مجله پژوهش و توسعه جنگل
سال دوم شماره 1 (بهار 1395)

In this study some characteristics of an unmanaged natural stand were measured and surveyed in two sampling periods as long as eight years in Kheiroud forest. Results showed that about 9.7 percent of all trees was fallen, 6.5 percent of trees were dried, 2.6 percent of all trees were embowed and crown of 1.6 percent of trees was broken during the period. Also the most fallen trees were occurred in low diameter categories (10 and 20 cm). Slenderness coefficient studies in the first period suggest the possibility of falling the trees in the future. Results showed that there is a negative significant correlation between height of crown and total height in first period and a positive correlation between height of trunk and total height. These relations in second period are inversed. In the surveying of relationships between trunk with branches and without branches in all specie, it is determined that trunk without branches height in relation to trunk with branches is more obvious. The number of fallen and dried trees in the stand and the situation of the trees in diameters classes imply on needing of stand thinning. Otherwise, continuing of the stand destroying and increasing number of unhealthy trees will not be avoided.

Understanding and our knowledge about mixed beech stands development play key role in managing forest stand in the close to nature ways. There are differences in amount and quality of coarse woody debris reported from beech stands in the north of Iran. This research try to answer this questions: how amount and quality of coarse woody debris affected by stand development stages? So 30 one hectare sampling plots randomly were chosen in main three stand developmental stages and all coarse woody debris had been measured. Results showed that the volume of CWD followed the general “U-shaped” temporal trend: the highest in the Volume transition stage (42.2 m3 ha-1), lowest in the volume accumulation (12.8 m3 ha-1) and intermediate in the Volume growing up stage (27.8 m3 ha-1). Amount of oriental beech coarse woody debris was (log, snag and stump) significantly higher in three stages. Amount of beech volume, logs, size class III and decay class I and IV significantly differ among the three stages. Our results revealed that stand development have effect on the distribution of CWD among three stages.

Mulberry is used for planting development. This tree is one of the important species that planted in the Mobarakeh Steel Complex. This tree dieback has been a main managerial problem in recent years in the company. Environmental stress is one of the most important factors that influencing on species dieback. Absorption of heavy metals as an environmental pollutants, nutrient absorption, plant pigment and proline can determine the impact of stress on the occurrence of this phenomenon. The 2000 m2 plot was built in each area that planted by this species. Leaves complex sample of 5 trees were collected of healthy and unhealthy trees to compare of elements concentration. The results showed that the uptake of heavy metals including lead, mercury, cadmium and nickel in the leaves of unhealthy trees was higher than healthy trees, but the amounts of these elements were not toxicity in unhealthy trees. Absorption of macro and micro nutrients such as calcium, potassium, nitrogen, manganese, magnesium, iron, copper and zinc in the leaves of healthy trees was more than unhealthy leaves, but the amount of sodium and chlorine in the leaves of unhealthy trees were rather than healthy trees.This condition was indicative of salinity stress in the habitat. Water sources also indicate this phenomenon. Lack of soil fertility also created many problems for power plants. Soil fertility stresses was extended dieback of trees.

Cornelian cherry grows naturally in Arasbaran forests and a plenty amount of its fruit have annually been exploited in traditional manner. This study aimed to determine the cornelian cherry fruit production and the relationship between vegetative characteristics and amount of fruit production for three consecutive years. For this purpose, as cornelian cherry habitat, the forest stand by 50 hectares in Kalaleh village in North West of Iran (Arasbaran region) was selected. To determine cornelian cherry fruit production per hectare, the number of cornelian cherry stems per hectare was determined along 15 transects with distance of 100 m apart from each other. To estimate fruit product, a number of 45 individuals of cornelian cherry were selected and then marked along transects with randomized systematic method. Then, for three years, similar vegetative characteristics: total height (m), crown height (m), crown diameter (m), diameter at breast height (mm), diameter at collar (mm), number of coppice shoots and fruit product (gr) were measured annually. Mathematical model regression to determine relationship between the measured vegetative characteristics and fruit production per stem were established. Then Fruit product per hectare was calculated given the number of stems per hectares. According to survey results, the mean number of Cornelian cherry was calculated 530 individuals per hectare. Average fruit production in three consecutive years, respectively 446.97, 318.69 and 253.37grams for each trees. Also was found that three characteristics: canopy diameter, diameter at collar of the main stem and number of coppice shoots were significantly correlated with the fruits product. These three characteristics can be used as crucial factors in the management and silviculture operations of the forest in order to increase the fruit production.

The objectives of this study were determining growing season as well as the relationship between width of growth rings of the Iranian oak and temperature and precipitation. In this study, 12 healthy oak trees (Quercus brantti) were selected and disk samples were taken at the diameter of breast height. High quality image were taken from all of the disks, after preparation. Cross dating was performed among samples and the chronology provided by ARSTAN. Relationship between annual growth rings and climate factors determined by Pearson correlation coefficient. Our result indicated highly significant positive correlation between annual growth ring and average monthly temperature February and July. Also the results revealed that there was non-significant negative correlation between growth and precipitation in studied months. Existence of positive correlation between growth and climate factors (temperature and precipitation) in March, represented that these two factors could help tree growth in early growth season.

The main objective of this study was to estimate the effect of decline disturbance on canopy distribution of coppice oak trees in central Zagros region. For this purpose one similar stand with (32ha) in central Zagros (Dadabad in Lorestan province) was selected. Canopy of declined trees was recorded before and after cutting using 100% inventory method. Then Beta, Jonson, Weibull, Gamma, Normal and Log-normal distribution functions were applied. The results of goodness of fit tests suggested that Gama, Jonson and Weibull functions are fitted for introducing Canopy of woody stems in field, respectively, are suitable for Dadabad region. There was difference between before and after decline disturbance based on using statistical distribution. The results of goodness of fit tests for after decline suggested that Weibull, Jonson and Gama functions are fitted for introducing Canopy of woody stems is suitable for Dadabad region. Other distributions had not ability to evaluate this characteristic. Influence of decline in this region was in a way that does not impact on some categories of cover in the same way, so the canopy fitting pattern region has a significant impact. Scanning fitting canopy Zagros forests in different classes and in different time steps, the status of these forests in terms of ecosystem degradation and the process sequence, which in educational management problems and has many applications.

Species diversity, effect of edaphic mesostigmatid mites and their feeding habits on natural equilibrium of soil creatures is very important and of indices of changes in ecosystems. In this study, our goals were collecting and evaluating of diversity of soil specimens in four sights of Arasbaran forests in summer 2013. Biodiversity indices of Shannon, Simpson and Brillouin in addition to evenness index of Simpson, Camargo and Smith-Wilson calculated by means of ecological methodology 6.0 software. Our results revealed that the maximum relative abundance belongs to Veigaia nemorensis (Koch, 1836) with 11.54% andVeigaia planicola (Berlese, 1882) with 8.34% both from Veigaiidae family and minimum belongs to Sejus sp. from family sejidae with 0.17%. Maximum rate of Shannon’s and Simpson’s diversity was respectively 4.61 and 0.97 in Kalaleh area, with maximum collected species number rate of Simpson’s evenness index also belongs to this area with 0.65 percent. The high frequency of mites of family Veigaiidae can be attributed to their strength of predatory and fauna richness in the soil.