Journal of Wood and Forest Science and Technology
Year:2018 | Volume:25 | Issue:3|Papers Count:8

Background and Objectives: Swelling soil such as clay soil is known as unsuitable material for forest transportation due to the high volume change and mechanical defects. The aim of this study was to investigate the capability of biologic stabilizers with silica content such as corncob ash for enhancing and improving the mechanical strength of soil in recommended forest roads of district two in Bahramnia forestry plan in Golestan province. Materials and Methods: The combination percentage of corncob ash and curing time were the treatments of study. At first, the waste of corncob was collected from farmlands. The nodes of stem which have higher amount of Silica were separated and then grind and heated in furnace at 580° C for 2 hours. The 50 swelling soil samples were brought from the depth of 0-20 cm in 100 meters of recommended roads to the soil mechanic laboratory using the systematic randomized sampling method (each sample with a weight of 2 kg). Samples were treated by 5, 10, 15 and 20% corncob ash and in curing times of 7, 14 and 28 days the tests of Atterberg limits, standard proctor and unconfined compressive strength were done with three replications. Results: Findings showed that the plastic index decreased by increasing corncob ash to 5% and then the use of ash more than 5% increased the plastic index. With increasing the amount of ash in the mixture, the dry bulk density of the mixture decreased and optimum moisture content increased. Maximum dry density was 1. 73 g cm-3 which was recorded in optimum moisture of 28. 5% and in corncob ash content of 5%. Unconfined compressive strength of the mixture increased until adding 5% of ash, and then the compressive strength decreased by increasing the ash content. Increasing the curing time causes that the maximum dry density and compressive strength to increase whereas the plastic index decreased. In most of the cases, there wasn’ t significant difference between the curing times of 14 and 28 days. Conclusion: Findings indicated that because of the pozzolonic properties of corncob ash, it is enough to use the optimum amount of 5% and curing time of 14 days for improving the mechanical properties of swelling clay soil of forest road bed.

Background and Aim: The mmistletoes are a significant and diverse group of nasogastric species, which are parasite and have a wide range of hosts and a very wide range of distribution areas in the world. They have high levels of effective compounds. Considering the fact that the amount and type of these compounds in plants are highly dependent on environmental and genetic factors, the present study aims at the investigation of the effect of different hosts e. g Persian ironwood (Parrotia persica), hornbeam (Carpinus betulus), alder (Alnus glutinosa) and poplar (Populus euramericana) on the mistletoe secondary metabolites (phenol, flavonoids, antioxidants, Betulin and Betulinic acid) changes. Materials and Methods: Sampling for this laboratory study was carried out in late September in mistletoe hosted by Persian ironwood, Poplar, Hornbeam and alder, this species in 3 replications in lower points to the middle of the forest of Dr. Bahramnia forestry plantation located in Shast Kalateh forest of Gorgan. Then, Samples were dried, milled and extracted with three ethanol, methanol and acetone solvents. After the extraction, the required test process was performed and the obtained data were analyzed using SAS software. Results: The results showed that different hosts had significant effects on effective compounds of mistletoe. According to the results, the highest levels of antioxidant (95. 03% free radical) and phenol (4. 45 mg/g dry weight) were related to the stem acetonic extract and leaves ethanolic extract of mistletoes hosted by Persian ironwood, respectively and the highest amount of flavonoids 2. 07 mg/g is related to the mistletoe stem ethanolic extract hosted by alder species. The highest amount of betulin (147. 3 mg/ml) was measured in the mistletoe leaf hosted by hornbeam species. The highest amount of betulonic acid was found to be 347 mg/ml, which was obtained from the mistletoe stems hosted by the poplar species. Conclusion: The results indicate that the host trees can play a key role in the amount of secondary metabolites and the antioxidant properties of leaf and stem of the mistletoe half-parasite. The presence of these secondary metabolites with medicinal and even industrial value in this plant emphasizes the need for special attention on this valuable species. Due to the fact that two effective anti-cancer agents of betulin and betulinic acid are important and highly costly drugs, the mistletoes hosted with hornbeam and poplar can be used.

Background and objectives: The presence of roads plays an important role in the occurrence and prevention of forest fires, which causes damage to the ecosystem of the soil and seriously endanger the ecosystem's performance and service, and threat the stability of forest eco-environment. The rising incidence of this event has increased the need to develop appropriate management plans for areas that are susceptible to fire. Therefore, the present study investigates the role of the transit road known as the Asian Shahrah, which passes through the Golestan National Park and has direct and indirect effects on the park fires. Materials and methods: In this study, first the human factors (distance of transit road, side roads, villages, tourist areas and the presence hunters and farmers) affecting the fire in this area was determined. After that, according to the way of influencing, these layers were fuzzy and weight factors were obtained in two cases of transit road and transit road transport using the Analytic Hierarchy Process. After determining the weight and prepare invoices using the weighted average method arranged in six scenarios and modeling was performed both with and without transit road and best-case scenario was found with comparison with the real situations fire map and use of the Relative Operating Characteristic statistics. Finally, zoning with regard to the risk of using Run macro modules, and where the zones were fitted. Results: Results showed the role of transit roads in the presence of 0. 296 weight and transfer road with 0. 077 weight. The Scenario with the average level of risk and decompensation was recognized as the best scenario with ROC = 0. 87. The results also showed that if transported, the high risk areas would from 5647 ha would reduce to 2986 ha which is in fact 47% reduction of the whole high potential risk area. Road transit plays a direct role in 46 percent of fires in the area. Conclusion: Considering the high weight of the road presence role in the fires of Golestan National Park, it can be said that Because of the presence of Turkmen Sahra region, and also deserts and plains of Semnan province in the north and south of Golestan National Park, warm winds from these areas blowing to the Golestan National Park, so there are favorable conditions for fire occurrence in the park, which will increase the chance of fire in the park by high traffic on the transit road. Therefore, with due attention to the role of the Asian highway in wildlife road accidents and the loss of countless numbers of them and probability of fire occurrence in the region, the need to transfer this road to the outside of the park is felt more and more.

Background and objectives: The phenomenon of decline and tree mortality of various oak species has been reported in vast areas of the world since the early nineteenth century. Overseas studies are often on thinning sanitary cuts and sanitary control methods of woodborer pests against decay of cut woods, and no considerable research has been done on pruning of forest trees to save infected trees from pests and diseases. Furthermore, significant researches have been reported about the positive role of pruning of various fruit trees in pest control and pathogenic agents across the Iran and in the world. In recent years, relatively comprehensive researches have been done on the dieback of Zagros forests from different aspects. Given that the chemical struggle against pests and diseases in the natural ecosystems is not recommended and the biological struggle is based on the long-term research needs, so now the application of the sanitary cuts is considered as the most important strategy to control the declining of Persian oak trees. In this regard, the purpose of this study was to investigate the role of several treatments of cuttings and pruning against the dieback of Persian oak trees in the Melahsiah forests of Ilam province. Materials and methods: To conduct this research, the effect of 10 treatments of two factors including vegetative form and cutting type were studied based on completely randomized design by the factorial method. Vegetative form was studied at two levels of high and coppice and cutting type in five levels including removal of infected parts of trees, complete removal of the crown, cutting from height 10 cm and cutting from 10 cm depth and control treatment (without sanitary cutting). Due to the lack of necessary conditions of parametric statistical assumptions (analysis of variance), the comparisons between average two forms of vegetative forms treatment were performed by Mann-Whitney non-parametric test and the comparison between group and pair average of cutting methods by Kruskal-Wallis and Tamahan non-parametric tests respectively. Results: The results showed that there was no significant difference between the survival and viability averages of two vegetative forms (high and coppice) in the 5% probability level. The results indicated that the difference between the mean of survival percentage of two treatments for removal of infected parts and removal of 100% crown was significant at 5% probability level and the average difference of the other treatments with the average of control treatment was not significant. Also, the results of comparing the average percentage of viability for the five treatments of the sanitary cutting factor showed that the difference infected removal part with control treatment was significant at 5% probability level and the difference of other treatments with control treatment was not significant. Conclusion: Based on the results, treatments including cutting at a depth of 10 cm, cutting from 10 cm tree height and removal of 100% tree crown have not been able to have a positive effect on the improvement of survival and freshness, and therefore, the implementation of these sanitary cuttings is not recommended. In general, in order to reduce the dieback damage of Persian oak trees, the implementation of sanitary cutting of selective removal of contaminated branches is recommended in similar areas with the study area.

Background and objective: During last two decades, nano-biomaterials like cellulose nanofiber (CNF) and chitin nanofiber (ChNF) have attracted the attention of many researchers to make different products. The most important properties of these nanomaterials are bio-compatibility, bio-degradability, renewability, owning cheap available raw materials, owning high mechanical properties and safety. Based on these promising properties, a wide variety of applications has been created for these nanomaterials. One of these products is transparent and tough nanopaper in which hydrogen bounds are created among nanofibers with no adhesive or additives. In recent years, many researchers have been focused on the production, optimization of properties and utilization of CNF and ChNF nanopapers in different applications. Based on the technical and functional properties of CNF and ChNF and nanopapers, as well as the necessity of doing more investigation and evaluation on these nano-materials and nano-products for the future researches and applications, it was aimed to compare the properties of CNF and ChNF nanopapers in this study. Materials and methods: To do this research, CNF and ChNF gels were prepared from Nano Novin Polymer Co. (Iran). To make nanopapers, the gels were first converted to mat using vacuum filtration process and then the mats dried in a vacuum oven at 70 ° C for 24h. The fabricated CNF and ChNF nanopapers were characterized using atomic force microscope (AFM), qualitative transparency, X-ray diffraction (XRD), tensile, and air permeability tests. Results: The results showed that the average diameter of CNF and ChNF was 35 and 26 nm, respectively. The nanopapers prepared from both CNF and ChNF showed complete barrier properties against air. The XRD curves of CNF and ChNF nanopapers were completely different. The crystallinity index of CNF and ChNF nanopapers obtained were 68% and 90%, respectively. The tensile strength, Young’ s modulus and strain of ChNF nanopaper were higher than those of CNF nanopaper. Conclusions: CNF and ChNF are both nanomaterials simultaneously owning the most important technical, economic and environmental properties. Also, the nanopapers made from these nanofibers showed promising physical and mechanical properties including complete barrier properties to air, high transparency, and mechanical properties; hence, based on these promising properties and ongoing intensive researches on this product, CNF and ChNF expect to be used in a wide variety of applications including medicine, papermaking, electronic, magnetic, food packaging, etc.

Background and objectives: Many additives are usually used in wet end papermaking in different sections for specific goals. When using several additives, the sequence of adding materials often influences differently on final paper properties. In this research, the sequence of adding cellulose nanofibers, cationic starch and polyacrylamide to pulp and their impact on drainage time, handsheet density and tensile strength were investigated. Materials and methods: In this research, bagasse bleached pulp from Pars paper mill, supper grinded cellulose nanofibers, cationic starch with 0. 035 mol/mol substitution degree, and high molecular weight and low electrical charge cationic polyacrylamide were used. Prior to make papers, 3% cellulose nanofibers (with 0. 3 % concentration), 1% cationic starch (with 0. 5 % concentration), and 0. 3% cationic polyacrylamide (with 0. 05 % concentration) were added in different orders to bagasse pulp to make handsheets. Results: The results showed that adding materials in every sequence increased density, tensile strength, and drainage. The best sequence of two adding materials was for adding cationic polymer firstly and cellulose nanofibers secondly to dilute pulp suspension through which it is assumed that fibers and cationic polymers make large agglomerates which break to smaller fractions afterwards with shear force. In the following, adding cellulose nanofibers and being absorbed to cellulose fiber networks resulted in paper higher tensile strength and a limited increase in drainage. Between the sequences of adding three materials, tensile index and density of papers showed no significant differences. Nevertheless, adding three materials in every sequence increased tensile strength significantly compared with two materials and control specimen. In addition, when cationic starch is added firstly the least drainage time and when cellulose nanofibers added firstly the highest drainage time were observed. Furthermore, in specimen with three adding materials, the highest thickness was measured when cellulose nanofibers had been added firstly. Conclusion: Using cellulose nanofibers together with cationic starch and polyacrylamide, while implementing shear forces, retains micro and nano fines and can increase paper density and pulp drainage time. To sum up the influences of additive sequences on tensile, density and drainage, it can be concluded that the sequence of adding two materials of cationic starch at first and cellulose nanofibers at second, and the sequence of adding three materials in the order of cationic starch, polyacrylamide, and cellulose nanofibers respectively were introduced as the best orders for papermaking from bagasse pulp to be able to gain the highest tensile strength and the least drainage time.

Background and objectives: Acoustic property as one of the special characteristics of wood is widely used in making musical instruments. Finding information about the acoustic properties of wood and all factors which improve it is so important. Furthermore, modifying the characteristics of wood with environmentally friendly methods has become increasingly important recently. In the current study, two wood species native to the north of Iran that is Beech (Fagus orientalis L. ) and Maple (Acer velutinum) were examined in terms of their acoustic properties. Samples were also treated under hydrothermal treatment. The effects of hydrothermal treatment on acoustic properties of the samples were measured by free-free flexural vibration method. Materials and methods: In order to examine the acoustic properties of two wood species of Beech and Maple, samples in the dimensions of 360 (longitudinal) × 20 (radial) × 20 (tangential) mm were cut according to ISO 3129 standard. Hydrothermal treatment at 150 ° C for 5 hours was applied on samples. Acoustic properties of the treated samples such as modulus of elasticity, damping of vibration, wave velocity, quality of sound, acoustic coefficient and acoustic conversion efficiency were evaluated in two directions of Longitudinal-Radial and Longitudinal-Tangential. Acoustic properties were compared with control samples. Results: The results of this study showed that hydrothermal treatment of wood has a significant effect on improving the evaluated acoustic properties except for the modulus of elasticity and acoustic coefficient factor in comparison with control samples. In general, the greatest effect was observed on mortality hydrothermal treatment of wood, the quality of sound, and acoustic conversion efficiency in species of Maple. The results also indicated that there was no significant difference between the acoustic properties in two directions of Longitudinal-Radial and Longitudinal-Tangential in the treated samples. Conclusion: The effect of hydrothermal treatment on improving acoustic properties of the samples could be due to the withdrawal of water soluble extractives in samples with cleaning material accumulated in vessel ducts, fiber and other structural elements of wood, as well as increased dimensional stability during treatment in treated samples. According to the results of this study, the hydrothermal treatment of wood species, especially Maple species can be used in manufacturing sound-boards as well as resonator boxes of musical instruments such as Xylophones, Violin, and the Iranian Santour.

Background and aims: The aim of this research is the possibility of using the waste of the laminated paper lines of melamine considering as an alternative to the adhesive to make three-layer particleboard at the laboratory level. Method and materials: In this study, the amount of replacements of the laminated paper waste on the core layer relative to the urea formaldehyde adhesive in 4 levels 0, 20, 40, 60 percent dry gum weight was used to save and reduce adhesive consumption which was performed at the laboratory level with 5 replications. Mechanical and physical resistivity of produced boards as including flexural strength, modulus of elasticity, internal adhesion, screw resistance, density, thickness swelling and water absorption after 2 and 24 hours immersion in water were measured according to EN standards. Results: The results show that increasing of the laminates paper waste, bending strength, elastic modulus, density the strength of the screw on the surface and the cores of the board and the internal adhesion of the board are reduced to the control sample. However, all the particleboards produced from laminates paper waste up to 40%, higher than the Iranian national standard (9044) requirement. Furthermore, by increasing the lining coating powder, increased the percentage of thickness swelling and water absorption in 2 and 24 hours and density. Conclusions: Physical and mechanical properties of particleboard up to 40% of coated waste more than Iranian national standard (9044). Therefore, even with the addition of 40% of the powdered lining on the core layer, these boards are suitable for indoor furniture for use in dry conditions with synthetic sheathed capability. So by replacing the melamine coating with the glue of formaldehyde in the core layer, while reducing the adhesive consumption and releasing formaldehyde, it can be produced panels with a resistance to the standard of Iran.