hyrcanian forests

After the logging ban for Hyrcanian forests, it is necessary to investigate its consequences. The purpose of this research is to identify the appropriate strategies resulting from the logging ban for future forestry plans. First, the positive and negative consequences were adjusted according to the origin of the effect in the form of internal and external SWOT factors. After screening items with acceptable validity and reliability, from the conflict of internal and external factors, four SWOT strategies including progressive (SO), competitive diversity (ST), revision (WO), and defensive (WT) strategies were determined. 45 strategies based on sustainable management were evaluated by the TOPSIS technique using a Delphi survey (15 experts) with purposeful sampling and a 7-point Likert scale. The results of Shannon's entropy calculations showed that the Strategy of management structure, local forest communities, ecological and health values, dealing with risks, and other global forest functions have the most weight and influence in the ranking of sustainable management strategies. The results showed that according to the Pareto principle, 34 strategies have 80% importance. Therefore, for sustainable management, a wide range of decisions should be taken in forestry plans. logging ban strategies include the expansion of wood farming, conserving habitats, special trees, ruined parcels, and the outskirts of villages, wood and non-wood exploitation subject to the elimination of forest destruction factors with the participation and increase of the income of traditional users and the design and implementation of forestry plans as Balanced in all forest areas with more restrictions on traditional animal husbandry and interaction conditional on protection and restoration with forest herders and the triple integration of management, environmental and social perspectives in the supervision of forestry plans, promotion of education programs and promotion of natural resources. Basic exploitation by growing young stands, reducing natural hazards, increasing wood cultivation, eliminating hydrological disturbances in the forest road zone, and implementing forestry plans based on sustainability criteria are considered to be the most important solutions for sustainable forest management.

Gaps affect the soil and other ecological features by affecting the amount of light inside the forest. In this study, the effect of natural and artificial gap of mixed and pure stands of Fagus oreintalis on the physical and chemical properties of soil was investigated. For this purpose, 24 trees in the mixed type and 24 trees in the pure beech type were selected in the Hajikola-Tirankoli forestry project from the Tajan river watershed, in 2015. These gaps are classified into three classes: small (less than 150 square meters), medium (between 150 and 350 square meters) and large (350 to 500 square meters). In each gap, 5 plots were made on the diameters. Inside each plot, a soil sample was prepared from a depth of 0-30 cm and a composite sample was prepared. In addition, a control soil sample was also prepared outside each gap. The gap size had a significant effect on pH, EC, potassium, carbon, nitrogen while, the type of stands had significant effects on organic matter and nitrogen (P<0.05). Also, the interaction effects of gap size and stand type had significant effects on nitrogen, organic matter (P<0.05). The highest amount of potassium was observed in large gaps (with an area of ​​350-500) in pure beech stands and the lowest in mixed stands. The results of the present study showed that the amount of carbon, organic matter, nitrogen and potassium increases with the increase of the gap size. In the gaps resulting from cutting (artificial), the highest amount of nitrogen was observed in the large gaps of pure beech mass. There was more organic matter in the large gaps than the small ones. Also, the gap size and the stand type had no effect on the amount of phosphorus in the soil. Therefore, it can be said that in the mixed stands, especially in large gaps, soil fertility is higher than in small gag in pure stand.</span></span></span></div>

The wood quality in forest trees largely depends on their self-pruning and forest management pays attention to the pruning factor to achieve high quality of wood products. Therefore, this study aimed to determine the relationship between self-pruning index in Oriental beech trees and some of their structural attributes. For this purpose, 186 beech trees were randomly selected in Alandan, Sari and the self-pruning index along with other structural features were measured. The correlation results showed that there is a significant positive correlation between self-pruning index with DBH, crown length, area and crown volume and also a significant negative correlation with symmetry and crown ratios. No significant difference was observed in the height classes of beech trees in terms of self-pruning index (Sig.=0.164). The highest mean value of the pruning index belongs to the class of 75-46 cm in diameter (Sig.=0.002). The analysis of variance results showed that the highest mean value of the index was present in the groups of three trees. With increasing the stubbiness ratio, the self-pruning index increased (p=0.009). A significant interaction was observed between stubbiness ratio with crown length, crown area and volume, DBH and height of beech trees in site. In general, the results showed that self-pruning in large-sized beech trees was performed according to forest conditions and this important index was related to the structural attributes of trees such as height, DBH, surface area and volume of the crown and it is also necessary to consider the pruning of forest trees in intermediate-cutting operations to increase the wood quality.

Caspian Hyrcanian mixed forests, on the southern shores, of the Caspian Sea, with 110 km wide and 800 km long are composed of temperate deciduous trees Hyrcanian is a biome in the ecosystem of mixed broadleaf forests on the southern edge of the Caspian Sea and the northern edge of Alborz, which has expanded in the southern and southwestern front of the Caspian Sea and parts of northern Iran and the Republic of Azerbaijan. This forest, which is considered a unique genetic reserve in the world, Scince the Paleogene period, it began to expand and so far it has undergone various climatic events. Fajan, Ziyarat, Karaj, Kond, Aghchegil, Apsheron, and Hezar-Dareh formations were deposited simultaneously of seawater intrusion and retreat and Alborz has taken its current form. The shale and marl of the Fajan sub-conglomerate indicate the advance of the sea and the red-colored conglomerate of Fajan is a sign of exit from water and depositionin a dry environment. The last advancementof the carbonate sea was accompanied by the expansion of the Ziyarat Formation in the Middle Eocene. The Karaj formation also indicates the volcanic conditions in the Middle Eocene, despite the tuffites. In the Pliocene to Pleistocene and the early Quaternary, it was strongly affected by the glacial periods of the Northern Hemisphere, and even Quaternary volcanoes such as Damavand have also caused damage to this forest habitat, but these forests, under the influence of the favorable climatic conditions prevailing in the northern Alborz, have started to advance and expand. The current appearance of Alborz was affected by the tectonic movements of Laramide (at the end of the Cretaceous), Pyrenean, and Attican in the Cenozoic in order to providea suitable platform for the emergence and expansion of Hyrcanian forests.

The present study aimed to examine the effects of stratification on tree layers diversity and some features of beech trees in Hyrcanican forest, Guilan, Asalem. Also, interactions between tree diversity and some characteristics of beech leaves was investigated. The Nine research plots are sampled as a gradient from pure beech stands to mixed stands with up to 9 deciduous tree species with three replications for each. Each research site had a size of 2500 m2 (50 m × 50 m). In each tree layers, diversity indices, crown diameter, DBH and frequency of beech tree were measured within plots. The results showed that the highest value of richness and diversity indices belonged to the second tree layer. The highest amount of basal area and crown diameter were observed in the first tree layer (overstorey). Regression analysis showed that tree layer diversity and richness measures were significantly positively correlated with fresh and dry weight of beech leaves. Correlation coefficients indicated that beech frequency was significantly positively correlated with weight of fresh leaves and negatively with dry weight of leaves. There was significantly negatively correlation between basal area of beech trees with fresh and dry weight of leaves within stands. In general, it can be stated that diversity-functioning relationships might occur in the tree-layer of the deciduous beech forest under investigation.

Knowing spatial pattern of plant communities is necessary to recognition of forest ecology and management. In order to investigation on the spatial distribution pattern of wild cherry, forest management plan of Hajikola-Tirancoly in Mazandaran Province was selected. The locations of Prunus avium L.individuals with 100% inventory were recorded through GPS equipment in three areas of case study such as: Fagus type, protective area and plantation area. Qualitative characteristic of trees crown (symmetrical or unsymmetrical) and diameter at breast height was recorded. In order to achive spatial structure, landscape analysis and metrics in class level ( with symmetrical and unsymmetrical crown) was applied using Fragstats and Arc Gis softwares. The results indicated that number of Prunus avium L. were 160 trees in our case study. Highest and lowest distance among trees was observed 67 and 121 meters, respectively. The results of metrics analysis showed that the distribution pattern of wild cherry in Fagus type was clumped pattern and protective area was uniform. The results of metrics Shannon- Wieners evenness (uniformity) and Simpson’s diversity showed that the highest diversity and spatial arrangement was in Fagus type.

Having the richest plants biodiversity, Hyrcanian natural mixed-beech forests contribute to the huge carbon pool in the different soil layers. This research aims to develop modeling soil carbon sequestration in terms of the plant biodiversity indices to manage soil carbon stock with respect to trend of sustainability, fertility, carbon cycle, and planning to face with climate change in local/ regional scales. After measuring plants biodiversity indices and soil carbon factor over the field operations, simple and multiple linear regressions as well as curve estimation regression were applied in the process of modeling. According to Adj.R2, SEE and AIC, simple and multiple linear regressions had no considerable accuracy (AICmin = 힝.74). Analysis of non-linear models showed that model S including index of species dominance belonging to herbal coverage was the best predictor with the least error and highest certainty (AICmin= -171.23) to estimate soil carbon pool in the studied forests. In the following, the results showed that although the log-transformed models with increasing the parameters and adding the correlated explanatory variables were valid (VIF

Rotten and dead trees are the main component of forest ecosystems and play an important role in maintaining forest biodiversity. In this research frequency and characteristics of large diameter trees (normal, rotten, and dead trees) with diameter at breast height greater than 60 cm were studied in two compartments (selective logged and protected) in Asalem-Nav forest. Random systematic sampling method with grid of 100 × 100 m and plot area of 0.2 ha was used for data collection. The results showed frequency and volume of large diameter trees of all three groups in the logged parcel were lower than protected parcel (P

The purpose of the present research was to investigate the interactions between tree layer diversity and some morphological traits and nutrient elements of hornbeam leaves in forests of Asalam, Guilan. Nine research plots (50m×50m) are sampled as a gradient from pure hornbeam stands to mixed stands with up to 9 deciduous tree species. Tree layer diversity and richness indices were measured and also leaves of hornbeam (Carpinus betulus L.) trees were sampled in overstorey within each plot. The results showed that there was no significant correlation between tree-layer richness and diversity values and leaf traits including leaf lenght, petiole lenght, veins distance, leaf thickness, leaf area and serration number. But, Regression analysis showed that tree-layer diversity and richness measures were significantly negatively correlated with leaf width, fresh and dry weight of leaves. Correlation coefficients indicated that basal area of hornbeam trees was significantly positively correlated with weight of dry leaves and and negatively with special area of leaves. The result revealed that there was significant positive correlation between tree diversity and Mn amount and ADF, but tree richness had significantly positively correlated with ADF.