فصلنامه تحقیقات جنگل و صنوبر ایران
سال سی‌ام شماره 1 (پیاپی 87، بهار 1401)

Knowing the habitat conditions of forest species is one of the primary principles for understanding forest ecosystems. This research aims to study the quantitative and qualitative characteristics of wild cherry (Cerasus avium L.) in ‎different aspects and elevations, and determine the most important ecological factors affecting ‎these characteristics. The study area is Kalibar Chay and Ilgenhe Chai of Arasbaran forests in ‎Kalibar county. According to the physiographic conditions of these regions in two elevation classes, ‎‎1000-1500 and 1500-2000 m.a.s.l., and in three main geographical aspects (north, east and west), 30 ‎circle sample plots with 500 m2 were selected in wild cherry habitats. Characteristics of wild cherry such ‎as physiographic features, diameter at breast height (DBH), origin, trunk quality and canopy diameter with a diameter ‎of more than 6 cm were recorded in each sample plot. Also, soil samples were taken ‎to determine some soil properties. Results showed that the DBH of trees in the altitude range of ‎‎1000-1500 m.a.s.l. is significantly higher than the altitude range of 1500-2000 ‎m.a.s.l. It can be concluded ‎that wild cherry stems have higher growth potential in terms of elevation class at low altitudes ‎and in terms of soil conditions in deep soils and high drainage with medium moisture retention ‎capacity. It was also found that the mean of both DBH and crown diameter and the density of wild cherry in the northern ‎and eastern aspects are higher than in the western aspect. Generally, wild cherry in this region prefers the northern and eastern slopes.‎Analysis of Relevance and Redundancy (RDA), Arasbaran, elevation, geographical aspect.

Prosopis cineraria (L.) druce and Ziziphus spina-christi (L.) Desf. are important species of Sahara-Sindhi vegetation. While being native, they have good adaptability, growth and regeneration. This study was conducted to estimate the amount of groundwater required for the sustainability of Z. spina-christi and P. cineraria natural forests in the watershed of Faryab county in Kerman province, Iran. First, using Google Earth images, networking establishment of ninety plots of 100 m2 in one-hectare networks, the average number of Z. spina-christi and P. cineraria trees were counted. Then, using the minimum water requirement of trees, estimated based on lysimetric studies, water consumption of Z. spina-christi and P. cineraria trees in the area was calculated. Using the MODFLOW model, the groundwater balance situation in Faryab plain aquifer for 2017-2018 was calculated. Having the volume of water consumption of Z. spina-christi and P. cineraria in the region, water balance and aquifer storage coefficient, the impact of the forests on groundwater of Faryab plain was calculated. The results showed that the average number of P. cineraria trees is 250 individuals and Z. spina-christi tree stands are 30 individuals per hectare. The results of the study of water balance and groundwater aquifer show a volume deficit of 25 million cubic meters of the reservoir and a 26-meter drop in groundwater level over the past two decades. According to the water balance calculated, the uncontrolled extraction of water by agricultural wells, which is about 160 million cubic meters per year, has caused such a decline in the region. Considering the importance of Z. spina-christi and P. cineraria trees for this ecosystem as the main species, the water right of this forest was estimated to be 2.6 million cubic meters per year in the planning of water resources in the Faryab plain.

Oak trees are hosts of diverse gall-inducing parasites, but the information about the leaf gall is poorly understood. This study aims to examine the weight of leaf galls on oak trees (Quercus brantii Lindl.) in different crown directions with different growth forms (high-forest and coppice) on different geographical slopes in healthy and dry stands of Kohgiluyeh and Boyer-Ahmad province, Iran. For this purpose, two sample plots with a one-ha area involving decline traces of trees (dry) and two sample plots without dieback (control) on the northern and southern slopes in forest sites of Boyer-Ahmad and Dena counties of Iran were selected by field survey. After recording the quantitative variables (DBH, mean diameter of sprout-clump, height and canopy cover), we collected 20 leaves from each direction of the crown of each tree sampled. In the laboratory, the galls were removed from the leaves and weighed. The results showed that there was no statistical significance between the different crown directions of the sample trees in both growth forms, although, in most sites, the northern direction of the trees had more galls. Leaf samples from the south decline site were found to have significantly more gall weight than samples from the other sites in both growth forms. Also, high-forest trees had significantly more leaf galls on their leaves than the coppice trees did. Monthly average temperature and altitude seem to be two determining factors in leaf gall development of the oak trees.

Integrated forest ecosystem management plays an important role in controlling degradation and balancing its various functions for the sustainable use of all available capabilities. In this regard, beekeeping is one of the most suitable multiple uses of the forest. The purpose of this study is to introduce a fuzzy multi-criteria Evaluation approach (F-MCE) to determine the forest's capability for beekeeping and compare it with the conventional non-fuzzy approach. In this regard, beekeeping capability in 16825 hectares of Zagros forests in Kabirkouh region of Ilam province, Iran was evaluated by the two approaches in four classes and the results were compared. Evaluation criteria were the same in both approaches and included the percentage of the canopy of plant attractiveness classes, flowering period, slope, air temperature, relative humidity, prevailing wind speed, and access to road and water. The weight of the criteria was determined using the Analytic Network Process (ANP). In F-MCE, the values of the criteria were determined using fuzzy membership functions and the criteria were combined by the Weighted Linear Combination (WLC) method. Then, beekeeping capability was digitally evaluated using the Multi-Criteria Evaluation method (MCE). The results showed that 40% of the area of beekeeping classes differed in the two evaluation approaches and the main part of this difference (35.6%) is related to the areas that were evaluated in the F-MCE approach in the good class (S1) and in the traditional approach in Moderate class (S2). This difference in results can be attributed to the different methods used in F-MCE in which the adverse effect of boolean and subjective criteria evaluation in the traditional method is avoided through their digital evaluation with fuzzy logic.

Changes due to the introduction of non-native species are very important, especially in arid and desert areas. Because protection and regeneration in these fragile ecosystems are difficult. Soil is the basis of ecosystems. The effect of introduction and establishment of non-native species can be evaluated by sensitive indicators such as soil enzyme activities. The activity of acid and alkaline phosphatase, urease, dehydrogenase, and invertase enzymes were investigated as well as soil physicochemical properties (the percentage of soil moisture, organic carbon, total nitrogen and available phosphorus) under and outside the canopy of Prosopis cineraria (L.) Druce and P. juliflora (SW.) DC.). Soil sampling (in total, 24 samples) was done randomly from a depth of 0-30 cm in a natural habitat of the two species located in Assaluyeh, Bushehr province, Iran. The statistical analysis showed the sampling location had a significant effect on activities of the all studied enzymes (p< at least 0.05). These enzymes were more active under the canopy of the sample trees. Under the canopy of P. juliflora, enzyme activities did not differ significantly from that of P. cineraria. The interaction of species and sampling location was only significant in alkaline phosphatase enzyme activity (p<0.01). Due to the lack of harmful effects of P. juliflora as a non-native species on soil enzymes activities and also it's a very fast growth, it seems that with the application of scientific and correct management, P. juliflora in de-desertification and forest regeneration programs in Sahara-Sindhi habitats in Assaluyeh should be noticed.

It seems that in different geographical conditions, according to the existing culture and facilities, the type and method of exploitation are different, which will affect the quantity and quality of exploitation and ultimately, the destructive or protective role of harvesting products on forests and pastures. The purpose of this study was to investigate the dual revenue-protection role of exploitation of non-timber products of Shabankareh’s forest in Ravansar County in Kermanshah province, Iran. The research was quantitative, and in terms of data collection method, it was descriptive survey research. The study population consists of 111 householders in Shabankareh village. The results showed that the role of non-timber products in the livelihood of foresters is significant and the income is 6485096.77 Tomans annually, which has a complementary role to improve the livelihood of users. Also, results showed that the average exploitation rank of villagers who harvest in the form of groups was 57.75, which is higher than villagers who were personally exploited. According to the findings of the factor analysis technique, observing the correct principles of exploitation with 15.19% of the total variance, managing and monitoring the principles and appropriate time of exploitation with 14.71% and increasing sensitivity to the forest situation with 8.37% of the total variance, have the greatest impact on the protective role of exploitation. Results showed that the Exploitation of non-timber product is a more destructive and less protective role in Shabankareh’s forests. In general, it can be said that by modifying the exploitation structures, the protective role of exploitation of non-timber products can be strengthened.

The purpose of this study was to monitor changes in the structural characteristics of a pollarded oak forest in Baneh county of Kurdistan province, Iran. Fifty-nine permanent sample plots were recovered for 14 years (2005-2019). In each plot, the diameter at breast height (dbh) for all trees (dbh ≥ 5 cm) was measured. Woody species less than 5 cm in dbh were recorded as regeneration in two height classes less than and greater than 2 meters by species and form (coppice and seedling). Total height and crown area for two trees in each sample plot (i.e., the nearest tree to the center of the plot and the largest tree in terms of dbh in the plot) were measured. The results showed that the difference between the beginning and the end of the studied period was significant in terms of the distribution pattern of trees in diameter classes (p<0.01); while there was no significant difference in the distribution pattern of trees in the total height and canopy area classes. The average annual increment of diameter, height and crown area in oak trees (excluding species) was 2.41 mm, 12.59 cm and 0.73 m2, respectively. A comparison of the current diameter distribution curve with the expected diameter distribution showed that the number of trees in diameter classes lower than 12.5 cm was less than the expected value, indicating poor regeneration. In order to reveal the consequences of pollarding as a traditional silvopastoral system and to make appropriate management decisions in order to improve the condition of pollarded oak forests, the use of permanent sample plots is suggested as a suitable method for studying the changes in structural indices of these forests.