فصلنامه تحقیقات جنگل و صنوبر ایران
سال بیست و نهم شماره 2 (پیاپی 84، تابستان 1400)

Biodiversity conservation is one of the most important challenges in forest ecosystems, especially where the local people's livelihood is highly dependant on that resources. Obtaining information on the potential and present condition of vegetation diversity is an important step to conduct successful conservation plans. In this study, we sampled 32 plots in sacred groves with no grazing or disturbance evidence and 90 plots in surrounding silvopastoral woodlands with a continuous grazing and pollarding history. We compared species diversity, life form, and chorotype of vegetation composition between these two stands and we determined the most important environmental gradients affecting this composition. The result indicates that sacred groves have significantly different species diversity, life forms, and chorology compositions than their surrounding woodlands. Out of 254 species identified in this study, 95 species are shared between both sites; 114 species are uniquely found in sacred groves that most of which have phanerophyte, hemicryptophyte, or cryptophyte life forms, and Irano-Turanian, Meditteranean, or Euro-Siberian Chorotypes. Surrounding silvopastoral woodlands contain 45 unique species as well as therophyte and chameophyte as the major life forms and Irano-Turanian, Meditteranean, or Saharo-Sindian chorotypes. Sacred groves as a network of less-disturbed stands, with higher canopy and litter cover without grazing and pollarding provide a better ecological condition for a variety of valuable plant species and considering their traditional protection by local people they play an important role in conserving biodiversity in northern Zagros.

In this study, the effect of soil and water affected by municipal effluent on the performance of three poplar clones of Populus nigra L. after one year was investigated in a factorial experiment with two factors (1- soil and water in two levels and 2- poplar clones in three levels) based on the completely randomized design with five replications. After one year, in three poplar clones, significant increase in growth and biomass parameters of plants treated by soil and water affected by municipal effluent was observed. In three poplar clones, the significant increase of nutrients and heavy metals in organs of plants treated by soil and water affected by municipal effluent was observed. In three clones, Fe, Cu, Ni, Cr and Pb were mainly accumulated in roots, whereas Zn and Mn showed the highest concentrations in leaves. The three poplar clones did not show statistically significant differences in terms of uptake and accumulation of nutrients and heavy metals in plant organs. The effect of clone on most growth and biomass parameters was significant (p ≤ 0.01). The highest growth and biomass rates were seen in plants of P. nigra 62/154 treated by soil and water affected by municipal effluent. The results of the present study showed that for wood farming in lands affected by municipal effluent, all three poplar clones can be used by prioritizing the P. nigra 62/154 clone.

Oak (Quercus spp.) forest cover is one of the most important living ecosystems in the western region of Iran and the Kermanshah Province. One of the important managerial needs of this cover is the water requirement of the oak plant. Currently, determining the amount of water required by the oak plant is one of the main priorities of the country's natural resources sector. Among the practical methods for estimating the evapotranspiration of vegetation (water requirement) at different levels are remote sensing techniques. In this study, in order to determine the rate of evapotranspiration of forest cover in the Robat Mahidasht region in the Kermanshah Province, the SEBAL algorithm and four images of Landsat 5 in the period of June, July, and august of 2010 were used. Then, using Sentinel satellite images, the forest areas of the Robat-Mahidasht region were extracted and matched with the calculated evapotranspiration map. Based on the obtained results, the average rate of 24-hour evapotranspiration of forest cover in the desired time period has varied between 3.4 to 5.09 mm. The correlation coefficient between the estimation of evapotranspiration by SEBAL and lysimetric measurement in Mahidasht region was about 0.9967 and the absolute difference between them was about 0.53 mm per day, which indicates an error of less than 10%. The estimation of SEBAL algorithm is acceptable. Remote sensing technique and the SEBAL algorithm can be used in the compression classification and even the health of forests if there is a suitable sequence of images and with the help of satellite data of other sensors such as Sentinelimages.

Nowadays, the oak decline phenom in the Zagros region of Iran has converted into a serious crisis that needs more attention and research to provide forest managers with solutions. The aim of the study was to understand the soil quality and leaf nutrients of declined oak stands (Quercus btantii) in the Kohmareh Sorkhi region. To do so, soil samples were taken from the under of the healthy and declined trees’ crowns and then soil characteristics including moisture content, pH, electrical conductivity (EC), organic carbon, nitrogen, phosphorus, potassium, gypsum, calcium carbonate, calcium, and magnesium contents were measured and compared. Morover, NPK content was measured on taken leaves from each trees. The results indicated that soil moisture, EC, gypsum, lime, P, K, Ca, and Mg contents had significant differences. Although gypsum and lime contents were higher in the declined stands compared to the healthy ones, moisture content, EC, P, K, total Ca, and Mg content were higher in the healthy stands. The leaf nutrient statistical analysis demonstrated that the dieback individuals suffer phosphorus shortage, but N and K content were the same as the healthy ones. Given that some shortages were observed in the nutrient elements such as P, K, Ca, and Mg in soils under the crown of declined trees and P in their leaves, it seems that the nutrient shortage has an important role in the oak decline since the greatest shifts were recorded for which.

Dead trees are one of the most important structural features in natural stands that knowledge of the processes associated with them is essential in understanding the evolution and development of forest stands. The main purpose of this study was to estimate the quantitative and qualitative characteristics in the natural beech forests during the stage of growing-up volume in the Kheyrood forest of Iran. For this purpose, three one-hectare sample plots with structural features of growing-up volume stage were selected. In each plot, species, diameter, length, shape, and degree of decay of all dead trees were measured. The proportion of snags was 32.8%, while 67.2% of dead trees were recorded as log. The highest and lowest number of deadwoods belonged to beech with 86% and alder with 6%, respectively. The results showed that 73.8% of the total number of measured deadwoods related to primary decay degrees and 26.2% were in the advanced degrees of decay. The highest frequency of deadwoods in diameter classes in the study stands was measured in low, very thick, medium and thick diameter classes, respectively. The highest and lowest mortality rates in the diameter classes were calculated in the low- and thick-diameter classes, respectively. The average volumes of deadwoods in different diameter classes were significantly different. In general, in order to identify changes in the stand structure over time and to investigate the dynamics of deadwood in the growing-up volume stage, it is suggested that the stand analyzed here be monitored in the future.

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.

Climate change can be a major threat to the endemic species of the Hyrcanian forests. However, there have been almost no studies in terms of determining consequences of climate change on the distribution patterns of Populus caspica Bornm. In this study, ecological niche theory and MAXENT software as well as P. caspica presence data across the Hyrcanian forests of Iran were used to identify the relationships between species data to the climatic predictor variables under current and future (RCP 8.5) (2070) climate conditions. According to analysis of area under the ROC curve, the high value of AUC index (0.993) indicated the efficiency of the model in determining the potential habitat of P. caspica. Precipitation of driest month, temperature annual range, mean annual temperature, and isothermality were the most important bioclimatic variables in the determination of potential habitat for P. caspica. Moreover, our results demonstrated that the habitat suitability area of this species was 88317.3 km2 under current climate condition and 38.75% area was identified as a "good potential" level for the presence of P. caspica. Whereas under projected future climate (RCP 8.5), suitable areas would be decreased by 48.4% compared to the current condition. The results of this study can be applied in approaches management, conservation planning and reforestation by taking into account the effect of climate change on habitat suitability and species response to its changes and conservation strategies will be compiled for this species.

In light of the increase in demand for recreational forest areas, it is imperative to determine factors influencing visitor attitudes to better anticipate recreational needs and improve the management of these areas. Due to its natural and historical attractions, the Dalab forest area is considered one of the most important areas of tourism potential in the Ilam Province, Iran. By using the contingent valuation method, this study estimated the recreational value of this area. A logit model was evaluated by the likelihood ratio test to investigate the factors affecting the willingness to pay (WTP) for visiting it. The information was collected by filling out questionnaires by 180 visitors to the area with independent income in 2020. The results showed that family size, education level, marriage, owning a car, annual income, and the level of security in the area all contribute positively to visitors' WTP, but being a passenger, the length of the visit, and the amount offered of entry provided negatively affect the quality of this characteristic. 81.66% of respondents were willing to pay an entrance fee to visit the Dalab forest area. It was estimated that the respondents would be willing to spend on average 47690 Rials on a visit to this recreation area. Furthermore, the annual recreational value of the Dalab forest area was estimated at 476.9 million Rials, which is the equivalent of 184.7 thousand Rials per hectare. The results demonstrate that the region has a high recreational value, indicating its importance for sustainable management as one of the Zagros' most valuable ecosystems.