فصلنامه پژوهشهای علوم و فناوری چوب و جنگل
سال بیستم شماره 1 (بهار 1392)

Heat treatment is often used to improve the dimensional stability of wood and wood products. The aim of the study was to investigate the effects of heat treatment on the mechanical and physical properties of eucalyptus wood. Wood samples were exposed to temperature levels of 130, 160 and 190 ˚C for time spans ranging from 3 to 9 hour. Mechanical properties including compression strength parallel to grain, compression strength perpendicular to grain, bending strength, modulus of elasticity in bending, janka-hardness and shear strength and physical properties including oven-dry density and swelling of heat-treated samples were determined. The results showed that the values of density and swelling decreased with increasing temperature treatment and treatment times. Also the results indicated that treated samples had lower mechanical properties compared to the control samples. In addition, increase in temperature and durations decreased the mechanical properties.

Deinked pulp of mixed office waste was used to improve different properties of CMP made by Populus alba species. CMP pulp and DIP of mixed office waste (MOW) were produced according to the industrial standard (Mazandaran Wood and Paper Industry) and flotation, respectively. The pulps were refined to reach 300 ml.csf, after which hand sheet were produced as mixed with imported long fibers and their physical, mechanical and optical properties were measured. Results showed that by increasing DIP of mixed office waste (MOW) content in blended pulps, optical paper properties improved but strength properties slightly decreased. Ranking of treatment based on normalization calculations showed that papers with 80% Populus alba CMP, 15% deinked pulp and 5 imported long fiber had the highest rank and on the other hand the best condition in paper properties. However using 15% DIP of mixed office waste blended with CMP pulp of Populus alba and little content of imported long fiber resulted to produce suitable newsprint.

Nowadays, Study of diversity and composition of woody species is one of the important subjects in order to understanding the changes forest ecosystem and variability in the world. The aim of this study is to evaluation the relationship between the diversity and the richness of woody species and physiographical factors which are important in distribution and establishment of plant species. A systematic random sampling method (200×250 meters) was applied to collect field data. The 84 plots were designed and established. Also, the plots were squares of 40×40 (0.16 ha) meters dimension in the forest located in two basins of Salas babajani and village of Babakoseolia in kermanshah province. Factors such as elevation, slop, aspect, forest type and diameter of species were recorded in each plot. Then via using section level sum and total basics in each sample plot, calculated the amount of eight indicators of diversity and even ness (Simpson, Hill, Shannon, even-aged number of species, smoothness of Simpson, Kamarago, smith, Wilson and Nee). Two indicators of richness (Margalef and Menhinick) by using of total basal area species and total number of tree in every sample plat were calculated in general nine woody spices were determined in studied region and 3 indicator as number of even-aged species smith Wilson and Margalef were recognized as the best indicator of heterogeneity evenness and richness, respectively. the results showed that the highest diversity, richness belong to the site with higher elevation and northern aspect with 30% slope the highest amount of evenness belong to the lower elevation and southern aspect there is no differences in indicator of Smith-Wilson for different slope classes.

In this research nutrient return and nutrient retranslocation in Acer velutinum in some parcels of district 1 from watershed number 7 where, Acer velutinum show preferred establishment and distribution, were investigated. In each sampling plots, taken randomly in appropriate sites of Acer velutinum, soil samples, fresh and senescent leaves were taken and then C, N, Ca, Mg and P were analyzed. The statistical analysis showed that all of the variables amongst the soil, the fresh and senescent leave have significant differences. The amount of C, N and P was higher in fresh leaf compare with senescent leaves and in fact they retransloct more, whereas Ca and Mg were returned more by litter to the soil. Apart from N and Ca the process of nutrient in the soil was similar to what has happened in the leaves. The type of nutrient return and nutrient retranslocation suggests the higher require of Acer velutinum to nutrient elements. On the other hand, the quality of the leaves of Acer velutinum also is a positive role in increasing soil fertility.

The crude oil price fluctuation have highly affected to world countries economy. The wood products price and its major exporter countries is difference dependence on OPEC oil price. Inflation rate and correlation between the OPEC crude oil price and the price of wood and paper products are demonstrative of the scale of dependence. Primary datasets were prepared from Central Bank of the Islamic Republic of Iran (CBI) and FAOSTAT online database and OPEC Annual Statistical Bulletin. Export price of major exporter countries and price of OPEC oil were evaluated by single payment formula and coefficient of determination. Also, exportation point of wood and woodwork in Iran and price of OPEC oil were compared by neural network model. Experiment results showed that the OPEC crude oil price and the price of wood and paper products were increased and its correlation is positive by high coefficient of determination. The correlation between the OPEC crude oil price and the price of paper and paperboard are more than other commodity. In the other hand, growth rate of fuel wood is more than other products. The correlation between OPEC crude oil price and exportation price of Russia and Sweden is more than other countries. Inflation rates of wood and paper products in Russia and Sweden are like OPEC crude oil price and its annual rates of change in price are the most. Result of neural network model is showed that exportation point of wood and woodwork in Iran are similar to crude oil price, nearly.

The porpurse of this research is determination of effect of old magazines deinked pulp in compound Poplar on the paper properties and also determination of the best appropriate percentage mixture of OMG deinked pulp with poplar CMP pulp. Provided poplar samples from Bahramnia research & educational forest in Shastkalateh of Gorgan, were cooked with CMP method by sodium solfite and Sodium carbonate. Then a stage of refining was done to achive about 300 of consistency. OMG recycled papers were deinked by Flotation method and then they were bleached by Hydrogen Peroxide. Ultimately deinked recycled pulp was mixed in different percentages with CMP pulp and imported long fibers. Then handsheet papers were examined from point of optical and mechanical properties. The results shown that deinked mechanical pulp is a good alternative material and it can to be replaced with a part of imported long fiber and CMP pulp. The best composition of pulp was determined for 80% CMP, 15% L.F and 5% deinked OMG.

Soda is the most important pulping process for production of semichemical pulp from agricultural residues especially bagasse. Technical specifications and characteristics of fluting paper produced from agricultural residues are similar to those produced from wood species by using common NSSC process. In the present study, the potential of semichemical soda bagasse pulp and the comparison of its physical and mechanical properties with hardwood NSSC pulp produced in Mazandaran Wood and Paper Industries (MWPI) at laboratory scale were investigated. 8 percent active alkali and cooking time of 20 minutes at 160 °C, was selected as optimum condition for making semichemical soda bagasse pulp with pulp yield of 64.5 percent and kappa number of 74. Properties of fluting paper from semichemical soda bagasse pulp were compared with hardwood NSSC pulp. It was shown that flutting paper produced from soda bagasse pulp had much superior physical and strength properties than hardwood NSSC. As a result, in the case of using bagasse semichemical pulp for production of fluting paper in mills like MWPI, not only stronger paper may be produced but also significant reduction in forest based wood consumption can be achieved.

The aim of this study is ecological investigation of Cerasus mahaleb (L.) Mill relation to some physiographic and edaphic conditions in this sites (10 ha area). in order to achievement to the most important factors on distribution of cerasus mahaleb (L.) Mill (PCA) method was used. Results showed that most important factors affecting on the establishment and distribution of Cerasus mahaleb (L.) Mill were Elevation, Ca, aspect and lime, slope, N, P, pH, clay, stony percent, organic matter, silt, K and C.