نشریه بوم شناسی جنگل های ایران
پیاپی 13 (بهار و تابستان 1398)

The present study aimed to investigate the accuracy and precision estimation of the number, basal area and volume of the standing trees by methods of random and systematic random sampling in the forests of West Guilan. The cost or inventory time was determined using the criteria (E%2 × T). Inventory was carried out by complete sampling (census) in an area of 52 hectares. The study area (section 11, district 2, Nav forests, Asalem) was divided into 520 rectangular plots (50m×20m) and each plot was measured separately. Measured characteristics were the kind of tree species, diameter at breast height and height. After inventory operation, the study area was stratified based on forest density. In each stratum, sampling was carried out by simple random sampling and systematic random sampling. The results showed that implementation of stratified sampling has reduced the sampling error and increased the sampling time for estimating the characteristics of abundance, basal area and standing volume of trees per ha in the study area. Amount of criterion (E%2 × T) in stratified sampling was less than sampling without stratification and between stratified samplings; stratified random systematic sampling had the lowest value. Therefore, among the studied methods, stratified random systematic sampling, due to high precision and minimum criteria of (E%2 × T), was a suitable method for evaluation of the number, Basal area and volume of standing trees in the study area.

Taxus baccata L. is a native and ancient tree species growing the Hyrcanian forests that have been considered in recent years because of being in the red lists of threated species. The aim of this research was to provide quantitative characteristics of forest stand structure using a set of indicators in the natural habitat of this species. Three one-hectare sampling area were selected to reveal the quantitative characteristics of the yew stands structure. In the study area the 30×30 m gird plot was established. In the intersection point of girds (n=36) the closest beech to the intersection point as reference tree and other three nearest neighbors the to the reference tree was selected and diameter at the breast height, tree height, crown diameter, distance and angle among trees were measured .The set of indices including such mingling, diameter and height differentiation, tree to tree interval distance and Clarke and Evans index were employed to quantification of stand structure. Results showed that the uniform angle index value was 0.64 and Clarke and Evans were around one this means the yew randomly distribute in this forest. The mingling index estimated 0.61 that means English yew tends to mixed with other tree species. According to the diameter and height differentiation, yew stands have slightly heterogeneous diameter distributions, uniform tree height and the stems have an average distance between trees of 2.0-4.0 m. The English yew is a threatened tree species and in its natural habitat tends to be mixed with other species (often with hornbeam), have slightly heterogeneous diameter and height distributions. The reduction of young Yew trees as a result of the mortality of trees in a diameter classes less than 15 cm and the high competition of Yew with other tree species requires more consideration and effort to conservation of this species in the sites.

The use of lightweight and cheap UAVs to detect the health of forests and identify the tension of planted can be useful to prevent the spread of pests and diseases. In the present research, a lightweight quadcopter drone with a 12-megapixel camera, visible light range was used. This UAV was emploied to detect leaf tension of pure Quercus Castanifolia plantation, pure Acer Velutinum and their mixture in nine sample with 1-3 hectares. Flight at altitudes of 40, 70 and 100 meters was used to determine UAV ability for detecting areas plantations tension. The flight plan was designed in the form of 75% latitude coverage and 80% longitudinal coverage. Supervised classification such as Neural Net, Support Vector Machine (SVM), Maximum Likelihood and Mahalanobis Distance algorithms are used and 25% of samples were used to check the classification accuracy. Visible color saturation image and some vegetation indices such as vegetation index (NGRDI) and (EXG), has great potential for detecting leaf tension in trees and seedlings. The Jeffries-Matusita coefficient ranged from 1.81 to 1.97, and the Transformed Divergence was 1/87 to 1.98, indicating the degree of separation of educational samples. The overall accuracy of Support Vector Machine (SVM) algorithm as best method was 83 to 96.7 percent for all samples and the kappa coefficient was 0.89 to 0.98. The results revealed the high capability of visibility light sensor cameras mounted on a UAV in detecting tree leaf tension. The best flight height is between 70-100 M. Using image enhancement techniques, especially color saturation and vegetation indices, the range of visible light spectrum such as vegetation index (NGRDI) and (EXG) to detect leaf tension increase the effectiveness of these images. Design of an automatic imaging system adapted to the altitude variation of the tree crown is recommender in order to prevent a minimum level of overlapping.

Forest structure consider the spatial arrangement of trees characteristics such as age, size, species, gender and so on is.This study aimed to investigate the structural diversity of three one-hectare stands in the gap making phase, were studied. For this purpose, three sample plots with a one hectare area were selected in Asalem beech stands which belonged to the structural features of the gap making phase and studied. In each plot 30×30 m network were established. After implementing the network, the quantitative and qualitative features of the two beech trees at the closest distance to the intersection of the network as the references trees number one and two with three neighboring trees belonging to each of the references trees located at the nearest distance, was taken. The distance between the references trees and neighbors, as well as the distance between the neighboring trees, were measured relative to each other, and based on the Pythagorean trigonometric relationships, the angle between the references trees and the neighbors were measured. According to the results of this study, the average of species mingling, diameter differenation, height differenation and neighbor distance is 0.23, 0.43, 0.87 and 4.87 meters, respectively. By using of data from structure of intact stands, not only the current structure of various species can be quantified but also, their evolutionary process as well as the results of the forest management activities can be assessed.

This study was carried out in managed and unmanaged Fagus orientalis L. (beech) stands in the Asalem beech forest in order to compare the composition and diversity of plant species. Three V-shaped catena landforms were selected for each stand. Then, large quadrats, 400 m2 area, with selective method and within each of them, small quadrats, 4 m2 area, were established along each catena and slope position (summit, shoulder, backslope, footslope, topeslope) to study the density and species diversity of trees, composition and species diversity of regeneration and herbaceous species, respectively. Simpson, Margalef and Camargo indices were employed for diversity, richness and evenness analysis. The result showed that beech had the highest crown cover and regeneration density. Slope position analysis showed that significant differences in Simpson diversity and Camargo's evenness indices in trees and Simpson diversity and Margalef richness in herbs. There was no significant difference between indices regarding to regeneration. Dryopteris filix-mass L. and Asperula odorata L. exposed the highest frequency in managed and unmanaged stands, respectively. Considering the dominant form of land in north forest habitats of Iran is catena landform; it is necessary to implement silviculture's plans (protection, restoration, development and utilization) with particular attention to catena management.

Natural regeneration is one of the key aspects of forest sustainability and a tool to decide on restoration programs in forest areas. The purpose of this study was to investigate the quantity of natural regeneration of Acer campestre L. as one of the most important tree species in Arasbaran forests and its relationship with elevation changes and structural characteristics in the natural stands. For this purpose, two habitats in two altitudes (less than 1500 meters and more than 1500 meters above sea level) were identified in the Kaleybarchay watershed of Arasbaran forests. In each elevation, three sample plots (one hectare area) were used to measure the structural characteristics (including density, basal area and canopy cover) by the whole trees inventory. The regenerations were classified in three classes: sapling (height greater than 1.30 m), large seedling (0.30-1.30 m height), and small seedling (height less than 0.30 m) per hectare in 10 circular micro-plots (100 m2) in each one hectare. The results showed that the saplings density was significantly higher (p≤0.05) only in the low elevation. The structural characteristics of the stands showed that only the difference between the basal areas of trees in different elevations was significant. Relationship between structural characteristics and regeneration density showed that there was a significant difference between the basal area and the density of saplings and regeneration density of the large seedling class and the canopy cover was significant. The findings of the present research let to better understand the ecological nature of this species in the early stages of life, will help to decide on environmental constraints for the establishment and continuation of the successful regeneration, and could help to more effective management for conservation and cultivation operations.

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.

Ecological condition including physiographic factors have impact bon plant species diversity. There for it is necessary to investigate at the ecological condition in other to achieve sustainable development and natural ecosystem conservation. The present study aim is investigate the effect of physiographic factors (altitude and geographic directions) on the biological diversity of plant species in the middle Zagros forests. The investigate was conducted in Research and Education Forest at Razi university located in between the west cities of Kerend Gharb and Sarpole Zahab, in Kermanshah province. The studied area was divided into three elevation class including less than 1000 m, 1000 to 1500 m and more than 1500 m asl. In each class of elevation and direction, respectively 32 and 48 plots of circular shapes of 1000 square meters in random- systematics were taken. In order to study the shrub layer in each circular sample plot, a plot of 25 m2 and a microplate of one square meter to study the herbaceous diversity were taken. The results showed that the highest values of diversity indices for tree, shrub and herbaceous cover in altitudes from (1500-1000) were observed and ANOVA test showed significant different between diversity index in three elevation classes. The results of compare biodiversity index in two main aspect showed that in trees and shrubs layer maximum of diversity index observed in the northern slopes, but for herbaceous layer, maximum of diversity index showed in southern slopes and T-test showed significant different of biodiversity index in two aspect direct.  Overall results showed that the physiographical parameter (Elevation and aspect) are a significant effect on diversity condition.

Wild pistachio forests in terms of the harvesting of various types of products and in terms of energy production and fuel wood are severely exposed to destruction. One of the effective methods for preserving and developing these forests is helping them with artificial regeneration. The purpose of this study was the most appropriate Irrigation, sowing depth and seed cover for seed of Wild pistachio in Kushkan nursery of Zanjan province. For this purpose experimental design in a completely randomized at three different sowing depth treatments including (0-3/99), (4-6.99) and (7-8 cm) and four seed covers including (50% soil + 50% manure) (50% soil + 50% sand), (50% soil + 50% zeolite) and (50% manure + 50% (soil, sand and zeolite)) and two irrigation including with irrigation and without it with six replications designed and collar diameter, plant height, root height, stem length to root, root and shoot dry weight ratio and percent survival was measured. Then, for comparing the mean and the effect of treatments on each mean, the analysis of variance, Duncan test and t-test were used. ANOVA test showed that different treatments of irrigation, sowing depth and seed cover had significant effect on characteristics measured of planting. The best result for seeding Baneh considering the interactions of the studied treatments was at surface depth (0-3/99 cm) with (half manure + half (soil, sand and zeolite)) and with irrigation.

One of the important features of plant communities is the spatial pattern of trees. The spatial pattern of the stands determined by measuring and positioning of trees in the stands and inserting them in analytical frameworks. This is because spatial information allows natural resource managers to make and perform better-informed decisions, -. The aim of this study was to assess the spatial pattern of Acer velutinum in two stands, above and below 800 m from see level in Asalem Nav forests, Guilan province. The sampling distance- method was used. In order to gather the required data, characteristics of 88 tress in 30 sample plots (1000 m2) were recorded in two elevation classes in an area of 30  ha (15  ha in each elevation class) with a grid  network of 100 × 100. The number of trees, diameter, height, distance from the nearest tree to the sample plot and distance of the nearest tree to the first tree of maple was measured in each sample plot. To analyze the spatial pattern, the Hopkins index, the variance/average ratio, Morisita dispersion,  Morisita, Johnson, and Zimmer standards were used, which randomized, uniform, maximum uniform (for both Morisita and Morisita standard indexes) and uniform patterns dispersion was observed, respectively. In general, the ability of these indices makes it possible to compare the stands and they can be used as a suitable tool for sustainable management of the northern forests of Iran.

Quantifying forest growth and determination of its affective factors are fundamental for forest management. This study examines the effects of biotic and abiotic factors on the diameter increment of oriental beech (Fagus orientalis Lipsky) in a high-elevation forest in northern Iran using permanent sample plots. The aim of this study was identification and quantifying environmental factors such as potential solar radiation in growing season, topographic wetness index in representing soil water distribution seasonal air temperature, topographic wetness index (as indicator of soil water distribution), wind velocity generated from simulation of fluid-flow dynamic models of complex terrains, temperature and humidity and their relation with diameter increment of beech. On the basis of diameter measurements in a 9 year period (2003-2012) a model was used in order to estimate diameter increment. Also, mean of DBH and basal area of beech trees were implemented in model as biotic factors. The results showed that DBH, combination of topographic and soil water index factors and basal area are the most important factors affecting diameter increment of beech trees, respectively. Eventually, the results showed that by using increment models, it is possible to determine the increment of diameter and factors affecting it with high accuracy.

This research was carried out with the aim of dormancy breakage and seed germination improvement in mature and immature seeds of T. rubra subsp. caucasica form angulata. The seeds were collected from middle altitude (500 a.s.l.) forests of Chamestan, north of Iran. Mature and immature seeds with pericarp were treated as 1) cold stratification (without pretreatment), 2) imbibed with NaOH (30%)+cold stratification. Also, mature and immature seeds without pericarp were treated as 1) imbibed with gibberelic acid (500 mg/l)+cold stratification, 2) imbibed with kinetin acid (1 mg/l)+cold stratification. The examination was performed as completely randomized design with three replications. The highest amount of seed germination belonged to mature seeds without pericarp-imbibed with pretreatments of acid (giberelic or kinetin) and also immature seeds with pericarp-without pretreatment. The highest germination speed allocated to immature seeds with pericarp-without pretreatment, and the maximum mean germination time to mature seeds without pericarp-imbibed with giberelic acid. The results of this research showed that for optimizing seed germination of this species with above mentioned provenance, the best conditions for seed germination is, immature seeds with pericarp, subjected to cold stratification (without any pretreatment).