Iranian journal of Forest
Year:2019 | Volume:10 | Issue:4 |Papers Count:11

One of the essential characteristics of fine-grain soils is the plasticity or Atterberg limits of them that directly are used in classification and prediction of mechanical properties and soil behavior. The aim of this study was to investigate the effect of different treatments of drying the soil sample on the plastic and liquid limits, type of measurement apparatus that used to determine liquid limit and the impact of these factors on the Unified soil classification. Also in this study, the results of the one-point method of Casagrande were compared with the usual multi-point method. For this purpose, soil samples were taken from three different forest types and five different depths in each type. The results showed oven drying of samples resulted in underestimation of the Atterberg limits and a different soil class in 33 percent of samples. Comparing the results of Casagrande and cone penetration apparatus to determine the soil liquid limit showed that the results were similar in both methods and only in one sample, there was different soil class. However, the cone penetration method is faster and requires less user experience. Finally using one-point method to determine the liquid limit, did not show difference with multi-point method and liquid limit differences between the two methods is about 0. 26 percent; Which did not lead to significant displacement on the borders of Casagrande plasticity chart. Thus, in the case of sufficient experience and high number of samples, is recommended as an alternative to the usual multi-point method.

Due to the increasing damage caused by wood-boring pest of Platanus orientalis in the urban environment, it is required to analyze the different preventive care for this species. This study aimed to investigate the performance of various traps for mass trapping of sycamore wood borers in Karaj city for two years. Four different experimental stations were selected across the city to install the required traps. Each station was instrumented with nine light traps (i. e. white, yellow, and black light), six sticky traps and six bucket traps (i. e. white, yellow, orange, red, blue, and green) and 10 cylindrical traps. Pest collection was started in May 2015 and continued till October 2016 at weekly intervals. The data were statistically analyzed using GLM procedure by using SPSS software ver. 16. Trapped samples include three families including Buprestidae, Cerambycidae and Scarabeidae. The results indicated no significant difference between bucket trap (1. 9), sticky trap (1. 38) and cylindrical trap (2. 55) in wood borer absorption, but the wood borer absorbed by light trap (27. 33) was significantly higher than those observed by other traps. Within the light traps, the black light (42. 33) and the white light (12. 67) absorbed the highest and the lowest amount of wood borers, respectively. Finally, it could be suggested that the most appropriate trap for mass trapping of sycamore wood borers is light trap. Also, white and orange colors are more efficient in attracting the sycamore wood borers.

This study was carried out to understand the dynamics of Lebanon oak coppice regeneration. In this regard, the effect of thinning on both individual sprouts and stools as well as estimation of sprout biomass using allometric equation were investigated. 45 Lebanon oak trees with different sizes (i. e. DBH from 25 to 65< cm) in five sites were cut and individual stumps were fenced to monitor the sprouting behavior. In the second year after the cutting, light (six sprouts reserved in each stool) and heavy thinning (three sprouts reserved in each stool) were conducted in two third of stools equally and the rest un-thinned ones were considered as control. Data analysis, five years after thinning, showed that the most portion of individual biomass allocated to main stem (57. 4%), main branches, leafs and fine branches, respectively. On average 42% of total fresh mass of sprouts were reduced due to water loss in drying process. Analysis of variance indicated that stump size has no significant effect on biomass of individual sprout either stools while it was significantly different among sites. Comparison of thinning treatments and control one showed that light thinning resulted in sprouts with the most biomass while no significant difference was observed between heavy thinning and un-thinned. Using a basic power model, allometric equation was fitted to estimate the sprout biomass. Based on regression analysis as well as derived indicators (R2, STDEV, RMSE, rRMSE and nRMSE) and models validation by leave one-out method, the collar diameter was found as the best explanatory variable in young sprouts biomass.

Among the soil forming factors, climate is one of the most important factors that determines the soil physical and chemical properties. This research aims at studying the effect of different climates in Ilam Province on soil chemical and physical characteristics of Iranian oak forest (Quercus brantii Lindl. ) including high and coppice growth types. Soil samples were randomly taken at 0-20 cm depth under each growth types. According to the results, the climate significantly affected all soil chemical and physical characteristics (p < 0. 01) which indicates the importance of climate effect in three study areas of Ilam province. While, except for soil’ s K (p < 0. 01), growth type had no significant effect on soil properties which indicates that climate effectiveness is more important than growth type on soil properties. The highest and lowest pH was found in Syrvan with 7. 4, and in Ilam and Eyvan with 7. 1, respectively. Ilam region with 556 mm rainfall had the most amount of OC=31% compared to Eyvan and Syrvan regions. Simple correlation for two growth types showed steady trends between variables and most soil variables had strong and significant correlation (α =0. 01). Generally, climate had more influence than growth type on soil properties which indicates the importance of climate on soil forming processes. Based on growth type characteristics, Ilam has the best conditions for oak tree growth in terms of soil and climate.

In plant ecohydrology studies, stemflow considered as point input of rainfall into plant ecosystems. To date, due to field measurement, time-consuming and the high cost of stemflow measurements, models are used to estimate the stemflow amounts. The study aimed to test the performance of three physically-based model of Gash and revised versions (Gash-1 and Gash-2) to estimate the stemflow in an elder pine (Pinus eldarica Medw. ) stand in the Chitgar Forest Park for the three-years study period. Rainfall magnitude and throughfall were measured with 10 and 60 rain-gauges, respectively. Stemflow was measured for 9 trees in each stand that were considered representative of the stand. According to the validation step, Gash and Gash-2 models were found to be the best models to estimate the stemflow, respectively, however the performance of each model was different at each rainfall magnitude class. For the very small rainfall class (lower than 2. 50 mm), estimation of all models was incorrect. For the small (2. 51-5. 00 mm) and medium (5. 01-7. 50 mm) rainfall classes, Gash-2 was the best model, while Gash model estimated very well for the large (7. 51-10 mm) and very large (more than 10. 00 mm) rainfall classes. In conclusion, Gash model requires few input variables, hence would be more applicable than to other models. Due to climate change, which is affected by the frequency of rainstorms in different rainfall magnitude classes, it is necessary to use appropriate models to estimate the amount of stemflow.

Investigating the relationship between distribution of plant species and environmental factors is one of the main issues in plant ecology. Habitat suitability or species distribution models, are defined as statistical analysis algorithms which relates species data to the environmental predictor variables. This study aims at predicting the habitat suitability of Wych elm species in Kheyroud forest using Maxent model. Wych elm is one of the most invaluable native species in Hyrcanian forest. However, due to the outbreak of Dutch elm disease in recent decades and illegal cutting of this species, its dominance has been significantly decreased. Therefore, the primary and secondary topographic attributes derived from digital elevation model with 12. 5 m resolution along with soil characteristics, soil fertility, and geology maps, were extracted at each Wych elm location. Using selective sampling and inventory data, 873 Wych elm individuals were recorded. The results showed that Maxent model has a high potential to predict the suitable habitats for Wych elm based on AUC criterion. Altitude and valley depth were the most important variables in determining the habitat suitability for Wych elm species. Moreover, 32. 57% of the study area has an acceptable potential for the presence of this species. Due to the optimal moisture, thermal, and topographic conditions in mid-lands, this area is the best habitat for this species in Kheyrod forest. The generated model can be used as a tool for the forest experts and managers to help conservation and rehabilitation of Wych elm in this forest.

Agaric fungi are a large group of Basidiomycetes that known as mushrooms in the broad sense. In order to identify and characterize the agaric fungi in oak forests of Kermanshah province, specimens were collected in 2014-2015. Microscopic and macroscopic characteristics including size and color of cap and stem, size and shape of basidia, the number of strigma, size, shape and color of spores and cystidia type were checked. Both morphological and ITS sequencing were used for identification. DNA extraction was carried out using a Genomic DNA Purification kit. The ITS1, 5. 8S, and ITS2 (ITS) Regions were amplified using ITS1 and ITS4 primers. Fragments about 600 bp were amplified and after sequencing deposited in GenBank. Based on both morphological and molecular characteristics Agrocybe praecox (KT833856), Cyclocybe cylindracea (KT833863), Coprinopsis atramentaria (KT833863), Entoloma serrulatum (KT833862), Hebeloma alpinum (KT833861), Hypholoma fasciculare (KT833860), Lactarius glaucescens (KT833859), Lepiota cristata (KT833859), Pholiota gummosa (KT833858), Psilocybe atrobrunnea (KT833864), Psilocybe cyanescens (KT833857), Stropharia aeruginosa (KT833865). Boletus erythropus and Irpex lacteus were identified in Kermanshah province. Hebeloma alpinum, Entoloma serrulatum and Cyclocybe cylindracea are new for Iran mycoflora. All representatives were deposited in fungal collection of Plant Protection Department, Razi University, Kermanshah, Iran.

Today, the important of growth models as an important management tool and factors affecting them is clear. So, in this study, factors affecting the growth models were examined. Data from 256 permanent sample plots for the years 2003 and 2012 of Kheyroud Forest was used. First, the relationship between topographic factors including slope, direction and altitude with site productivity for beech was obtained using an empirical regression model. Then, the factors affecting the individual trees diameter increment were investigated using regression relations. Also, in order to better understand the effect of these factors, tree species were separated in four species group as beech, hornbeam, chestnut-leaved oak and other species. In order to evaluate the model, three statistics including RMSE, MBE and performance coefficients were used. The results showed that the relationship between the site productivity index and three factors of direction, gradient and elevation is sinusoidal, almost decreasing, at first increased and then decreased. Also, the behavior of the studied indicators in relation to tree species is different. For instance, in the diameter increment model of beech species, all of the indices, except for site productivity and Shannon-Wiener index had a significant effect and the use of these indicators for beech species reduces the error and bias and increases the efficiency of the model. The mortality model was also presented with a high percentage prediction. In general, the present study showed that the relationship between growth models and various indices has a lot of complexity and more research is needed.

Today, skeletal musculoskeletal disorders are one of the most important occupational health issues and have a high prevalence in almost all occupations, and preventing it involves evaluating and modifying working conditions. This study aims at assessing the risk factors of musculoskeletal disorders of work by QEC in forestry workers of two regions of Guilan and Mazandaran forests. In this study, statistical population included 51 workers in three jobs of felling and bucking, skidder driver, and manual loading worker were studied by census method. The Nordic questionnaire and QEC method were used for determining the prevalence of musculoskeletal symptoms and assessing the risk of these disorders, respectively. The results showed that the highest prevalence of musculoskeletal disorders was in the waist, neck and back segments, respectively. The significant relationship between weight, body mass index, work experience and smoking with musculoskeletal disorders was observed. Results of QEC evaluation showed that the 72. 6 percent of worker are in risk level of 4, while these values for risk level 1, 2, and 3 were 7. 8, 9. 8, and 9. 8, respectively. In vibration exposure, speed of operation and stress about 64. 7, 62. 7, and 70. 6 percent of worker were in high and very high levels. The results indicate a high prevalence of disorder among workers. The main ergonomic problems in study area include inappropriate physical condition, bending and twisting of the waist, lifting and carrying heavy loads, vibration, speed during work and stress.

This research was carried out for investigating the effect of stand density on the richness and diversity of spring gallwasps species in Quercus branti stands in Sardasht forest (West Azarbaijan province). The effect of density on the diversity and richness of gallwasps was investigated in three populations with completely sparse, sparse, and relatively dense stands. A total of 30 samples with an area of 400 m2 were arranged to record the quantities of woody species and the type and frequency of gallwasps species. In each sample, the frequency and types of herbaceous species were recorded in 5 subsample (1. 5×1. 5 m). The results showed that there were eight gallwasps from the Cynipidae family in Sardasht forest. The Shannon evenness index of gallwasps was significantly correlated with the number of coppice, the mean diameter and the mean basal area. The Simpson species index of gallwasps was in correlation with the mean basal area. Furthermore, we found a significant correlation between Shannon species diversity, Shannon evenness, and Simpson species diversity of the herbaceous species and Shannon species diversity, Shannon evenness, Simpson species diversity and Margalef species richness of gallwasps.