نشریه بوم شناسی جنگل های ایران
پیاپی 12 (پاییز و زمستان 1397)

Natural regeneration ensures the survival of forest stands and sustainable forest development. The present study was conducted to investigate the natural regeneration of Persian oak (Quercus macranthera fisch. & C.A.Mey. Ex Hohen) stands in Arasbaran protected forest. Measurement of the frequency of standard and coppice regenerations was carried out in one-hectare square plots (100 × 100 m) in the habitat of this species in three levels of elevation including 1200-1400, 1400-1600 and 1600-1850 m above sea level (3 sampling plot in each altitude). The frequency classes were recorded in three groups: seedling (height≤30 cm), small sapling with a height between 30-130 cm and large sapling with a height more than 130 cm differentiated by regeneration source, including standard and coppice regeneration and species name. The results showed that the both of standard and coppice regenerations were the most frequency in large sapling with a height of more than 130 cm. The altitude of 1400-1600 m a.s.l had the most frequency percentage in all species regeneration. In addition, with increasing altitude, the amount of coppice regeneration decreased and the frequency of standard regeneration increased. The frequencies of standard and coppice regenerations have significant difference according to two-way ANOVA at different altitudes, different groups and different species. Based on the results of this study, the access to the forest stands and the increase in the destruction by humans and livestock reduces the frequency of species regeneration and expands the coppice regeneration. As the altitude increases and the access reduce, the amount of standard regeneration will increase. Therefore, conservation activities can help to reduce the degradation of the natural regeneration area.

Oak decline is an eminent factor, which has a significant role in degradation and change in Zagros forests. The goal of present study was to assess the crown surface area of oak trees in Sarableh forests, Ilam province. For this purpose, permanent sample plots were used. Eighty sample plots with 10 Ar area were applied based on systematic-random method in a 150×200 survey network in 120 ha. The crown diameters and oak decline were measured. Oak decline was classified in five classes (very high, high, medium, no decline). The inventory was conducted in 2012 and 2014. The Mann-Whitney test was used to compare the oak decline in two inventory times. The results showed that the trees in very high and high decline classes (total of two classes) were 13.6% in 2012 and it is increased to 25.4% in 2014 (to be an 11.8% increase). The changes in forest decline were significant at decline classes (P≤0.01). The highest oak decline was observed in two m2 crown area and the maximum healthy trees were found in 14 m2 crown area. Our result revealed that trees with small crown area are more engaged by forest decline. In order to managing the forest engaging to oak decline in Ilam province and the rehabilitation of these forests , it is recommended the trees with small crown area (up to seven m2) should be more considered in terms of forest rehabilitation and tending.

This study investigates the role of man-made disturbance on on nitrogen and phosphorus nutrient storage by herbaceous species in Gall Oak stands of Lorestan province. In order to do this study, two sites with the same physiographic and ecological conditions and different land uses were selected. Multiscale sampling plots were used randomly in each site to collect data on forest floor vegetation, trees and soils. Richness and biodiversity indices, generalist species, herbaceous biomass, nitrogen and phosphorus content of the plant tissues and nutrient storage were compared in two sites. Results showed significant differences in the two studied sites, between species richness, the number of herbaceous species, Margalaf richness and Shannon-Weiner diversity indices, above-ground and below-ground biomass. Also the above-ground and below-ground biomass were greater 43.7% and 35.3% respectively in the protected forest. Based on the results more amounts of nitrogen and phosphorus was stored by herbaceous species in protected forest. Also more native species and surface soil fertility improvement in the protected site revealed that conservation programs led to better environmental conditions and provide suitable conditions for ecosystem resilience. Also, more amounts of nutrients stored by herbaceous species in protected forest indicates that these plants plays important role in the storage of nutrients in the ecosystem. As the amounts of nutrients was less in the disturbed forest.

In order to study the effect of altitude on some quantitative and qualitative characteristic of Populus deltoides in Mazandaran province, three sites were selected with elevations between 150 and 1200 m above sea level in Sari city. In each site, some tree traits such as diameter at breast height, total height, basal area, volume, form factor and qualitative variables including trunk health, crown shape and trunk form were measured and evaluated and quantitative and qualitative characteristics of trees in three sites were compared using one-way ANOVA and Kruskal Wallis tests. Results showed that the altitude had significant effects on qualitative and quantitative characteristics of Populus deltoides trees and trees in lower altitude ranges (150-300 m) had a higher diameter and volume growth than trees in higher altitudes. According to results, the highest diameter (27.83 cm), height (21.13 m), basal area (0.046 m2), volume (2.11 m3) and the highest number of trees with cylindrical trunks were observed in Mahdasht. Tress in Pahnekola had the highest form factor (0.99) and with symmetrical crowns. According to results of this study, it can be concluded that planting with Populus deltoides trees in lower altitude ranges can increase the qualitative and quantitative characteristics of such trees and provides a suitable approach for supplying wood for wood-based industries.

Vegetation is one of the most important components of ecosystem, which plays an important role in protecting soil and preventing its rise. So, monitoring and evaluating its changes in planning to control the dust storm is effective. The purpose of this study was to investigate the changes of vegetation in the internal and external dust storm sources of Kermanshah province and dust extension areas. For this purpose, horizontal visibility data were obtained from the meteorological administration of Kermanshah in the statistical period 2005 to 2015. In 2008 and 2009, as well as in the months of May, June and July, due to the most frequent occurrence of days with dust were the basis of study. In the next step, the most important events of dust in the years and months were selected based on two criteria of minimum horizontal visibility and maximum duration of continuity and the MODIS satellite image (MOD02) was obtained for them. The BTD method was used to detect dust storm. Then vegetation changes were evaluated using MOD09 Q1 MODIS and NDVI index in three year intervals and in good, moderate and poor vegetation categories. The results of this study showed that in 2006 the area of good vegetation class in the external and internal dust storm sources was 1.8% and 28.25%, respectively, but in 2015 the area of this class decreased in both external (0.87%) and internal (18.62%). In general, considering the important role of vegetation in soil conservation, it can be taken with the conservation, regeneration and extension of the vegetation, especially in areas where the results of this research have been reduced, have taken an effective step in controlling the dust storm.

Participatory forest management, as a model for sustainable forest development, prepares local people to play an effective role in their fate and they enable to participate in the process of sustainable forest development. Present research looks to the gap of between the current status and the ideal status of the forest Bankoul area as a fundamental concern. So, this research has done with the aim of formulating of management participatory mechanisms of the mentioned area. The method of research is a descriptive and analytical method so that with the help of PRA various tools, the needed information was collected from the local stakeholders. Then, using the SWOT model, internal factors (weaknesses and strengths) and external factors (opportunities and threats) were identified. For evaluating and weighing of Internal Factors (IF) and External Factors (EF) used from the process of Quantitative Strategic Planning Matrix (QSPM). Internal factor matrix with score of 3.07 shows that the studied area has more strengths than weaknesses. External factors matrix with score of 2.94 shows that the mentioned area has more opportunities than threats. The results indicate that the studied area in the strategic planning table places in an aggressive conditions (SO mechanisms) and based on analysis of QSPM, mechanisms of SO are the best mechanisms for participatory management of the forest Bankoul area. Therefore, in the studied area, if we want to move towards mechanisms of participatory management, we must give priority to aggressive mechanisms.

Herbal Medicines are valuable natural resources that nowadays absorbed the attention of developed countries. Also this plants are using as raw materials to produce Low-risk and potent drugs for humans. One of these valuable species is the Cionura erecta shrub, distributed in a limited area of our country. The aim of this study is investigating the chemical composition of the essential oil of this species. For this purpose, samples from leaf, stem and fruit were collected from Chahar-tagh region of Chaharmahal and Bakhtiari province and essence were extracted by Clevenger machine. In order to identify the essential oil composition, the gas chromatograph (GC) and gas chromatograph attached to mass spectrometer (GC-MS) were used to compare the inhibitory and mass spectrometry indices. The results showed that the essential oil of this species has valuable compounds such as Eugenol, Caryophyllene oxide, Cedron-9-one and Alpha cadinol, which are widely used in industry and pharmacy and pest control. In this study, 23 main chemical compounds were identified totally, that Cedron-9-one and Eugenol Had the highest percentage among identified compounds. Also, the results of this study showed that the essential oil of this species is a rich from the mineral elements including: phosphorus, magnesium, iron, copper, sodium and zinc.