Journal of Wood and Forest Science and Technology
Year:2013 | Volume:20 | Issue:2|Papers Count:10

To investigate the physiographic factors and related soil physico-chemical and biological characteristics, 268.7 ha of Noushahr khanikan forests were studied on May 2012.60 soil samples were taken from 0-10, 10-20 and 20-30 cm depths with systematically random method. The physiographic factors including slope, aspect and altitude recorded in soil sampling location. Soil acidity, bulk density, saturation moisture, organic carbon, total nitrogen, soil texture and biomass of earthworms were measured in the laboratory. The earthworms were collected simultaneously with the soil sampling by hand sorting and classified to epigeic, anecic and endogeic ecological groups. Site slope were divided to four classes (0-20, 20-40, 40-60 and 60-80%) and altitude divided to three classes (100-150, 150-200 and 200-260 m). Analysis of variance is indicating acidity, bulk density, saturation moisture and soil texture had significant differences among aspects and slope classes. Nitrogen and carbon to nitrogen ratio values showed significant differences among aspect and slope classes, respectively. Altitude classes showed no difference in viewpoint of physico-chemical properties. Epigeics number and biomass had significant statistical differences among aspect and slope classes. Epigeics found in soil superficial layer (0-10 cm). The most activity of anecic and endogeic groups was visible in more beneath depths (10-20 and 20-30 cm).

Density (i.e. number of trees per hectare) in a forest stand shows current status of the stand and its monitoring is important to assess the stand’s changes. On the other hand, application of distance methods is spread widely to estimate stand density, especially in woodlands. This research was aimed to apply and compare LTS and LIS methods, as important distance methods, to estimate wild pistachio density in Zagros forests, Iran. A 45 ha plot was selected in Wild Pistachio Research Forest in Fars province for this purpose. A pilot experiment showed that the effective length of transect was 167 meters in LTS method that was applied in 10 sampling points and the perpendicular distances of the wild pistachio trees less than 46 meters were measured in these transects. Also in LIS method, a preliminary inventory showed that the transects applied in LTS method was suitable for this method. The results showed that the density of wild pistachio trees was 21.1 with 95% Cl=16-26.2 and the mean density was not also different from the true density (19.4 trees ha-1) significantly. While density was 26 in LIS method with 95% Cl=18.7-33.3 and it was significantly different from the true density. Consequently, LTS method was more efficient for wild pistachio density estimate in the study area and it is suggested to assess this method in other parts of Zagros forests.

In this study, the effects of zinc borate with or without UV absorbent and antioxidant on the durability of wood-high density polyethylene (HDPE) composites were investigated during artificial weathering. colorimetry and tensile strength were determined after 0, 500, 1000 and 1500 hrs. Fourier Transform Infrared Spectroscopy (FTIR) and Differential Scanning Calorimetry (DSC) analyses were also carried out before and after 1500 hrs accelerated weathering. The results indicated that zinc borate had no effects on the weathering resistance of wood-HDPE composite. The use of antioxidant increased surface degradation of the composite evidenced by FTIR and DSC analysis. The color and tensile strength stability and FTIR analysis indicated that the composite was protected by UV absorbent.

In this study the effects of separate and combined refining of Hornbeam (Carpinus betulus) CMP and imported long fiber (LF) pulps on the prepared hand sheets properties is evaluated in two states. In the first state, Hornbeam CMP and long fiber pulps were separately PFI-milled to reach to 250-400 ml, CSF (261, 309, 362 and 410) and 400-600 ml, CSF (410, 474, 530 and 590), respectively. Then, they were mixed at the ratio of 80/20 and laboratory hand sheets were made and their physical, mechanical and optical properties were determined. In the second state, the average freeness value for each mixture of the pulps from the first state (261 Hornbeam+410 LF, 309 Hornbeam+474 LF, 362 Hornbeam+530 LF, 410 Hornbeam+590 LF) was calculated and the real freeness value for each mixture was reached to the calculated one using combined PFI-milling. Hand sheets were then made from each mixture of the pulps and their physical, mechanical and optical properties were determined. The comparison of the results showed no significant difference at 1% experimental error level between properties of the papers prepared from both states.However, higher PFI revolutions improved the properties of papers. On the other hand, it was observed that combined refining of the pulps led to saving in refining energy use and, thus, is recommended.

Nowadays, the great transformation with expansion of competition is observed in different fields, especially in markets. So, it is necessary to do market research for all countries and companies which intend having informed presence in market. The great potential for consuming this product would request the necessity of investigating the processes of its consumption.Consuming market of this product has been investigated by means of regression analysis of the past consumption and the market share of MDF among other wood pressed sheets. It has been anticipated that the process of consumption increase in the future years would continue with high speed and reach about 60% of the market share of wood pressed sheets in 2014. Study of MDF consumption market would request the necessity of investigating effective standards on that’s acceptability between consumers. For this seems has designed questionary and completed by consumers and resulted to choice ten effective standards on MDF consumption in the country. Attentive analysis of variance, effective standards on MDF consumption market with a view to Iranian consumption haven’t similar importance and their effectives have different. The mainest reasons for acceptability of MDF among Iranian consumers are aesthetics features and resistance to moisture.

Minimizing of logging residuals has economic importance. In this research, volume and characteristics of logging residuals were studied in parcel 237 with 41ha from Asalem-Nav mountainous fagetum forest area. In this parcel silviculture method and logging system is single selection and assortment. The systematic sampling and line intersect method was used to estimate volume, weight, number and quality of logging residuals with twenty 100 m sample lines. Huber formula was used to measurement of each piece volume. Volume, weight and number of logging residues per hectare were estimated 3.6 m3, 2.5 ton and 233 pieces, respectively.Averages of volume, weight, length and middle diameters of pieces were estimated 0.02 m3, 15 kg, 1.5 m and 10 cm respectively. Roughly 65 percent volume of logging residue were recognized first class quality and without decay and knot. Ratios of logging residue volume to number of tree felling (R/N), log volume (R/L) and sum total of tree felling dbh (R/D) were estimated 0.58, 0.17 and 0.01. This amount of logging residuals is considerable and useable in wood industries. So export of those can have economic value.

In this research, the decay resistance of commercial polypropylene-pistachio twigs flour composite with and without pigment was investigated against the white-rot fungi 'Trametes versicolor ' and the brown-rot fungus ' Coniophora puteana'. The composite specimens containing 60% pistachio twig flour were exposed to a decay test according to modified ASTM D 1413 standard for 3 months. The results showed that the composite could be decayed. With analyzing the data, it was shown that the weight loss of the composite due to decay by C. puteana was significantly higher than that for T. versicolor however, the presence of the pigment did not have any significant affect on the weight loss of the composite. Scanning electron microscopic (SEM) showed cracks and voids in the control (unexposed samples), as well as the fungal hyphae penetration into the samples decayed by C. puteana. Nevertheless white rot fungi create a surface decay.

In this study, present status of woodworking workshops in size, storage of raw materials and storage of products of woodworking workshops, raw materials and machinery were investigated. Investigation was obtained through 127 questionnaires from wood working workshops in Golestan province that are active cabinet manufacturing, office and home furniture, and home decoration.Analyze of data showed that 52% of wood working workshops are small and then most woodworking workshops are very small. Most woodworking workshops have been launched by one person with little capital and all woodworking workshops are private. 62% of woodworking workshops do not have raw materials warehouse and 75% do not have woodworking products warehouse. Main cause of lack of raw material and wood products warehouse is lack of adequate capital.40% of the carpentry use workshop space for storage of raw materials.38% of woodworking workshops use types of raw materials, 34% of their use only spruce and 18% of their use MDF and coated particle board. Main reasons of use of different materials are quality and costomer.79% of main wood machinery is made in Iran but in the case of small electrical machines are mostly foreign.

The alpha cellulose of softwoods (microfibers) was turned to cellulose Nano fibers using ultra-fine friction grinding process, as a simple, fast and one-step downsizing method. The effect of grinding on fiber diameter, crystallite size, crystallinity, suspension stability, together with the transparency and air permeability of sheets made from micro-and Nano fibers was investigated. The average diameter of microfibers and Nano fibers was 33±10 µm and 28±11 nm, respectively. The results of X-ray scattering demonstrated that the crystallinity and crystallite size of microfiber was 79% and 5.1 nm, respectively. During grinding process, the crystallinity and crystallite size decreased to 73% and 4.6 nm, respectively. The suspension of microfibers was unstable over checking stability time, while the nanofiber suspension had a long-term stability. The air-permeability of microfiber and Nano fiber sheets was 320 and 1.06 mmPa-1s-1, respectively. The qualitative transparency of microfiber sheet was distinguishably lower than that of Nano fiber sheet.

In this study a cellulosic and environmentally friendly nano material has been used as a reinforcing agent of CMP pulp of Mazandaran pulp and paper factory (used for producing liner board). The purpose of this study was to evaluate the influence of the suspension mixing time on the final paper properties. So, the chemi-mechanical pulp suspensions (with concentration of %2 and freeness of 250 CSF) included cellulose nanofiber of 5% wt were prepared and mixed on the magnetic stirrer for 0.5, 1, 4 and 8 hours at 25oC.The resulted suspensions were drained by means of vacuum filtration. After draining, the wet handsheets were pressed and then dried in the oven at 100oC for 24 hours. The results showed that at the first phases (around 1 hour) air permeability decreased and strength properties of paper increased with the increase of mixing time. Although, with increasing of mixing time more than 1 hour, the trend of paper properties changed completely inversely. It can be attributed to the change of the interaction between fiber and cellulose Nano fiber at longer mixing time.