil invertebrate diversity. The study area is located in Neka forests, east of Mazandaran province in the Caspian region. This research was conducted under compeletly randomized block design (CRBD) with three replication and three treatments. Also in each sample plot, 3 microsample plot, each 49 m2 were randomly systematic selected. The quantitative and qualitative parameters of trees were measured in each sample plots by full callipering. In each microsample plot natural regeneration was counted. Also, whole plants were recognized in each microsample plot and their coverage percent were estimated. Moreover, in each microsample plot invertebrates were sampled, using core soil samples (81 cm2 cross section) to the depth of 10 cm. The results of this research has been shown that the tree diameter at breast height, the abundance of quality tree and the number of natural regeneration in the thinned areas was more than the control area. Of course, the positive impact of the Danish method was greater than that of the Swiss method. Also this research has shown the control area created a more favorable situation due to the plant species diversity than the thinning areas. However the positive impact of the Danish method was greater than that of the Swiss method. On the other hand the Swiss thinning area created a more favorable situation due to the soil invertebrates' diversity than the Danish method. Overall this research emphasizes that the thinning operation with moderate intensity in Danish method is better than the Swiss method for forestations.

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.

Forest degradation influences ecosystem sustainability and reduces plant species diversity. Plantations with coniferous trees in degraded ecosystems help the native species to become established and play a major role in preserving and improving plant diversity. This study aims at measuring and comparing the woody species diversity across different age classes of Pinus brutia and Cupressus horizontalis in Ghapan region, East of Golestan. Plantations were classified in the following age classes: <10, 10-20, and 20-30 years old. Then an area of about 5 ha were chosen for every age class and a number of 30 plots (400 m2) were systematic randomly selected. List of woody species and their density in each sample plot were recorded. Number of woody species was calculated using species richness, expected richness, and Margalef indices; diversity was calculated using Simpson and Shannon-Wiener indices; and evenness was calculated using Camargo and Simpson indices. Analysis of variance showed that the effects of species, age classes, and their interaction were significant. Slicing of interaction effect indicated an outstanding difference of richness, diversity, and evenness indices across the different age classes of Pinus brutia plantations. The difference of expected richness and Margalef, Simpson, and Shannon-Wiener indices were not significant across the different age classes of Cupressus horizontalis plantations. But, the increasing of species richness and evenness of Camargo and Simpson indices were significant across the age classes of <10 and 10–20 years old. Also, it was showed that Pinus brutia plantation is more suitable for establishment and development of woody species than Cupressus horizontalis and therefore it is recommended for future plantations at the study region.

This study aimed to determine the efficiency of numerical and parametrical indices to evaluate biodiversity of soil and litter mesofauna in different physiographic positions. Sampling was conducted in three height classes above sea level (low land, middele land and high land) and two aspects (north and south). Also, in each altitude class, three different slope classes (less than 25%, 50-25% and more than 50%) were determined. Three transects of about 100 m were established in each of the slope classes. Three sample points were located along each transect. Around the center of each sample point, a litter layer and a soil sample to a depth of 10 cm speratly were taken. In the laboratory, soil and litter samples were placed inside a Berlese funnel to bring out arthropods mesofauna. The results showed that soil mesufauna Shannon–Wiener's diversity, Pielou's evenness and Margalef's richness indices, were significantly affected by aspect, elevation, sampling depth and their interactions. Along the northern aspect and in the litter layer, the highest Shannon–Wiener's diversity index was observed in middle land and slpoe

Applying of plant and animal diversity as well as natural regeneration are the common methods of assessing the ecological potential of forest stands. The objective of this study was ecological assessment in 20 years old plantations of Chestnut leaved Oak (Quercus castaneifolia C. A. Mey.), Velvet Maple (Acer velutinum Bioss.) and Brutia Pine (Pinus brutia Ten.) in term of quantitative and qualitative characteristics of trees, natural regeneration, plant and soil invertebrates. The study area is located in District 2 of Neka’s lowland forests, east of Mazandaran province. Nine sample plots with 1500 m2 were selected in each plantation. In each sample plot, 3 micro-sample plots, each 49 m2 were selected random-systematically including 27 micro-sample plots for each plantation and overall 81 micro-sample plots in 3 plantations. Study of quantitatively and qualitatively survey of trees (diameter at breast height, height and quality of tree) was performed by a fully inventory in three plantations including 6088 trees. Also all of the plants were recognized in 81 micro-sample plots and their coverage percent were estimated. Diversity indices were calculated by Simpson and Shannon-Wiener indices. Also, richness and evenness were obtained by Margelov and Menhinick indices. Mean analysis of quantitative characteristics was performed by the analysis of one-way variance. Analysis of the quantitative and qualitative characteristics of trees indicated that Brutia Pine plantation with the least density had the highest quantitative and qualitative results followed by Velvet maple and Chestnut leaved oak, respectively. Also the mean number of regeneration per square was higher in the Brutia Pine followed by Velvet maple and Chestnut leaved oak plantation. Shannon-Wiener index indicated that the plant diversity was higher in the Brutia Pine plantation, whereas the lowest Shannon-Wiener index was calculated in the Velvet maple plantation. On the other hand Shannon-wiener and Simpson indeces indicated that the soil invertebrates was higher in the Velvet maple plantation, whereas the least index of Shannon-Wiener and Simpson were calculated in the Chestnut leaved oak plantation. In general, one can conclude that the quantitative and qualitative characteristics as well as plant diversity and natural regeneration in the Brutia Pine plantation are higher than that of other two plantations. We should emphasize that this result might be affected by less density in the Brutia pine plantation, where the trees had more growth space and the forest ground receives more light which advances to higher plant diversity. This research emphasizes the use of conifers compatible species in degraded areas as well as thinning operations in plantations. Otherwise, increasing the growth of trees per unit area can lead to reduce the quantitative and qualitative characteristics of trees as well as plant diversity and natural regeneration.