جستجوی مقالات مرتبط با کلیدواژه « غنا » در نشریات گروه « جنگلداری »

Deadwood, at various stages of decay, serves as a diverse habitat for a wide range of species. This study investigates the diversity of macrofauna orders on fallen hornbeam deadwood with different decay classes (four classes) in district one of the Shast Kalate forest in Gorgan, Iran.

Samples were collected from 108 deadwood logs across three altitudinal ranges (200-450, 450-700, and 700-950 m a.s.l.) with three replicates for each decay class and diameter class (less than 40, 40-80, and more than 80 cm). Macrofauna were manually extracted from the deadwood and weighed to the nearest 0.001 g after identification using systematic keys. The diversity of macrofauna orders was assessed using diversity (Shannon-Wiener), evenness (Simpson), and richness (Margalef) indices.

The results revealed significant differences in mean richness, biomass diversity, and abundance of macrofauna among the different decay classes of fallen hornbeam deadwood, with higher decay intensity associated with increased macrofauna richness and diversity. The highest number of macrofauna was found in decay class four and in the 70-100 and 40-70 cm diameter classes. Macrofauna order frequency was highest in the 200-450 m altitudinal range and lowest in the 700-950 m range, with no significant difference between the first two altitudinal classes. A significant negative relationship was observed between deadwood length and macrofauna order frequency.

As altitude increased, biomass evenness increased while biomass richness decreased, suggesting that these factors counteracted each other, resulting in no significant difference in macrofauna order biomass diversity across the different altitudinal ranges.

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.

With sufficient knowledge regarding the presence of fungi and the significance of biodiversity, the forest's management objectives can achieve their sustainability goals. Therefore, in order to properly manage the forest, it is necessary to establish indicators that provide adequate information on biodiversity and monitor changes resulting from management activities. This study aims to identify various macroscopic fungi and investigate their biodiversity in their habitat, i.e., deadwood.

Fifteen specimens of deadwood fungi were randomly selected in Darabkola forest. All macroscopic fungi were numbered and collected, then transferred to the mycology laboratory for identification. The biodiversity of the fungi was calculated using Shannon-Wiener diversity index, Simpson diversity index, richness index, and uniformity index with PAST software

The obtained results revealed that there were 37 species of macroscopic fungi belonging to 27 genera and 16 families. Trametes versicolor, Daldinia concentrica, Trichaptum biforme, and Fomes fomentarius were the most abundant, while Hericium coralloides, Ganoderma resinaceum, Ganoderma adspersum, and Trametes trogii were the least abundant species. Additionally, the families Polyporaceae, Xylariaceae, Ganodermataceae, Pleurotaceae, and Schizophyllaceae were the most abundant, whereas Pezizaceae and Hericiaceae were the least abundant. Most fungi were present in the final stages of decomposition. The results indicated that the mean diversity index for Shannon-Wiener species diversity was 3.24, Simpson species diversity index was 0.95, Margalef's richness index was 6.11, Menhinick's index was 1.95, and uniformity was 0.69. The analysis of the Shannon-Wiener diversity index showed that Trichaptum biforme and Trametes versicolor had a higher diversity value with a score of 1.46.

The results of this study indicate that for the management of fallen deadwood habitats with the aim of increasing the biodiversity of fungi, it is recommended to preserve these fallen deadwood areas within the forest. This preservation would contribute to the revitalization and completion of the ecosystem cycle.

In order to protect and protect forests, these valuable resources, it is necessary and necessary to better understand the relationships between plants and the habitat conditions of these ecosystems and the biodiversity in them. Therefore, this research was conducted with the aim of investigating the effect of slope and altitude from sea level on biodiversity in Arasbaran forests.

30 sample plots of 1000 square meters (0.1 hectare) by dimensions 10 m×100m were surveyed in the study area. In the sample plots, the slope and height above sea level were recorded, and the slope was divided into three levels: <20%, 20-30% and >30%, and the altitude from sea level was also divided into two levels, <1700 m and >1700 m. In the sample plots, diameter at the breast height, type and abundance of species were recorded. The biodiversity indices computed were Simpson and Shannon-Wiener's, Margalf's and Menchnik's richness indices, and Pylo's and Hill's evenness indices. Biodiversity indices values ​​were computedby Past software.

According to the results, the highest frequency was related to the species of Quercus macranthera and Crataegus meyeri. The results showed that Hill's uniformity index decreases initially with increasing slope and then increases. Although the amount of other biodiversity indicators increases with the increase of the slope, statistically, the slope does not have a significant effect on these statistical indicators. Also, altitude above sea level did not have a significant effect on Species diversity indices.

The present research showed that the slope has a significant effect on Hill's evenness index and has no significant effect on other Species diversity indices of plant species. Also, the height above the sea level had no significant effect on the Species diversity of tree species of plant species. This importance can be due to the proximity to residential areas and destruction by villagers.

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.

This research was carried out with the aim of studying the status of natural regeneration and biodiversity (plants and soil invertebrates) of beech forest in three development stages including initial, optimal and decay. After identifying the development stages, one 1 ha sample plot was established in each development stage. Within each sample plot, 10 100 m2 micro-sample plots were laid out as random-systematically. The values of natural regeneration, plant and soil invertebrates diversity in optimal, initial and decay stages have been recorded and eastimated in 30 micro-sample plots. The results of this research showed that natural regeneration in the optimal stage was significantly greater than other stages (7.5 seedlings per 100 m2), while the differences of natural regenerations between the stages of initial (2.9 seedlings per 100 m2) and decay (2.8 seedlings per 100 m2) were not statistically significant. The plant diversity (Shannon-Wiener index) in the optimal stage had the highest values (2.375), whereas the decay stage had the lowest value (1.929). But the differences in the initial stage with other stages were not statistically significant. Also the differences of soil invertebrates diversity (Shannon-Wiener and Simpson indices) were not statistically significant in the studied stages. The decreasing of soil invertebrates diversity (Shannon-Wiener index) in these treatments was respectively as optimal, initial and decay. This research emphasizes the values of natural regeneration, plant and soil invertebrates diversity in optimal stage is better than initial and decay stages.

Reforestation with native and exotic species has a significant effect on the diversity of plant species. This study was done to investigate the effect of Ailanthus stand (Ailanthus altissima) on herbaceous layer diversity in Talesh, Guilan province. Two sites viz. Ailanthus stand and natural forest were selected and 20 400 m2 sample plots were established in each stand as a systematic-random grid. Whittaker's nested plot sampling and minimal area method were used to determine the optimum plot size of the understory. Therefore, micro-plots of the size 16 m2 were established in the center of each plot and cover percentage of each species was estimated according to Braun-Blanquet approach. In general, 21 species of 15 families were recorded in the study area. Results indicated that the average of litter depth, the number of trees per hectare, the average of canopy cover percentage of trees and the average of herbaceous cover were higher in the natural forest. The species diversity and richness indices were higher in the natural forest than those in Ailanthus stand, while evenness index was higher in Ailanthus stand. Studying the abundance distribution models showed that both areas followed a lognormal distribution. Ailanthus species has reduced the diversity and richness indices. Therefore, in order to enhance the plant diversity in these areas, a combination of trees in plantation programs must be used instead of pure plant species.

Road construction is one of the effective factors for ecological changes which affects diversity and species composition in forest roads edges. This research was performed in Kheirud forest to evaluate herbaceous diversity and tree regeneration establishment in different distances from road edge. For this purpose, we sampled herbaceous and tree species regeneration in 0,5,10,25, 50 and 100 m distances from road in down and up-hill sides. Biodiversity indices (Shannon and Simpson), richness index (species number )s)) and evenness index (Pielou) were calculated to determine the degree and magnitude of road effects on herbaceous and regeneration diversity. The results showed that, the species diversity, richness and evenness indices were not significantly related to down and up slope while these attributes were significant to distance from the road. Distance from road edge was a significant factor which affect composition and distribution of herbaceous plants and tree regenerations. In road edges, the first plots (0, 5, 10 m distance) had significantly greater number of light demanding species like Rubus hirtus, Carex remota ,Sumbucus ebulus , Acer velutinum and Alnus glutinosa than interior plots. Based on results, among the environmental factors, light condition was major determinant of species distribution and abundance of road to forest interior gradient. These results are expected to provide critical information for decision makers to design carefully and appropriate forest roads to minimum damages of habitats to establishment of regeneration and also help to select the proper species bioengineering

Aim of this research was evaluated and compared of density (number tree per hectare), basal area and volume characteristics for estimation of tree species diversity in degraded forests. In order to, 73 hectares of Kouhmian forests was inventory based on random systematic pattern with circular plots (10R and 26 plots). In each plot species, DBH and number of tree were measured and recorded. To estimate of tree species diversity was used from Simpson, Hill’s N2, Shannon-Wiener and Mc Arthur’s N1 indices and for calculation of evenness and species richness were used from Wilson- Smith’s and Margalef indices respectively. Also species importance value (SIV) was calculated. The results showed that forest structure is irregular and uneven structure. Also the results showed that in calculation of diversity and evenness indices, if density is selected as calculation criteria, amount of these indices is more than to volume and basal area that are selected as calculation criteria. The results of SIV showed that the highest value of SIV belonged to Carpinus betulus (212.52%) and the lowest value belonged to Zelkova carpinifolia (6.82%). Also Margalef index showed that amount of richness is equal to 1.13.

The objective of this study was to evaluate the diversity of soil invertebrates at Brutain pine (Pinus brutia Ten.) and Cypress (Cupressus sempervirens var. horizontalis) afforestations in Kordkoy region (Mazandaran-Iran). Tending operations have not been performed in these afforestations. For this purpose, invertebrates were sampled in mid-summer, using 20 core soil samples (81 cm2 cross section) to a depth of 10 cm. The fourteen groups of soil invertebrates in each sample were extracted by Berlese funnel and counted by Binocular. Also 20 soil pits of 100×100 cm2 with 10 cm and 20 cm depth were taken and adult earthworms were collected by hand counting. The results of this research showed that the diversity of soil invertebrates (Shanon and Simpson index) with species richness (Margalef index) and species equitability (Heip index) in the Brutain Pine afforestation was greater than Cypress afforestation. Of course it must be mentioned that these differences were not statistically significant. Overall, this study showed Brutain pine has provided a more favorable environment for the presence of soil invertebrates than cypress plantation.

Information about gaps and their sizes distribution is useful for protecting herbaceous diversity. This study was conducted to investigate the effect of gap size on herbaceous species diversity in oriental beech (Fagus orientalis Lipsky.) stand in Asalem, Guilan province. For this study, fifteen gaps in small, medium, and large sizes were randomly selected. Then, herbaceous species were identified in 4 m2 micro plots within the gaps and percent covers of herbaceous species were estimated in the basis of Domin’s criterion. Diversity indices including Shannon-Wiener, Mc Arthur, Hill, species richness and Smith -Wilson, the modified Nee’s, the modified of Hill’s evenness indices were computed. The results revealed that with increasing gap size, the diversity and richness of herbaceous species have been significantly increased, while evenness indices showed no significant differences in different gaps. The highest evenness values were obtained in the small gaps. In small, medium and large gaps 22, 24 and 25 species were found, respectively.

Although quite a few studies have been done in respect to forest structure and development in Iran, there is no study dealing with the evolution of lichens at different stages of forest development. For this reason the research has been carried out to study lichens diversity and identify reference and indicator species for each forest development stage at Gorazbon series of Kheyroud forest at Caspian region of Iran. After separating the different forest development stages at the series, sampling was made from all trees with more than 40 cm dbh at each stage, using a 40 x 60 cm frames to record lichens type and frequency. Richness, evenness, diversity and dominance indices at different development stages were calculated and compared, applying Variance Analysis and Duncan test. Results showed that there are significant differences between the development stages in respect to lichens diversity indices and they were the highest at destruction stage, except for Berger-Parker dominance index. Furthermore, results of Detrended Correspondence Analysis (DCA) showed that classification of the development stages in relation to the lichens cover data, leads to formation of specific groups with relatively high separation potential. Overall, 38 lichens species have been identified and according to Analysis of Indicator Species (IV) and Monte Carlo test, there were significant correlations between each of the optimal, ascension, and destruction stages of the forest developmental and 8, 17, and 13 numbers of lichen species, respectively, which are clearly found to be classified and differentiated with such significant differences.

In order to identify the diversity of tree species in relation to physiographic factors (elevation، aspect and slope)، the Kandelat Forest Park with an area of 614. 85 hectare was surveyed، where is located southeast of Rasht city. For this reason، maps of slope، aspect، elevation and dominant vegetation types were provided، using GIS technology. As a result، 18 homogeneous units were obtained by layering the mentioned maps. In each homogeneous unit، five sample plots، and totally 90 plots were randomly located. The trees at each plot were found and their diameter at breast height (dbh) was measured. Overall، 17 tree species belonging to 16 genera and 12 families were identified. Result revealed that aspect had significant effect on diversity and evenness of the tree species. Species diversity and evenness on south aspect were significantly more than the other aspects. In addition، elevation had significant effect on diversity and species diversity and richness were greater at high elevations. There was not significant effect of slope aspect on tree''s species diversity، richness and evenness.

The most important role of the litter invertebrates is leaf litter decomposition and helping of nutrient elements cycling. The objective of this study was to evaluate litter invertebrates dversity within 20 years old plantations of alder (Alnus subcordata C. A. Mey.), maple (Acer velutinum Bioss.), oak (Quercus castaneifolia C. A. Mey.), cypress (Cupressus sempervirens var. horizontalis) and natural forest in Darabkola (Mazandaran-Iran). For this purpose, one sample plot, each 1 ha was selected in every plantation as well as in the natural stand. In each sample plot 10 micro plots, each 100 m2 were selected random-systematically. Litter invertebrates were sampled by removing, by hand, all leaf litter in 100×100 cm quadrats. Fifty samples were taken each time and during four seasons 200 samples were taken. Invertebrates were separated out visually in the lab and transferred to 95% alchol, after sorting and counting. More over, various parameters of the stands and soils were measured in each micro plot. For determination of soil invertebrates diversity in these treatments, Shannon and Simpson indices were used, while for determination of species richness and equatibility, Margalef and Heip indices were applied. The results of this research showed that although the differences between the annual means of litter invertebrates diversity was not statistically significant in studied sites (p=0.05), but the decreasing of diversity index in these treatments was respectively as reforestations of alder, maple, natural forest with cypress and oak reforestations. Also the analysis of PCA showed that the parameters of temperature, crown canopy, relative light intensity, moisture content of soil and litter and the amount of P and C/P of litter take an important role in seasonal differences of litter invertebrates diversity in treatments.

This paper aims to study the plant biodiversity in a natural forest and the adjacent 20-years-old plantations of Alder (Alnus subcordata C.A. Mey.), Velvet Maple (Acer velutinum Boiss.), Chestnut-leaved Oak (Quercus castaneifiolia (C.A. Mey.) and Cypress (Cupressus sempervirens var. horizontalis) in Darabkola, Mazandaran province, north of Iran. For this purpose, one sample plot, each 1 ha; was selected in every plantation as well as in the natural stand. In each sample plot 10 microsample plots, each 100 m2; were selected random-systematically. All of the plants were determined in the sample plots and their coverage percent were estimated in four seasons. Moreover, various parameters of the stands and soil properties were measured in each sample plot. For determination of plant species diversity in these plots, Shanonn’s and Simpson’s indices were used, while for determination of species richness and equitability, Margalef’s and Heip’s indices were applied. The results showed that Alder plantation and natural forest had the highest values, whereas Cypress plantation had the lowest value for species diversity. The highest Species diversity in other plantations was for Velvet Maple, Chestnut-leaved Oak and Cypress, respectively. The analysis of PCA showed that seasonal differences of species diversity on our studied plots were affected by the crown canopy of plants in the upper-story, and the under-story crown canopy of plants with the number and density of plant species in the under-story as well as by environmental parameters including rainfall, temperature and relative light intensity.

In temperate forests, disturbances are regarded as processes of great importance to forest vegetation. For the better perception of biodiversity, different indices were used in mountain forests of Lalis located in Chalous. Line transect method used for sampling, and plant abundances were recorded, as well. Forest gaps areas were divided into four classes including smaller than 200 m2, 200 - 400 m2, 400 - 600 m2 and larger than 600 m2 areas. In order to analyze of biodiversity, Simpson, Shannon and Wiener, Margalef, Menhenick, Peet and Camargo indices were used. Using analysis of variance, statistical difference between biodiversity indices in respect to gap sizes was found. The maximum and minimum of divers species and richness species indices were related to very large and small gaps, respectively. The highest evenness indices were related to medium and large gaps, whereas the least of evenness indices were related to small and very large gaps.