Journal of Wood and Forest Science and Technology
Year:2016 | Volume:23 | Issue:1|Papers Count:16

Background and objectives: Resistance to liquid sorption is important in various paper and board applications which would be contributed by chemicals as hydrophobizers of the structures. The hydrophobization process is called; Sizing, that could be done as internal and surface treatment with prevalence happening on internal sizing. Necessity and inspirations of recycled fiber together with bringing of required properties in the product, predominate engineering layering of paper and board production to supply and compromise requirements. The aim of this study focused on internal sizing effects of alkyl ketene dimer in multilayered cardboard constructed of heterogeneous and diverse fiber in its different layers.Materials and methods: Multilayer cardboard (330 g/m2) patterned on the engineered heterogeneous layering of recycled and virgin pulp was internally sized by Alkyl Ketene Dimer (AKD) as 1% based on the pulp O.D. in two papermaking conditions; neutral and alkaline. Then, the effects of the considered conditions on the recycled-virgin board properties were evaluated such as top and back layers Cobb test, bulk, gloss, surface roughness and strength criteria.Results: The cellulose reactive nature of cationic alkyl ketene dimer led to improvements in strength and water sorption of the sized board compared to the unsized one. Resistance to water sorption in the fibrous network have occurred after the fiber bonding and have not been as an effective obstacle in fiber bonding. At alkaline condition, all of addressed properties, especially water sorption and strengths of the board, improved considerably compared to the neutral. In alkaline condition, regarding to more ionization of fiber surface carboxylic groups, more and better bonding is occurred between fiber and AKD, as a cationic sizing agent, resulted in a reduction in water sorption and provided more bonding ability among pulp ingredients. On the other hand, higher swelling of the ingredients together with the higher cationic demand of the fiber at alkaline situation, enhanced fines retention and fiber bonding which results in the board surface smoother.Conclusion: The sizing treatment of multi-layer cardboard by AKD reduced its water sorption in top and back layers and its surface roughness. Increment of bulk and strength properties of the cardboard include tensile, bending stiffness and ply bond were observed as a sizing results, with no effect on the duplex cardboard gloss. The noted improvements were attributed to the bonding enhancement among fibers and also the board layers via AKD, followed by sizing agent curing at drying section lead to the hydrophobic creation in the board structure and lower water sorption.

Background and objectives: Cationic polymeric retention aids are usually used to increase fines and filler retention in papermaking but paper strengths are impaired at increased level of filler retention due to loss in fiber to fiber bonding. Synthesizing of cationic fiber fines and its utilization as retention aids in comparison with Cationic Polyacrylamide (CPAM), was investigated at present research.Materials and methods: Fines were prepared from bleached softwood kraft pulp after extended refining (40000 PFI revelotions) up to about 50 mL, CSF, followed by screening with water jet on 200 mesh screen. Cationic fiber fines were prepared by using monomers of cationic ester amine salt.Results: The results of cationic fines analysis by FTIR, kajeldal nitrogen content, and Zeta potential indicated that, the cationic groups were generated in the fiber fines and adsorbed on fibers and fillers in the process of papermaking.Conclusion: The effects of using different amounts of 0.3, 0.9, and 1.5% cationic fiber fines, in comparison with 0.1, 0.2, and 0.3% CPAM, based on OD CMP pulp, have been investigated on filler retention as well as produced handsheets properties. The results showed that produced handsheets with using of cationic fines versus cationic polyacrylamide had higher strength properties. In addition, using a mixture of cationic fines and CPAM, led to further improvement in the strength properties of paper.

Background and objectives: In order to utilize nanoparticles in plant science, basic physiological research is required. So far, most investigations on nanoparticles effects on plant performance have focused their attention on grasses and crops while information on woody plants is very scarce. In this study, effect of silica nanoparticles on growth and physiological behavior of hawthorn (Crataegus aronia L.) seedlings - one of the most important species of Zagros habitat- was examined.Materials and methods: a greenhouse experiment was set up following a completely randomized design with 4 treatments and 5 replicates. The treatments included soil irrigation with tap water (without nanoparticles) and three different concentrations of silica nanoparticles (NPs) - 0, 10, 50 and 100 mg.l-1 - every three days until reach field capacity for a total period of 45 days. Assessment of gas exchange parameters (net photosynthesis, stomatal conductance and transpiration rate) during the experiment period as well as some physiological changes (leaf relative water content and xylem water potential) and biomass allocation (roots, stems and leaves) were measured at the end of experiment. Scanning electron microscopy (SEM) was used to study the presence of nanoparticles on the root epidermis.Results: Although nanosilica on hawthorn trees partially reduced plant water potential (more negative), leaf relative water content was not affected by the SiO2 NPs treatments. Silica nanoparticles significantly increased the gas exchange rate during the experiment, which finally led to an increase of plant biomass - especially of roots. Total biomass of seedlings subjected to irrigation with 100 mg.l-1 was 40% higher compared to control plants. The evaluation of SEM images confirmed massive presence of silica nanoparticles on root epidermical surface.Conclusion: In general, it can be stated that silica nanoparticles improved the physiological activity of plants, which resulted in high biomass accumulation in hawthorn seedling. Further studies are required to understand the mechanisms behind these responses. Genomic studies (gene and protein expression) might be considered by plant biologists as starting point to achieve this goal.

Background and objectives: Equilibrium moisture content (EMC) is one of the major indicators in wood sciences that its determination and investigation in the different locations prevents the losses of wood products quality by meteorological parameters. This study was conducted to present a mathematical model according to a correlation between EMC and spatial variables (latitude, longitude and altitude).Materials and methods: In this study, 93 synoptic and climatology stations during a 26-year period were selected and then the regression equations of uni- and multi-variable between EMC and the spatial variables were fitted to the experimental data. The distribution of stations was suitably selected to cover all the geographical and climatic zones in the country. The constructed equations were evaluated using determination of coefficient (R2), root mean square error (RMSE), and mean bias error (MBE). In initial and second steps, the equations were considered with the highest R2 values and the lowest RMSE values, respectively. Under-estimation and over-estimation of the equations were determined by negative and positive MBE values, respectively.Results: Results showed that the offshore and cold climate had more EMC than the central and arid climates of Iran. The highest EMC was belonged to winter months, initial months of spring and final months of autumn. Analysis by spatial variables revealed that use of two-variable equation of latitude-altitude represents better than the uni-variable equations. However, three-variable analysis showed more exact results compared to uni- and two-variable equations. A good finding was found in the warm months using three-variable analysis.Conclusion: It seems that the suitable solution to investigate EMC with spatial variables was studying the regional scale, considering the climatic conditions, near and further to water resources and finally presenting a reasonable model for specific climate of the each area.

Background and objectives: Thermal degradation is therefore, one major limitation frequently encountered when using natural fibers as reinforcement in a polymeric matrix. Natural fibers are mainly composed of cellulose, hemicelluloses, and lignin which exhibit different degradation behaviors. In this study, the effect of residual lignin content on the thermal and morphological behavior of polypropylene-kraft pulp composites was investigated.Materials and methods: Hornbeam wood (Carpinusbetulus) chips converted to Kraft pulping in different effective alkali (15, 20 and 25%) and fixed levels of cooking time (120 min), temperature 170 C and sulfidity 25%. Then residual lignin content of these pulping was determined according to the TAPPI standard. For manufacturing the composites, kraft puplp and polypropylene at mixing ratio of 50% with 4 phc MAPP were mixed at 180 °C, 60 rpm in a co-rotate extruder. Finally, the samples were made by injection molding. Then, the thermal properties of composites such as weight loss, melting temperature and degree of crystalinity was studied by thermogravimetric analysis (TGA) and differential scanning calorimetry (DSC). Also, the morphological experimental were examined by scaning electron microscopy (SEM).Results: Results indicated that with increasing of effective alkali (from 15 to 25%), the values of wight loss, melting enthalpy and degree of crystalinity were increased, however, the melting temperature were decreased. Results of SEM indicated that the interface quality decreased by increasing of effective alkali and decreasing of residual lignin.Conclusion: Based on the results, it can be said that lignin extraction improves the thermal stability of polypropylene-kraft pulp composites due to the crystalline formation and increasing thepolymer chains mobility.

Background and objectives: One of the major problems in the industrial wastewater treatment plant is sludge volume, which requires to providing economic and environmental solutions. The use of natural compounds is preferable to the chemical compounds in the sludge treatment process, environmentally. For this reason, experts are trying to find a suitable material for replacement. Yousefi et al (2012) evaluated the efficacy of chitosan natural polyelectrolyte as a coagulant to elimination of water opacity. The results showed that chitosan has little effect on water pH and its efficiency is better in elimination of high opacity.The chitosan is one of the natural materials. The purpose of this study was determine of optimal pH and concentration of the alum, chitosan and early preparations for simultaneous use in a pilot-scale to improve dewatering sludge. Also, the effect of these treatments was measured on turbidity, color, COD of water sludge Filtration.Materials and methods: For this purpose, from determine of filtering time and measuring of moisture content was used for assay of dewatered sludge capabilities. In this regard, 10 percent alum solution were prepared by dissolving 10 g from aluminum sulfate in one liter of distilled water. To prepare of the chitosan solution, 100 mg from chitosan powder is carefully weighed and dissolved by 10ml chloric acid 0.1 M and then its volume was bring up to 100 ml. acidity of aqueous sludge adjustment by sodium hydroxide and sulfuric acid in the range of 4 to 9. Afterward the constant concentration of alum, chitosan and chitosan-chitosan was added. Ml 50 dewatering time was determined by Buchner funnel, filter paper and vacuum device and water content was determined by oven-dry.Results: The results indicated that the optimal pH for alum, chitosan and alum-chitosan is 5, 7 and optimal concentrations 800, 90 and 600-70 ppm, respectively. By applying this treatment in optimal conditions the best treatment to achieve the minimum dewatering time is alum-chitosan treated with pH 7 and 70-600 ppm consumption. Also, the best treatment for reducing color, turbidity and COD of sludge filtered water is treated alum with concentration of 800ppm and pH 5.Conclusion: Dewatering time of the control and treated with alum increased with increase in pH from 4 to 9. Dewatering time in about the samples treated with chitosan, especially alum- chitosan showed less sensitive to pH. So, the alum treatment had little effect on the color and COD at pH=7, whereas the opacity decreased to 24 percent. The chitosan had highest effect on COD and then turbidity and color. Alum-chitosan treatment has a significant impact on turbidity and COD.

Background and objectives: Awareness of species diversity changes in effect of forest management and utilization, will give us valuable information from forests stand that help us in correct decision making, future planning and sustainable management. The aim of this study is evaluation of tree species diversity indices in natural forest stands compared to managed forest stands in a part of district one and two Shast Kalate forests of Gorgan.Materials and methods: The circular plots with 0.1 ha area were collected in a systematic random sampling design. In each plot, we recorded species and their diameter for all trees with a diameter at breast height (D.B.H) greater than or equal to 12.5 cm and richness, evenness and diversity indices computed in all plots. Also, the independent T test was used for comparing richness, evenness and diversity indices between natural and managed forest stands. Also, the rarefaction method was used for accumulation pattern of species.Results: The results of statistical test showed that differences in Menhenick and Margalef richness indices, Simpson Reciprocal (Hill), Shannon-Wiener and common species diversity, Simpson, Camargo, Smith-wilson and Modified nee evenness indices between managed forest stands and natural stands forest in 95% probability are significant that represented the correct management and positive trend in managed forest stand.Conclusion: Also this result expressed that forest management and utilization were preserved the tree diversity in this study area and managed forest didn't have distance from evolutionary trend.

Literature and purpose: the unique properties of poppulus species like fast-growing, low density, bright wood, noticeable production of wood in the period of Exploitation, high yield pulp, suitable refineable, and acceptable paper strength lead to as suitable species for papermaking industry. This study was aimed to determine the best conditions for producing the bleachable pulp from Populus deltoids. For this purpose, the best cooking conditions include yield changes, kappa number, cellulose degree of polymerization, and brightness were investigated.Materials and methods: The wood species from Dr. Behramnia research forest located in Shastkalat region in Goragan were obtained. The wood obtained were turned in wood chips, air dried and their moisture content was determined and finally used for preparation Kraft pulp. The cooking conditions were l/w: 6/1, temperature 170 °C, sulfidity 25%, 18 and 20% active Alkali (AA) charge and cooking time 60, 90 and 120 minutes for produced bleachable pulp with yield near 50% and kappa number between 15 to 20.Results: the results of Populus deltoids kraft pulp yield showed that pulp yield with the level of 18 and 20% alkaline and 60 min. was high than other treatments.Also, the highest kappa number was achieved with 18% alkaline and 60 min. and lowest kappa number was founded with 20% alkaline and 120 minutes. Among these treatments, maximum DP with 18% alkaline and 60 minutes and minimum DP with 20% alkaline and 120 minute were achieved. Finally, maximum unbleached pulp brightness was related to treatment with 20% alkaline and 90 & 120 minute and minimum brightness with 20% alkaline and 60 minute was achieved.Conclusion: The kraft pulp with cooking conditions: AA 20%, time 60 min, sulfidity 25%, L/W: 6/1 and temperature 170°C from between taken various cooking was chosen. The yield 49.66%, Kappa number 15.2, degree of polymerization 1700 and brightness for unbleached pulp was 38.22 % ISO.

Background and objectives: Undesirable mechanical properties of soil such as swelling that causes many problems to forest roads often observe in soils with high clay content. Soil volumetric changes that are the result of changes in soil moisture content causes high damages to forest roads. This shows the importance of investigation about applying techniques to improve the swelling properties of these soils. Therefore, in this study, the effect of an ionic stabilization material (CBRPLUS) on controlling the swelling behavior of soil as the forest road material was investigated. Swelling and swelling pressure tests were performed on natural soil samples (control samples) and samples that treated with company proposed percentage (0.0096%).Materials and methods: In order to test swelling potential and swelling pressures, samples were prepared with optimum moisture determined by compaction test and were compressed by static compaction method and then moved to consolidate apparatus.Results: The swelling potential for control and treated samples with company proposed percentage (0.0096%) were 17.5% and 16.5% respectively, which shows 5.71% reduction in swelling potential. Also, the swelling pressure for control and treated samples with company proposed percentage (0.0096%) were 570 and 510 kPa respectively, which shows 10.52% reduction in swelling potential by adding the ion stabilizer.Conclusion: Therefore, adding the proposed dose of this substance could reduce swelling and swelling pressures of soil. But, that the amount of swelling and swelling pressure reduction was not as high as claimed by producing company. Therefore, this matter with proposed dose has no significant effect on improvement of soil swelling properties.

Background and objectives: The purpose of this study was the effect of seed pretreatment salicylic acid on germination traits of Pinus eldarica Medw. Seed under drought stress. In this relations the similar investigations with forest species is rare.Materials and methods: The experiments were carried out as factorial based on completely randomized design with 3 replications. Pretreatments including combination of 4 levels of salicylic acid (0, 0.5, 1 and 2 mM for 72 hours) was subjected to 5 levels of drought stress (0, -2, -6, -10 and -14 bar by Polyethylene glycol 6000). Then the seeds were located in germinator for 40 days at 20°C, 65% relative humidity and 8.16 hours, dark/high photoperiod.Results: In all pretreatments, by increasing drought stress, germination percent, germination index, germination energy, germination speed, kotowski coefficient of velocity and seed vigor index were reduced and mean germination time increased. Germination of control seeds was ceased in osmotic potentials>-6 bar, but seed pretreatment (by all applied concentrations of SA) even up to -14 bar improved germination percent and other studied traits. The highest germination percent (88.34%) was observed in pretreatment of 1 mM SA and drought stress of 0 bar, and the best germination percent (45.27%) at -14 bar level of drought stress was related to pretreatment of 1 mM SA.Conclusion: regarding to application of P. edarica seedlings in plantations and urban and rural green spaces of arid and semi-arid regions, SA seed pretreatment can improve its seedling production efficiency in nurseries of these regions.

Background and objectives: Montpellier maple (Acermonspessulanum sub. Turcomanicum) is one of the five subspecies of Acermonspessulanum in Iran that has been distributed in the north-east of the country, from Gorgan to North of Khorasan. The lack of a revival in natural habitats and the problems due to the drought caused the loss of many maple trees in Iran. Furthermore, a high percentage of seeds are hollow and injured after maturing. Also, viability of seeds is very low due to seed dormancy that will be less after a period of cold stratification. Regeneration of linden species (Tilia begonifolia) also is faced with many problems in the province forests. In many cases, collected seeds from the forest floor seem to be healthy and mature despite of spending necessary stratification treatments, and having suitable viability but are not able to reach to the healthy and successful seedlings. This study aims to investigate and identify factors causing damages the seeds of these species in order to control them in the future.Materials and Methods: Montpellier maple Seeds were collected from 11 native trees with superior morphological characteristics from Siahmarz-kouh located about 18 km from southeast of Gorgan and Zarrin Gol located at 17 km from southeast of the Aliabad city, Golestan province, Iran from outer part of the crown and in different ways. Then, the primary characteristics of seeds were calculated. Seeds viability was determined using tetrazolium after collecting and six months after cold stratification. Flotation test (24 hours immersion in water) was used to determine the value of the pure seeds and empty and infested seeds. Seeds pest of Montpellier maple was identified before leaving the pest from the seeds, by trapping 3 weeks on 20 trees and storing collected seeds in desiccators and using valid identification keys. Seeds were cultured on the PDA medium and after sterilizing with sodium hypochlorite 5% and removing the infected parts and fungi were identified. In order to identify harmful factors, seeds of linden tree were collected randomly from Touskestan forest at an altitude of 700 meters above sea level and then, their surface were sterilized in sodium hypochlorite 5% for 3 minutes. After washing and drying, the seeds were cultured in the dishes containing PDA medium (20g agar, 20g sugar, 300 g potato extract and distilled water 1000 cc) in 5 replications and were incubated for 24 to 48 hours at 25 °C. Examples of grown fungi were transferred on water agar medium (containing 20 g agar, 1000 cc distilled water), and were placed at incubator for 24 to 48 hours, then, the end of the grown hyphae of fungi was removed and were re-cultured in PDA media in order to purify and identify fungi completely.Results: The results of this study showed that rotted and hollow seeds of Montpellier maple are 50-75%. Anthonomus Eugenii pest was identified from Curculionoidea family that its damage has been evaluated 35-50%. Investigations showed that viability of the remaining seeds was remarkably reduced (2-12%) after period stratification. Also, Fusarium oxysporum and Alternaria alternata fungus were identified on Montpellier maple seeds that cause rot, reducing seed viability and damping-off diseases. Associated fungi with Tiliabegonifolia seeds were identified through contamination test including Fusarium oxysporum, Penicillium implicatum and Alternariaalternata that can potentially reduce the viability and cause severe damage to the seeds in later steps i.e. seedlings.Conclusion: These results demonstrate that identified factors in the seeds of these two forest species are the basic reasons of lack of regeneration, and loss of the seeds viability.Control of thesefactors enhance the quantity and quality of seeds and therefore, natural regeneration of this species.

Background and objectives: Parks and green spaces are from landuse that its distribution and dispersion in the city is very important. Due to the lack of comprehensive planning at the national level, urban services uses among green spaces have encountered problems such as deficiency of green space per capita, inappropriate distribution and location and lack of prediction of this spaces in cities. Due to this problem, require the construction of urban green spaces including urban forest parks and selecting new sites for afforestation will be necessary.Material and methods: In this study, for the first part: Using GIS capabilities, arboreal green spaces per capita, including parks and gardens planting trees and tree stands can be used for public, in different regions of Mashhad, evaluated using satellite images and regions were prioritized in terms of per capita. The results showed that region 3 has the lowest arboreal green space per capita. In the second part: Locating of urban forest park, with considering its criteria on aspects of recreational, ecological and structure were investigated. In the first layer data maps were produced, then standardized using various fuzzy functions. Then the standardized maps multiples own weights got from AHP, and were combined using WLC method.Results: Result maps, showed suitability of Mashhad region 3 lands and the most appropriate sites for creating of urban forest parks. The results showed that barren lands and agricultural lands, respectively, have much suitability compared to other land use because of the ease of conversion to urban forest parks. Also areas that are closer to the city center, have a high suitability for creating an urban forest parks, because of the proximity of residential, education, tourism and recreation uses and also the ability to create boundaries and privacy, and improve the quality of urban areas and proximity to air and noise pollution sources.Conclusion: The results of this study can be used in future projects and plans due to weak condition of Mashhad city in terms of green space per capita and transmittal related to the construction of urban green space according to the criteria and area potential.