Journal of Wood and Forest Science and Technology
Year:2020 | Volume:27 | Issue:1|Papers Count:8

Background and Objectives: Estimating the biomass and carbon content of trees and the other vegetation is important, in particular in context of global warming and climate change and the determination of biomass is essential in order to influence the climate and management of natural resources. In forest areas with high altitudinal gradients, values of the quantitative characteristics of forest stands usually change. The purpose of this study was to determine the effect of altitudinal gradient on quantitative forest characteristics including number of trees per hectare, basal area, standing volume, biomass and carbon storage in District 3 of Sangdeh Forests. Materials and Methods: The area was initially divided into three altitudinal levels, with a range of 1400-1600, 1600-1800 and 1800-2000 m a. s. l. 50 circular sample plots were randomly assigned to each level, resulting in a total sampled area of 10 ares (0. 1ha) to cover each level. In each plot, species type, height and diameter at breast height were recorded for all trees with DBH > 7. 5 cm. Then, the density of all species was determined by sampling followed by further analysis in laboratory. Then, the biomass was calculated in the sample plots based on the FAO global model and the amount of above-ground carbon storage calculated using coefficient. Results: The results showed that from the lowest altitude to the highest the number of trees per ha is 477, 384 and 372 and the basal area is 25. 58, 29. 49 and 30. 84 m2, respectively. Also, the volume per ha were estimated to be 314. 25, 393. 98 and 424. 75 silve, respectively. The results of this research showed the amount of biomass for all three altitudinal levels based on gradient increase is 406. 68, 478. 26 and 522. 30 t ha-1 and carbon stock is 203. 34, 239. 12 and 261. 15 ton per hectare, respectively, that shows an upward trend as the a. s. l. increases. The analysis of variance indicated a significant difference between the altitude and the characteristics (P<0. 05). In addition, Spearman correlation showed that there was a significant correlation between altitude and tree characteristics including basal area, standing volume and above-ground biomass (AGB) per ha (P<0. 01). Conclusion: Conclusively, the results of this research in the study area show that changes in altitude from the sea level have caused changes in some of the quantitative characteristics of forest stands and thus the elevation gradient has been effective on the distribution of AGB, so that with increasing a. s. l, the amount of AGB has also increased and AGB has the highest correlation with the altitude from the sea level.

Background and Objectives: Dust is occurred when a vehicle passes on the dry surface of earthy roads. Dust particles can negatively affect plant growth, water quality and road life. In this study the effects of some environmental friendly anti-dust agents including different dosage of sugarcane molasses, polyacrylamide and bentonite were investigated on road dust control. Research was done in 3, 9, 27 and 81-day time frame. Materials and Methods: In each of Loveh, Kouhmian and Shastkalateh forest in Golestan province, a main road with a length of 960 m was divided into 320-meter segments for implementation of sugar cane molasses, polyacrylamide and bentonite treatments. Each concentration of treatments was conducted on 60 m. Rear-mounted solution spray system equipped with 8 nozzles was used for implementation of treatments in rate of 2-2. 5 liter per l m2. Besides, dust sucker instrument was applied to collect dust particles. Data was collected when a vehicle passed with speed of 40 km h-1. Moreover, soil samples were collected from the margin of forest roads to measure the changes in soil Na, K, Ca, Mg and pH due to leaching. Data were analyzed using factorial experiments. Results: Results showed that dust of forest roads decrease with increasing in concentration of the anti-dust agent and increased over time. In Loveh forest roads, polyacrylamide with concentration of 6% and sugarcane molasses with concentration of 20% were the most appropriate treatments. Bentonite was unsuitable due to the high amount of fines in surfacing materials. In Kouhmian forest roads, polyacrylamide with concentration of 4% and sugarcane molasses with concentration of 20% and in Shastkalateh forest roads, polyacrylamide with concentration of 2% were the most appropriate treatments. Bentonite increased the Mg and pH and Molasses increased the K and decreased the pH of soil at margin of forest roads. In other cases, there wasn’ t a significant effect from the treatments on chemical properties of soil at margin of road. Conclusion: Based on the findings, sugarcane molasses was most efficient in roads with high fine particles, but in roads with low fine particles polyacrylamide was most efficient. These additive materials have no significant effects on adjacent soil chemicals due to their low amount. It is recommended that in future studies, longevity of different concentrations of anti-dust agents and their effects on runoff quality in roads of arid and semi-arid climates to be investigated.

Background and Objectives: Knowledge of forest inventory and estimation the exact volume of trees is one of the important features in planning for forest resources. The form factor is one of the most important factors in determining the exact volume of trees. To estimate the actual volume of trees, the form factor must be calculated. The aim of this study, determination of form factor for three species (Pinus brutia, Pinus pinea and Cupressus sempervirens) in the Arabdagh reforests, And comparison of the real form factor with the natural, artificial and hohnadl factors. Materials and Methods: In this research four types of form factors including real, natural, artificial, and hohnadl factors for three species (Pinus brutia, Pinus pinea and Cupressus sempervirens) were evaluated in the Arabdagh reforests, Golestan province. For this purpose, 39 trees (13 trees for each species) randomly selected in different diameter at breast height classes from 7. 5 to 42. 5 cm (2 trees of each diameter class). In each tree, height, diameter at breast height (D. B. H) and diameter at 0. 1, 0. 3, 0. 5, 0. 7 and 0. 9 of tree height were measured, then 2 meter length logs from every tree was cutted and separated and their diameter were measured at two tops of 2 m length logs. In addition, the height and diameter of the clog and the length of the tree was also measured. To calculate the exact volume of the trunk from, the sum of 2 m long logs volumes and log were computed using the Smalian formula. Then the form factors (real, natural, artificial and Hohnadl) were calculated for each 3 species. Results: The results showed that true, natural, artificial, and Hohnadl form factor value were 0. 49, 0. 49, 0. 41 and 0. 45 (Pinus brutia) respectively. In addition, there was significant statistical difference between artificial with true form factor (α =0. 05), but There were no significant difference between natural and hohnadl form factor with true form factor. The form factors (Pinus pinea) using real, natural, artificial and hohnadl formulas was obtained 0. 51, 0. 47, 0. 41 and 0. 45 respectively. There was a significant difference between the real form factor with artificial and hohnadl form factors. However, there was no significant difference between natural form factor with real form factor. The form factors of Cupressus sempervirens using real, natural, artificial and Hohnadl formulas were obtained 0. 55, 0. 53, 0. 48 and 0. 48 respectively. There was a significant difference between the hohnadl and real form factor. However, there was no significant difference between the real, natural and artificial form factors. Conclusion: According to the results of this research, we can conclude that the natural form factor can be used as an appropriate form factor for Pinus brutia, Pinus pinea and Cupressus sempervirens, and hohnadl form factor for Pinus brutia and artificial form factor for Cupressus sempervirens can ability replace the real form factor.

Background and Objectives: Assessment and evaluation of soil seed resources in an ecosystem provide valuable information about the status of plant composition in that ecosystem. The information obtained from these studies will lead to better understanding and recognition of vegetation cover conditions in that area. In this study, for the first time soil seed potential in the Baghe-Shadi protected area in Yazd province was studied. Materials and Methods: At first, two grazing and exclosure areas were selected in the Baghe-Shadi forest site of Yazd province with similar type. Then, in each area 20 circular plots were measured in a radius of 12 meters. Samples were taken from the soil seed bank, up to 10 cm soil depth in two depths (0-5 and 5-10 cm) under the canopy and also outside the canopy in two growing seasons (spring and autumn). Density, composition and species richness of soil seed bank samples were estimated by combined method (extraction of large seeds and germination of small seeds). Results: Soil depth showed significant effects on soil seed bank. The effects of spring and autumn growing seasons were different on soil seed bank and autumn season showed a higher rate than the spring in terms of number, density and numerical values of biodiversity indices. Also, according to the results, the number and density of seed bank under crown cover was higher than outside and the exclosure had no significant effect on soil seed bank. The results of independent t-test showed that there is no significant difference between grazing and exclosure areas, but grazing area had higher seed numbers than the exclosure area. The results of analysis of variance showed that growing season and crown cover had significant effects on all studied parameters of the soil seed bank. Also comparison of numerical biodiversity indices of soil seed bank between grazing and exclosure areas showed that species richness, Simpson, Shannon-Wiener and Pielou evenness were significantly higher in autumn season than spring and below the crown cover than the outside. Conclusion: The area under grazing produces enough seed of different species, but the seedlings are likely destroyed by livestock after emergence. In fact, due to seed density and diversity of soil seed bank it can be concluded that in this forests exclosure alone can guarantee forest regeneration. But, it seems that measures must be taken to fix the problems of Amygdalus scoparia droughts and pests, especially timber beetles.

Background and Objectives: Nowadays, demand for the use of wood-plastic composites in outdoors is growing. However, wood deterioration agents such as weathering that lead to the color changes and the surface hydrophilicity increase the limitations of these products usage in outdoors. Therefore, these products need to be protected in outdoors. Different chemicals have been used to improve weathering resistance of wood-plastic composites. Nano-copper oxide has the potential to be used in the protection of wood plastic composites against weathering because of its thermal stability at the temperatures used for manufacturing wood-plastic composites and because of improving weathering resistance of wood. Hence, in this research the effect of nano-copper oxide treatment on the weathering resistance of polypropylene-pistachio twig flour composite was investigated. Materials and Methods: For this purpose, polypropylene-pistachio twig flour composites treated with nano-copper oxide at four levels (namely 0, 1, 2 and 3 percent by weight) were cut to specimens with the dimensions of 50×50×10 mm. The color characteristics and the droplet contact angel of the specimens were measured according to ASTM D 2244 and ASTM D 5946 respectively, before and after exposure to a natural weathering for 180 days in Shastklateh experimental forest located in the north of Iran. The contact angle up to 10 s after droplet application for the treated and untreated samples was measured using a contact angle analyzer PG-X. The color measurements were carried out using color guide 45/0. The data was analyzed using one-way analysis of variance and Tukey’ s test. Results: The statistical analysis of the color change data after 180 days of exposure to natural weathering showed that nano-copper oxide improved the weathering resistance of polypropylene-pistachio twig flour composite. The color stability of polypropylene-pistachio twig flour composite during weathering was improved with increasing nano-copper oxide loading. The results of the contact angel test also showed that nano-copper oxide treatment resulted in a reduction in the contact angel change due to weathering. Conclusion: The results of this study showed that treatment with nano-copper oxide resulted in improving the performance of polypropylene-pistachio twig flour composite after exposure to 180 days of natural weathering. With increasing the loading of nano-copper oxide, both the photo stability and the hydrophobicity were improved. The improvement in the weathering resistance of polypropylene-pistachio twig flour composites was attributed to the protection of lignin or other compounds of the composite by treatment with nano-copper oxide.

Background and Objectives: Today, due to environmental and economic reasons, the preparation of biomechanical pulps has expanded. In this study, hornbeam wood chips were exposed to two kinds of white rotting fungi, Pleurotus eryngii and Irpex lacteus from the forests of northern Iran for three weeks. They were cultivated according to the relevant standards. After three weeks, the chips were washed with cold water to remove fungal residues and after that, the chips air dried. Then, the chips were cooked with CMP process (temperature 170 ◦ C, L/W ratio 5: 1 and 90 minutes). 60 g/m2 hand sheets were prepared from produced CMP pulps and the optical and strength properties of pulp were investigated. Materials and Methods: The sawn boards from the height equal to the chest of hornbeam stems were air dried under the shadow for 2 months. After qualitative evaluation of boards with dimensions of 3×30×150 (thickness × width × length) cm in terms of the absence of cracks and fungal defects as well as reaction woods, from sapwood of boards, samples with dimensions 2×2×0. 7 cm were cut for normal durability test. The prepared samples were transferred to the culture medium and exposed to the destruction of the mentioned fungi for 3 weeks so that the relevant tests could be performed after the end of the destruction period. Results: On the based on the results, it became clear that the Irpex lacteus fungus in the period of destruction has acted like the white rot fungus, Pleurotus eryngii. It can be said that both fungi have the same destructive power and they destroyed the sapwood of the hornbeam about the same intensity. The average weight loss percentage of hornbeam sapwoods was 4. 13% due to the destruction of Irpex lacteus and 3. 95% by Pleurotus eryngii. The results of variance analysis of the tensile index of paper prepared from the hornbeam sapwood after 3 weeks of exposure to decaying white fungi showed that the rate of increase in tensile index by Irpex lacteus is about 9. 6% more than Pleurotus eryngii. Also, the average percentage reduction in the tear index in paper prepared from the hornbeam sapwood due to the destruction of Irpex lacteus was 14. 2% lower than that of Pleurotus eryngii. The average percentage increase in the burst index of samples in paper prepared from the hornbeam sapwood due to the destruction of Irpex lacteus was 5. 74 more than that of Pleurotus eryngii. Considering the results related to the optical properties of the papers, it can be concluded that the opacity of paper obtained from the wood chips treated with Irpex lacteus decreased compared to Pleurotus eryngii, as well as the brightness of the paper from the wood chips treated with Irpex lacteus compared to Pleurotus eryngii has been further declined. The denser texture of the paper from the treated wood chips reduces the reflection of light inside the paper fiber network, which in turn reduces the opacity. Conclusion: The optical and strength properties of the pulps have been investigated. Evaluations on the papers showed that the strength properties of the produced papers were higher after the pretreatment of the hornbeam chips with the Irpex lacteus over 3 weeks compared to that of pretretead with the Pleurotus eryngii. Considering the optical properties of papers, it can be concluded that the opacity reduced because of the more compact texture of the paper obtained from the treated wood chips and therefore the reduction of the light reflection inside the paper fiber network. The reason for the decrease in brightness in fungal treatments is the formation of chromophore groups during the incubation and pulping period.

Background and Objectives: The development of industrial clusters is one of the strategies for economic development. With the development of forest product processing clusters, savings from aggregation and production scale reduce forest production costs and increase sales and export capacity. One of the potential areas for the development of the cluster processing of non-timber forest products in Iran is the Orumanat region of Kermanshah, which, due to distribution of wild pistachio trees (Pistacia atlantica), is the source of galipot production. It is difficult to utilize and use this natural galipot, and the lack of suitable processing industries caused most of the galipot sap to be exported to other countries in unprocessed form. Therefore, it is necessary to develop a strategy for development of the processing of this valuable product in the country. The objectives of this study were to investigate the current conditions of the galipot processing industry in the Orumanat region of Kermanshah and to present a suitable strategy for cluster development of the galipot processing industry in this region. Materials and Methods: In this research, by studying the current situation, a SWOC analysis was first performed and industrial cluster development strategies prioritized using analytic network process (ANP) method. In this research, purposive sampling method was used and questionnaires were completed with the help of Delphi approach. The panel of experts consisted of 35 people. In the ANP method, the relative weight was first obtained by pairwise comparison and from the combination of these relative weights the final weights were determined. In order to perform pairwise comparisons, a 9-point preference scale was used. In order to analyze the judgments, the Super decisions software was used and for the preparation of questionnaires related to the weighting of criteria and alternatives, the Super decision-Q software was used. Finally, the questionnaire was fully answered by 29 members of the decision panel. Results: The results of the prioritization of the criteria indicated that in the strengths “ Medicinal properties” , in the weaknesses “ lack of knowledge about domestic and foreign markets” , in the opportunities “ possibility of the development of processing technology” and in the challenges “ drought and forest ecological decline” was more important. The results of prioritization of the strategies showed that “ optimization of the value chain of products by marketing reinforcement” with the weight of 0. 206 in the first priority and “ planning for the development of products with export capability” with the weight of 0. 188 in the second priority were recognized as the most important strategies. Conclusion: Considering the many medicinal properties and the possibility of developing the value chain of galipot conversion into diverse products and the possibility of exporting high value-added products, the most important strategy to be considered is to optimize the value chain of products by strengthening of the marketing. Planning for the production of products with export capability should also be prioritized.

Background and Objectives: Nowadays, production of wood-based panels with lower density (about 25% lower compared to those conventional panels) gained more interest all over the world due to increased price of raw wood and the market needs for lightweight panels. Several methods and materials were used to produce lightweight panels in recent years. Among all, using of light and voluminous materials like polymeric granules have attracted more interest to reduce the panels density. Simultaneous use of the unique properties of two or more conventional wood products can influence the final characteristics of the lightweight wood-based panels. The aim of the current study was the production of lightweight wood-based panels using wood fiber as the surface layers and a mixture of wood particles and polystyrene granulate as the core layer. A comparative study was done to see the effect of two types of polystyrene granules (expandable and pre-expanded granules) and the granules percentage on the physical and mechanical properties of the lightweight wood-based panels. Materials and Methods: Hybrid-lightweight panels (520 kg/m3) were produced using wood fiber as surface layers and a mixture of wood particles and polystyrene granulate as core layer. For constructing the panels, two kinds of the granules (pre-expanded and expandable granules) were used with different percentage (5, 10 and 15% based on oven dry mass of wood coarse particles). In this study, mechanical (bending strength, modulus of elasticity, internal bond, and screw withdrawal resistance) and physical properties (thickness swelling and water absorption) of the panels were evaluated. Results: The results showed that the physical and mechanical properties of panels were improved using polystyrene granules compared to that of reference panels (no granules). The modulus of elasticity was nearly doubled in case of pre-expanded granules, while other properties were nearly the same. Increasing the granules content up to 15 percent has a significant effect on the internal bond value, edge screw withdrawal resistance and physical properties (thickness swelling and water absorption). Thickness swelling and water absorption were significantly reduced with substitution of wood particles with polystyrene granules. Conclusion: The results showed that with increasing of polystyrene granules, the internal bond and screw withdrawal resistance were improved. The results also showed that the granules types (expandable and pre-expanded granules) had no significant influence on the panels’ properties, except the modulus of elasticity and internal bond. As final conclusion, using of expandable granules can be favored for panels’ production due the elimination of pre-expansion process and increased binder effectiveness.