فصلنامه جنگل و فرآورده های چوب
سال شصت و ششم شماره 4 (زمستان 1392)

The potential environmental toxicity of argent nanoparticles (AgNP) was evaluated on germination characteristics of Pinus silvystris seeds. Seeds were exposed to different concentration of argent nanoparticles in soil and aqueous suspension (0, 10, 20, 40, 80 and 100 mg/kg soil and 0, 10, 20 mg/L water). The seed germination percentage, the speed of seed germination and cell membrane stability were calculated. The inhibitory effects of argent nanoparticles were observed for seed germination percentage, the speed of seed germination and cell membrane stability at 80 mg/kg soil. Conversely, the inhibitory effects were observed for seed germination characteristics in aqueous suspension at very low concentrations (at 10 mg AgNP /L water). The obtained different results in soil and aqueous suspension could be due to absorption and aggregation of argent nanoparticles in the soil, which can modify their mobility, bioavailability and possibly their ecotoxicity. According to the results, further researches are needed to identify the ecotoxicolgical effects of argent nanoparticles using abundantly for industrial and common use.

Nowadays, natural ecosystems degradation and its conversion to other land uses can create considerable changes in soil properties. The present study was conducted to investigate impact of land use change on soil physical, chemical and biological properties in five common types of land-uses in the mountain forest area in the north of Iran (in a part of Alandan district, Mazandaran– Sari), namely arable land, pine plantation, ash plantation, beech stand and destructed forest stand. The soil samples were taken from soil depths 0-10, 10-20, 20-30 cm with using coring method (8 cm diameter) in each site randomly (n=6). The moisture content of soil, pH, EC, bulk density, available K and Ca, organic carbon and total N, NH4 + and NO3 - concentration was measured in the laboratory and Net N mineralization, net ammonification and net nitrification was calculated. Results showed significant difference (P<0.05) in soil physical and chemical properties between different land-uses types. As, the higher pH, available Ca, total nitrogen and ammonium were observed in ash plantation and lowest total nitrogen, pH amount and litter decomposition rate (highest C/N ratio) was found in pine plantation. Also, net N mineralization and ammonification were occurred just in the soil of Ash plantation. Results of this study indicate a significant impact of different land use type on soil properties.

Roads provide access to forest resources for properly management of timber production, transportation, forest protection and ecotourism. Forest road networks are usually the main source of sediment in forest watersheds. Globally, soil erosion is one of the most important environmental problems which is threaten soil and water resources. Therefore, poor planning and construction causes pollution of forest streams and damage to aquatic life. Road Gradient is one of the main factors of road construction standards. Determining the relation between road gradient and amount of sediment production can be used efficiency by forest manager to choose proper gradient for new roads. This study was conducted in Kohmiyan Forest-Gorgan, and three different segments with 3% 6%, 6%-9% and 9%-12% gradient were selected on road network. investigation Using rainfall simulation the effect of road gradient on amount runoff production and sediment was assessed. In three segments, other parameter such as: roadbed, amount traffic and precipitation are similar. The results indicated that the average amount of runoff produced in segment 1 (gradient 3%- 6%), segment 2 (6%- 9%) and segment 3 (9%-12%) were 21.00, 35.60 and 51.10 litter respectively for each one square meter and average amount of sediment were 3.54, 8.11 and 12.11 g/l. The results of analysis of variance showed significant differences between amount of runoff and sediment due to road gradient. The results of Tukey test showed significant differences among mean runoff and sediment of three segments and increasing with increased road gradient. So keeping the road gradient in standard range is an important factor for controlling runoff and sediment.

There are natural and human threatening factors of forests sustainability. Deforestation human factors include grazing, fire, land-use, mining operation, wood smuggling and release of waste in the forest. There are very high harmful effects of livestock grazing in forest. In this study effects of livestock grazing were investigated on occurrence, diversity and changes in natural regeneration groups. These regions in this study consist of Bonjehbon and Patom corral were located in Patom district in the Kheyroud Educational and Experimental Forest which belonged to University of Tehran. For this purpose samples were collected by moving from each corral in four routes as transect until custom unit boundary. There were determined 2×2.5 (5 m2) plots in each regeneration group and was determined woody and herbage species in those plots. Diversity and evenness indices were calculated by using Ecological Methodology software at 500 m distances from corral. The results show that the most seedlings are Carpinus betulus and Acer velotinum which forms main species in this region. Graph change species showed reducing trend of the frequency of C.betulus and A.velotinum species while increased abundance of F.orientalis by increasing distance from corral. Rising pattern was observed in the diversity and evenness factors by increasing distance from corral. Dominant herbage species include Oxalis acetosella, Rubus fruticosus, Sambucus nigra, Euphorbia amygdaloides, Pteridium aquilinum, Oplismenus unulatifolios and dominant woody species include D.lotus, C.betulus, Crataegus Spp, Mespilus germanica, Acer cappadocicum, Parrotia persica and Prunus divaricata at closer distances to corral. High diversity of woody and herbage species showed severe degradation at the regions near the corral which has led to appearance invasive species.

Crown cover is one of the most important biometric characteristics applied in Zagros forests management that its measurement is more important in coppice trees because of their asymmetric crown shape. The aim of this research was investigating on the accuracy and precision of different mensuration methods of crown area measurement in Persian Oak coppice trees and the possibility of mean crown diameter estimation of these trees by UltraCam-D imagery. The maximum and minimum crown diameters of 125 Persian Oak coppice trees were inventoried in a 30 ha plot in the forests of Kohgiluye-BoyerAhmad province. The crown area of each tree was measured on UltraCam-D aerial imagery of the study area. Two circular and elliptical shapes and two mathematical and geometric methods of calculating mean crown diameter were analyzed in this respect. The results showed that the applied methods have no significant difference with the true crown area and they were accurate enough. Although the crown area of the trees with circular shape and mathematical mean diameter were 8.9 percent and with circular shape and geometric mean diameter and elliptical shape were 7.7 percent greater than the true values. The elliptical shape was also more precise in measuring the crown area than two other methods. It was also possible to estimate the mean crown diameter of Persian Oak coppice trees applying the aerial imagery and cubic models with no significant difference from the true values.

This study was conducted to investigate the effect of provenance of Persian oak species on its acorn morphological traits and growth and survival parameters in different latitudes of Zagros region. Mother trees of three sites from northern (Baneh), central (Khoram-Abad) and southern (Yasuj) Zagros region were selected and their acorns planted as a completely randomized design in common garden in Yasuj. Acorn morphological traits and growth parameters of seedlings like height, collar diameter, number of leaves and volume in June and September and survival of seedlings were measured. Analyse of variance showed that all acorn morphological traits except acorn diameter at first one of 0.1 height and number of acorn per kg had difference significant. High latitudes provenance had highest value of width, navel diameter and acorn volume and lowest value of length, length to width ratio. Growth and survival traits of seedlings from three provenances were significantly different so that seedlings originated from Baneh were showed highest value growth and survival traits. Results of correlation showed that width, navel diameter and acorn volume were positively and length, length to width ratio and number of acorn per kg were negatively correlated with latitude and growth traits of seedlings. The highest amount of vitality was belongs to seedlings of southern Zagros. Results of cluster analysis also showed that seedlings germinated from mother trees of Baneh and wide navel diameter of acorn had better primary establishment in Yasuj.

Plantations can effect on understory plants by changing in soil components or by shade effects of canopy cover positively or negatively. This study aimed to investigate effects of reforestation by exotic fast growing trees on understory plants diversity. Three plantation stands, Turkish red pine stand, black locust stand, and mixed stand of Turkish red pine and black locust, and a natural Iranian Oak stand were sampled. In order to measure plants diversity, sampling was performed in the same physiographic landform, using 400 m2 main plots composed of 5, 4 m2 subplots in center and corners of main plot. Soils were sampled in three 0-10, 10-20, and 20-30 cm horizons. Results showed that species richness in Turkish red pine, black locust stand, and mixed stand of Turkish red pine and black locust, and Iranian Oak stand were 16 – 30 – 31- and 34 respectively. Sorenson and Jaccard similarity indices showed the most similarity between black locust stand, and mixed stand of Turkish red pine and black locust, and least similarity between Iranian Oak stand and Turkish red pine stand. Maximum and minimum value of Simpson dominance index was seen in Turkish red pine stand and Iranian Oak stand respectively. Iranian Oak stand with six species had the most endemic ground flora species and Turkish red pine with one species had the least. Respect to trivial changes in soil properties, in addition to soil changes effects, changes in species diversity may relate to heavy canopy cover and shade effects of it.

Intense competition in the markets Require Small and medium industries to achieve competitive advantage, with the aim of obtaining greater share of the market. In the past, activities performed such as supply and demand planning, preparation, production and distribution, at the company level has shifted into the supply chain level now. Furniture industry has high potential from the viewpoints of income, employment and value added. The present study evaluated the furniture industry supply chain in Yaftabad, Tehran that it is one of the major centers of this industry. In this Research, First, a field study was conducted; the distribution map for units related to the furniture industry was prepared using ARCGIS software then in next step data gather using questionnaires and were analyzed using cluster analysis method. The results showed the supply chains of this industry are concentrated in the area around East 17th Avenue, Yaftabad. And despite the apparent concentration observed, real association is among the local furniture industry supply chain Yaftabad District 18, also it was appeared that, although workshops are closer to the raw materials suppliers in District 18. But the economic growth is higher in workshops located in district 17. So, it was concluded that for economic growth it is not enough to be close to the supply of raw material. But other factors such as risk, innovation, Exports, interest group and competition must be considered.

board density by regression models, this study was carried out. Regarding two variables: wood dry density (460, 630 and 790 Kg/m3) and board density (520, 620 and 720 Kg/m3) one layer particleboards were made. Board properties such as MOR, MOE, shear strength, water absorption and thickness swelling (after 24h immersion) were measured. Stepwise multivariate regression models were used to evaluate the effect of the above variables on board properties and to determine the most effective parameter. Equations indicated that both two factors affected the models of MOR, shear strength, WA and TS based on the degree of their importance. The effect of the variables on MOE was not significant. Results from minitab contour plots revealed that increase in board density caused to improvement mechanical properties. Regarding the shortage of initial wood resources, it is possible to making particleboards with density of 520 - 620 kg/m3 with mechanical properties within those required by corresponding EN standard. TS values were higher than requirements. Panels required additional treatments such as using amount of water resistant materials.

Foreign trade has a significant role in economic development that some of experts know it as an engine or fuel for economic growth and other know it as growth car oil and some consider it as international inequalities exacerbated factors. In the classical theory of international trade, exportcharacteristic foreign trade. Given the limitations and barriers that exist for oil exports, the countries are seeking to non-oil exports that one of these products are Wood and Furniture industry. And nearly 2 percent share of considering in world trade this industry, and also the history and potential of this industry in Iran, Development of this industry and provide meaningful presence in international markets can impact on growth GDP and was earn non-oil income for the country. The aim of this study is determination of the effective Indexes on development of export Iran furniture industry using Group Decision Making method. For this purpose, after preliminary investigation, preparatory observation, and an interview with some of the furniture producers and relevant experts, effective criteria were divided into six major groups and as well as 48 sub-criteria. Since getting expert's opinions via questionnaire, the priority rates of obtained criteria and sub-criteria were determined by Analytical Hierarchy Process (AHP). The results show that Raw materials & product and market & economy criteria have the highest weighting values at the first level. In addition among 48 effective sub-criteria, sustainable supply of raw materials, development of strategic marketing, improving financing systems and low interest, participation in international exhibitions, quality control, durable raw materials and capable banking system have highest priorities weighting values, respectively. considering government policies and decisions in the fields of raw materials wooden, currency and banking, and marketing infrastructures, Complete accompany government with the furniture industry, to maintain the be generated and competitiveness of furniture industry Iran first step, And access to potential export markets presence the second step, a necessary condition is considered for the presence of this industry in world markets.

The effect of partial pre-extraction of hemicelluloses on the properties of rice straw soda AQ pulp to produce valuable by products from this pre-extraction was investigated. The pre-extraction conditions were conducted using 10% sodium hydroxide (based on dry weight of the rice straw), at 50 °C for 90 minutes to reach the extraction rate of 48.1% of the hemicelluloses. Soda-AQ pulping was performed under different conditions at pre-determined pulping time and liquor to straw ratios. The optimum pulping conditions was found as 14% active alkali, 160 °C and 45 minutes pulping time. Comparasion of per-extracted materials with the normal rice straw indicated that to achieve the same kappa number and yield, the pretreated material requires less alkali and cooking time. The results showed that pre-extraction marginally reduced the tensile strength index of the pulp which the difference was not statistically significant with control pulping condition. However, the burst strength index of pre-extracted pulp and control was identical. The overall mechanical properties of pretreated pulp were the same as the control.

In the present study, chemical-physical properties of nanofibers isolated from whole kenaf stem and kenaf bast fibers were characterized by Transmission Electron Microscope (TEM), Fourier Transform Infrared (FTIR), Thermogravimetric Analysis (TGA), and X-ray Diffraction (XRD) analysis. The isolation was done using chemo-mechanical processing where the chemical methods were based on NaOH-AQ (anthraquinone) and three-stage bleaching (DEpD) processes. The mechanical techniques involved refining, cryo-crushing and high-pressure homogenization. Microscopy study showed that the diameter range of isolated nanofibers from kenaf stem was finer than kenaf bast nanofibers, while their length was similar and in the micrometer range. Fourier transform infrared spectroscopy (FTIR) study demonstrated that the functional groups for both nanofibers were almost the same and no significant differences were observed. The results from thermo-gravimetric analysis showed a better thermal stability for kenaf bast nanofibers compared to the kenaf stem nanofibers. X-ray analysis revealed that the crystallinity of the studied nanofibers was increased after the chemo mechanical isolation process. In addition, the crystallinity was 81% and 63% for kenaf bast and kenaf stem nanofibers, respectively.

Nano and micro particle systems including a cationic polymer such as cationic starch and nanoparticle such as bentonite have been utilized as retention and drainage aid. In this research, the effect of simultaneous addition of cationic starch and bentonite nanoparticles on fine retention, and drainage of the pulp slurry and on some strength properties of hand sheets were investigated. A combination of the three levels (0.5, 1 and 1.5%) of cationic starch and one of the three levels (0, 0.2 and 0.4%) of bentonite were used. The results revealed that the highest fine retention was at 0.5% cationic starch addition, but the highest drainage was obtained adding 0.4% bentonite and 1.5% cationic starch. However, the interactive effect of the variables retention and drainage was not statistically significant. Application of 0.2% bentonite and 1% cationic starch; 0.2% bentonite and 1% cationic starch or 1.5% cationic starch produced the highest tensile strength index and tear strength index in hand sheets respectively. The highest burst strength index of the papers was related to the addition of only 1% cationic starch.