Sustainability of wave energy resources in southern Caspian Sea

This study aims to evaluate the wave energy potential and its spatial and temporal variations in the southern Caspian Sea. For this purpose, SWAN model was used to hindcast wave characteristics for 11 years. The wave energy assessment was conducted in four nearshore stations in order to assess the feasibility of wave energy harvesting and locate the most appropriate station. Assessment of seasonal and monthly variations of the mean and maximum wave powers showed that the central station contains the highest values, especially in November; while the north-eastern station has the lowest values with the highest variation of directional distribution of the wave power. Moreover, the seasonal and monthly variability indices indicate a relatively stable wave condition in all stations. The total and exploitable storages of wave energy were also higher in the central station. Therefore, it was concluded that the central station is the most appropriate location for wave energy harvesting. Furthermore, the inter-annual variations of the mean wave power illustrate no significant long-term change in wave power in the southern Caspian Sea. Therefore, considering the relatively stable condition and comparable exploitable storage of wave energy, this area can be a suitable location for developers

Temporal-spatial variation of wave energy and nearshore hotspots in the Gulf of Oman based on locally generated wind waves

This study aims to assess the wave energy at five coastal stations in the Gulf of Oman using the time series of locally generated wind waves obtained by numerical modeling for 11 years. For this purpose, the spatial, seasonal, monthly, directional, inter-annual of wave energy and power were investigated. The spatial distribution shows that the wave power increases towards the Indian Ocean and the highest mean wave power is located at the eastern station in all seasons. In addition, monthly mean wave power is highest during July and August while the monthly maximum wave power is highest during February at all stations. The ratio of monthly maximum to mean wave power is also the lowest during May to August. Moreover, Monthly Variability Index is the highest in west of the domain where there is no significant wave power potential. In addition, annual wave power as well as total and exploitable wave energies increases from west to east, where the dominant waves propagate from the south, and the exploitable wave energy is approximately 20 times greater than of the central stations

Arbuscular mycorrhizal fungal symbiosis with Sorbus torminalis does not vary with soil nutrients and enzyme activities across different sites

Effects of soil chemical properties on arbuscular mycorrhizal fungal (AMF) symbiosis with wild service tree (Sorbus torminalis L. Crantz) were examined for study the rates of root colonization at three forest sites: Kheiroud, Lalis, and Takrin in northern Iran. Soil characteristics including pH, available phosphorus (P), potassium (K), organic matter, total nitrogen, acid and alkaline phosphatase activities, CaCO3, spore density (SD) and AMF colonization of soil and root samples were analyzed. The study sites were investigated in spring and autumn to highlight the effects of soil chemical properties on AMF statues for better nurseries and reforestation management of this rare tree species in forests. Changes in soil pH, P, K, organic matter, total nitrogen, acid and alkaline phosphatase, CaCO3, SD, and AMF colonization of soil and root samples were analyzed at the study sites. K, pH, root colonization, SD and acid phosphatase activity showed no significant differences among sites in spring and autumn, while total nitrogen, P, organic matter and alkaline phosphatase activities showed significant differences among sites and seasons. AMF colonization rates were more than 51% and 32% of roots in spring and autumn, respectively. No correlation between root colonization and soil chemical parameters in spring and autumn were detected. There was no correlation between percentage of AM root colonization and SD nor other soil parameters in spring and autumn. SD and CaCO3 were significantly negatively correlated in spring and autumn. Despite differences in soil characteristics, the results showed that SD and root colonization were not significantly different among the sites. They also showed that wild service trees had strong symbiosis with AMF, while soil properties might not have a significant effect on this symbiosis. Therefore, colonized seedlings can be considered as an appropriated method for reforestation and conservation of this rare tree species

Climate change impact on wave energy in the Persian Gulf

Excessive usage of fossil fuels and high emission of greenhouse gases have increased the earth’s temperature, and consequently have changed the patterns of natural phenomena such as wind speed, wave height, etc. Renewable energy resources are ideal alternatives to reduce the negative effects of increasing greenhouse gases emission and climate change. However, these energy sources are also sensitive to changing climate. In this study, the effect of climate change on wave energy in the Persian Gulf is investigated. For this purpose, future wind data obtained from CGCM3.1 model were downscaled using a hybrid approach and modification factors were computed based on local wind data (ECMWF) and applied to control and future CGCM3.1 wind data. Downscaled wind data was used to generate the wave characteristics in the future based on A2, B1, and A1B scenarios, while ECMWF wind field was used to generate the wave characteristics in the control period. The results of these two 30-yearly wave modelings using SWAN model showed that the average wave power changes slightly in the future. Assessment of wave power spatial distribution showed that the reduction of the average wave power is more in the middle parts of the Persian Gulf. Investigation of wave power distribution in two coastal stations (Boushehr and Assalouyeh ports) indicated that the annual wave energy will decrease in both stations while the wave power distribution for different intervals of significant wave height and peak period will also change in Assalouyeh according to all scenarios

Dead wood characteristics influencing macrofungi species abundance and diversity in Caspian natural beech (Fagus orientalis Lipsky) forests

Aim of study: This study aimed to examine the dead wood inhabiting macrofungi communities occurring on dead beech and hornbeam trees in Caspian forests. Area of study: The Kheiroud forest in the north of Iran. Material and Methods: Data from 205 sampling dead tree were analyzed by means of Generalized Linear Models (GLM) to test the effects of decay stage, DBH, Length or Height on macrofungi diversity. Additionally, tree species, dead wood size, log position, decay stage were used as predictor factors for the number of sporocarps species (NSS) as a fungal species richness and diversity in each dead log using analysis of variance Main results: The number of sporocarps species (NSS) varied in different dead wood size and decay classes. The different stages of decay and the different size classes of dead wood had significantly different species richness of macrofungi. Deadwood in the high-decayed stages contained the highest diversity of fungi. Most of fungi identified on both logs and snags belonged to Basidiomycetes and Ascomycetes. The highest value for richness and evenness indices calculated in large diameter dead wood in decay class III. The results indicated the size and decay class of dead wood describe the greatest variance of the model that means the highest number of sporocarps species inhabited on the large dead wood in advanced stage of decaying. Research highlights: Macrofungi diversity varied significantly across pieces of dead wood with downed logs, larger pieces, and wood in later stages of decay having the highest macrofungi diversity

Dead wood characteristics influencing macrofungi species abundance and diversity in Caspian natural beech (Fagus orientalis Lipsky) forests

Aim of study: This study aimed to examine the dead wood inhabiting macrofungi communities occurring on dead beech and hornbeam trees in Caspian forests.Area of study: The Kheiroud forest in the north of Iran.Material and Methods: Data from 205 sampling dead tree were analyzed by means of Generalized Linear Models (GLM) to test the effects of decay stage, DBH, Length or Height on macrofungi diversity.  Additionally, tree species, dead wood size, log position, decay stage  were used as predictor factors for the number of sporocarps species (NSS) as a fungal species richness and diversity in each dead log using analysis of varianceMain results: The number of sporocarps species (NSS) varied in different dead wood size and decay classes. The different stages of decay and the different size classes of dead wood had significantly different species richness of macrofungi. Deadwood in the high-decayed stages contained the highest diversity of fungi. Most of fungi identified on both logs and snags belonged to Basidiomycetes and Ascomycetes. The highest value for richness and evenness indices calculated in large diameter dead wood in decay class III. The results indicated the size and decay class of dead wood describe the greatest variance of the model that means the highest number of sporocarps species inhabited on the large dead wood in advanced stage of decaying.Research highlights: Macrofungi diversity varied significantly across pieces of dead wood with downed logs, larger pieces, and wood in later stages of decay having the highest macrofungi diversity. Keywords: Caspian forest; coarse woody debris; down woody debris; Iran

Effect of cutting time, cutting length and hormone on rooting and germination of Vitex pseudo-negundo (Hausskn.) Hand-Mzt. cuttings

Vitex pseudo-negundo (Hausskn.) Hand-Mzt. is a shrub that is height of about 1-2 meters. To study vegetative propagation of Vitex pseudo-negundo experimental was conducted using a‌ 6 × 3 × 2 factorial design based on completely randomized design with 4 replications and 30 cuttings per treatment in Behbahan municipalities' greenhouse. The experiment factors included: Cutting time at 6 levels (22 December and 5 January, 21 January and 4 February, 20 February and 6 March), Cutting length at 3 levels (15, 20 and 25 cm) and NAA hormone at 2 levels (with hormones and hormone-free). Results showed that the cuttings taken in 21 January, 20 February and 6 March have the highest rooting and germination percent and root number. The highest (rooting and germination percent) and (root number and root dry and fresh weight) were observed in length cuttings of 15, 20 cm and 25 cm respectively. The interaction effect of hormone and cutting time and cutting length, indicator being more dry weight, fresh weight and root diameter in cuttings with hormone taken in 20 February with a length of 25 cm. The use of hormone has the negative effect on rooting and germination percent and root length. In this study, the best result was achieved for cuttings taken in 20 February, with a length of 25 cm and without the use of hormones

Primary study of diameter effect on the ability of stump sprouting of Lebanon oak (Quercus libani Oliv.) in northern Zagros forests (case study: Armardeh, Baneh)

This study was carried out in order to compare the number of produced sprouts in Lebanon oak (Quercus libani Oliv.)  tree after cutting among dbh classes in northern Zagros forests. 3 dbh classes including 25-35, 35-45 and >45 cm were compared in respect of number of produced sprouts. 5 sites in Armardeh forests were selected and results of study analyzed by random complete block design. 3 Lebanon oak trees were cut in each diameter class and in each block. The 45 cut trees were fenced in early spring 2007 individually. Data were collected two times in June and September. Results showed that 35-45 cm dbh class had the most number of sprouts (with 101 and 81 sprouts in June and September, respectively). Number of sprouts in 35-45 cm dbh class was significantly different from others in September, while no significant difference was found in number of sprouts between June and September. Mortality rate of sprout among dbh classes was not significantly different. However, linear regression trend between number of June sprout and died sprouts until September showed that mortality increased when number of June sprout increased. Since sprouting depend on positive and negative effects of stump size, balance point of these effects was introduced as optimum diameter for sprouting, which was between 35-45 cm dbh range in this study. Future investigations should be focused on finding the balance point (or range), more precisely

Redescription of two species of Oplitis Berlese (Acari, Mesostigmata, Oplitidae) from Iran

Two new species records of Oplitidae, Oplitis exopodi Hunter & Farrier, 1975 and Oplitis sarcinulus Hunter & Farrier, 1976 are redescribed based on Iranian specimens from leaf-litter forest in Mazandaran province, northern Iran. A key to the Iranian species of Oplitis is presented

Evaluation of disturbance and spatial attribute on regeneration using structural equation modeling (Case study: Khyrud forest- Nowshahr)

Effects of anthropogenic disturbances through livestock grazing, wood harvesting, and direct utilization by local people plus spatial heterogeneity on the regeneration of forest tree species and forest health have been recognized worldwide. In this research, effects of disturbances and site features (Aspect, slope percent, altitude, and soil) were investigated on tree species regeneration in Khyrud forest-Nowshahr, north of Iran. Indicators pertaining to saplings, large sapling and trees were measured in 100 plots, 10 m2 each, for disturbance and spatial constructs of Structural Equation Modeling- Partial Least Squares method. Results showed disturbance has a significant (α = 0.01) effect on regeneration. Effects of sapling on large sapling and large sapling on tree constructs were significant (α = 0.01), too. The moderating effect of spatial construct on disturbance to sapling path (α = 0.01) and disturbance to large sapling path (α = 0.05) was significant. We conclude that disturbance and spatial attributes have high influence on sapling and large sapling in the study area, respectively which affect trees indirectly