Journal of Wood and Forest Science and Technology
Year:2009 | Volume:16 | Issue:3|Papers Count:10

Bending and compression strength of Paulownia fortunie wood grown in educational and research forest located at Shastkalate, Gorgan were studied. Paulownia trees were selected among five years old plantation. Sampling spot was conducted following standard procedure. Trees were cut into logs, which were then cut into 6 cm thickness wood blocks based on geographic directions. Wood blocks were divided into two groups. One group assigned as wet group and another group of wood blocks was air dried until their equilibrium moisture content reached to 8.6% and assigned as dry group. Density of all wood block was determined. Compression parallel to the grain and bending tests were carried out using Instron machine model 1186. Maximum stress (su), proportional stress (spl), Modulus of elasticity parallel to the grain (EL), modulus of rupture (MOR), apparent modulus of elasticity (MOE) and real modulus of elasticity (E1) were determined. Effect of tree spacing, geographic directions and tree height on the above mentioned properties was analyzed using random factorial design. Results showed that Paulownia wood having dry density of 0.26 g/cm3 and apparent density of 0.28 g/cm3 is a very light wood. Also, its high strength to weight ratio places it in special category material for making light and strong constructions. In addition, its strength properties increase with the height of the tree. Especially this effect is more distinct by decreasing tree spacing. On the other hand, less tree spacing produces high strength wood and more wood material, as well.

In order to assess the adaptation of Elaeagnus angustifolia L. and Fraxinus rotundifolia Mill afforestation around Tabriz international airport, the qualitative and quantitative characteristics of trees were measured in 96 experimental circular plots with a size of 300 m2. To study the edaphic effects of these species, nine samples were randomly collected from 0-10 cm and 10-20 cm depth of soil in Elaeagnus angustifolia L. and Fraxinus rotundifolia Mill stands and control plot (without afforestation). Results indicated that there was not significant difference between the diameter growth, height growth and mean basal area per hectare for Fraxinus rotundifolia Mill and Elaeagnus angustifolia L. In addition, Fraxinus rotundifolia Mill had more suitable qualitative status than Elaeagnus angustifolia L. In the analysis of the soil, it was revealed that these species increased soil EC in 10-20 cm depth, but without significant effect on T.N.V. and K values. Soil pH at the depth of 0-10 cm in Fraxinus rotundifolia Mill afforestation and control plot was higher than depth of 10-20 cm. Soil OC (Organic Carbon) and N percentage at the depth of 0-10 cm in Fraxinus rotundifolia Mill and Elaeagnus angustifolia L. afforestation was higher than depth of 10-20 cm, at probability level of 5 percent. These species reduced soil P content at the depths of 0-10 cm and 10-20 cm, at probability level of 1 percent. In other comparisons, there was not significant difference between means.

Classifying age classes in a large area using remotely sensed data has considerable significance for forest sustainable management. In this research, Landsat ETM+ data from Loveh forest, dating July 2002, were analyzed to investigate the potential of this sensor for age class mapping. We applied a systematic cluster sampling method to collect field data. We used 99 plots so that contained 32 plot. In stands with 25-45 years, 33 plots in stand with 5-25 years and 34 plots in stands with >45 years. The quality of the image was first evaluated for radiometric noises. Separability of three age classes 5-25, 25-45 and >45 years, using a supervised classification and four algorithm of maximum likelihood, minimum distance, parallel piped and linear discriminate analysis (Fisher). The results showed that maximum likelihood in three and two age classes with overall accuracy and kappa coefficient were (79% and 94%) and (0.68 and 0.86), respectively. Signature separability, producer and user accuracies showed the highest spectral similarity between 5-25 and >45 age classes. By merging the two classes, the overall accuracy and kappa coefficient became equal to 94% and 0.86, respectively. These results demonstrate that the reflectance values recorded by ETM+ sensor are related to forest stands. This information could also be used to estimate forest biomass and carbon content, identify locations within the stands that might require treatment and plan other management activities.

Current research was aimed to study the effect of soil different treatments on seed germination and seedling survival of Pinus brutia Ten. seedling in nursery of Koloudeh, located in Amol city. Seeds in plastic pots were sown at four different soil treatments including: (a) nursery soil (control), (b) control soil: cattle manure (5:1), (c) control soil: decomposited litter (5:1), (d) control soil: cattle manure: decomposited litter (5:1:1). The design was set up as completely randomized design (CsRD) with four replications. After recording data of germination, survival was studied in four months. The analysis of variance demonstrated that soil affected significantly all germination attributes, so that treatment (d) [control soil: cattle manure: decomposited litter (5:1:1)] had higher amount in all attributes (except mean germination time). The results showed that there was a significant correlation between germination attributes and soil type. Also a significant correlation was detected between seedlings survival and soil type, so that seedling survival was increased 25 percentages using organic matter (in treatment d). It is concluded from the results of this research that organic materials improve the physical and nutritious condition of the soil, which, consequently improves seed germination and seedling survival of pinus brutia. Thus, it is proposed to paya particular attention to the composition of the seedbed and nutritious elements of the soil-media in nursuries in order to enhance the qualitative and quantitative seedling production of this species.

The aim of this research was to identify the life form spectra in the Irano-Tourani region. Identifying these spectra can reveal the relevant life form species. By Comparison these spectra with other regions, life form spectra, the situation of this region among the other regions can be determined. It was carried out using Raunkiaer’s method to determine the life form spectra from Irano-Tourani region. It was applied using Detrended Correspondence Analysis (DCA) to identify variability among different vegetation life forms. The proportion of species in each life form class was analyzed and compared with Raunkiaer’s normal spectrum using a test. The result showed that in Irano-Tourani region the Hemicryptophytes and the Therophytes, were the main life form classes and usually the Phanerophytes were the least ones. Compared with life form spectra from other vegetation types, the Irano-Tourani region did not form a distinct group. The DCA indicated that the Mediterranean forests have more similar environmental conditions to the Irano-Tourani region.

Poplars are classified as fast-growing and slightly water tolerant species which will be weakened with decreased growth in extreme moisture or drought lands. The plantation of these species in agricultural lands and at the edge of rivers and water canals has currenthy an important role in both economical and social development of rural regions. The purpose of this study was to investigate and compare the effect of drought and hydromorphy stresses on three species of Poplars including Populus nigra 64.13, Populus deltoides 63.51 and Populus euramericana 476. For this purpose, the cuttings of the best clones of the mentioned species as wood production in Golestan province were planted in plastic pots. Then 30 seedlings of each species for each treatment were carried to the laboratory with the same conditions and were treated with water stress (drought and hydromorphy) and one control (150 milliliters irrigation every two days) as factorial experiment. Net photosynthesis rate (NPR) was measured daily by LCA-3 continuously till the seedlings were completely dead. The variance analysis and Duncan multiple comparison of data showed that water stress caused decreasing of NPR and viability percentage of the seedlings compared with control condition. Populus euramericana was more successful in hydromorphy and drought stresses in comparison with the other species, and also more resistance to hydromorphy than drought stress from the NPR and viability point of view. Whereas, Populus deltoides and Populus nigra had more resistance to drought stress than hydromorphy.

In order to determine the mechanical and optical properties of kraft liner paper made of the mixture of recovered OCC/ONP fibers with mixed local hardwoods virgin kraft pulp, OCC/ONP papers have been repulped in the common method of the paper recycling industry. The initial freeness value of each pulp was measured and they were separately refined to reach the suitable freeness value required to make kraft liner paper. The pulps have been mixed at (85, 10, 5), (80, 10, 10), (75 ,10, 15), (70, 10, 20), (70, 15, 15), (65, 15, 20), (50, 25, 25), (25, 50, 25) and (25, 25, 50) percentage rates of virgin kraft pulp, OCC and ONP papers, respectively. Handsheets were made, according to the related TAPPI standard test methods, from each mixture (treatment) and their mechanical and optical properties have been determined. The results were compared with those of control sample (100% virgin kraft pulp) using ANOVA technique. Normalization equation was calculated to determine the best treatment. The results have shown that with increasing the amount of OCC/ONP fibers in the mixture of pulps, tensile, tear and burst indices of the produced kraft liner paper decreased and brightness increased, in comparison to those of the control sample. According to the calculated normalization equation, the score of each treatment showed that 25/25 percent of OCC/ONP fibers (totally 50 percent) can be used in the mixture of local hardwood virgin kraft pulp to produce kraft liner paper with appropriate mechanical and optical properties.

Different ecologic factors influence on forming, development and sustaining of the plant communities, among which physiographic variables are the most important ones. The aim of this study was to identify forest types and effect of physiographical factors such as sea level height, slope and aspect of the site on quantitative characteristics of forest types in 2nd district of Vaz Forest with area of 847.5 ha in Chamestan city (Mazandaran Province). The field data were collected in 256 plots. Inventory grid was designed by a random-systematic method with dimension of 150×200 meter and sample circle plots with radius of 17.84 meter. In each sample, some of quantitative tree factors e.g., diameter breast height and control trees height were recorded. In order to recognize the type, total surface average equal to trees basal area in sample plot and Two Way Indicator Species Analysis (TWINSPAN) were used. Forest stands were grouped into seven forest types. In order to compare forest types and the role of physiographical factors on their quantitative characteristics, ANOVA and Duncan tests and Spearman correlation coefficient were used. The results showed that forest types are not only different in floristic characteristics but also in physiographic characteristics of sites. Other results also showed that the 6th forest type has minimum mean of basal area, volume and height of the control trees. It was also found that there were significant differences between mean of basal area and mean of volume, mean of regeneration and vegetation cover and mean of control trees height with geographical directions and sea level height, slope percent of the site and sea level height, respectively. It is notified the category of the sea level height (1200-1600 m) was recognized as an optimal condition for Beech stands (Fagus orientalis Lipsky.).