Journal of Wood and Forest Science and Technology
Year:2012 | Volume:19 | Issue:4|Papers Count:15

The aim of this study was to recognize plant communities of Box tree (Buxus hyrcana Pojark.) stands in the Khybus protected area, located in the middle part of Hyrcanian forests (north of Iran). Vegetation releves, 64 numbers, were made at peak vegetation cover during last summer by systematic-selective method in 200 and 400 meter grid dimensions by consideration indicator stands concept. By using Braun-Blanquet tabular method, six distinct plant communities including three associations: Rusco hyrcani-Fagetum orientalis, Buxus Hyrcani-Fagetum orientalis and Tilia sp.-Buxetum hyrcana with three subasociations: Rusco hyrcani- Fagetum orientalis Lauroceraetosum officinalis, Buxus Hyrcani-Fagetum orientalis parrotioetosum persica and Buxus Hyrcani-Fagetum orientalis aceretosum velutinum were determined. By using two way indicator species analysis, TWINSPAN, six plant communities were recognized. Braun-Blanquet tabular method and TWINSPAN fitness were estimated as 98.4% based on similar membership of relves in each plant community. Moreover, plant communities based on two first DCA axes, which represent 33% of total variances in whole of floristic data, revealed that each plant community had its own range and rather clear bordeline. Totally, results of this study not only describe plant communities of Khybus protected area as a climax model of Hyrcanian mountainous forests for the first time but also confirm that subjective Braun-Blanquet method, despite the development of numerical methods in multivariate classification of vegetation, can be used as an efficient method of separation and classification of forest sites.

In this study, physical, chemical, and papermaking properties of sweep plant stalk (sorghum bicolor) prepared from northern and northwestern areas of Iran was studied to evaluate its papermaking potential. The prepared stalks were cut into three parts in length and then the bark and core of each sample were seperated. Morphological characteristics, papermaking factors, and chemical composition including amount of lignin, cellulose, extractives and ash of each sample were determined according to TAPPI standards. The results of papermaking factors of this plant’s stalk fibers (that are related to fiber length and wall thickness) indicated that it had potential of producing paper with higher strength properties compared to common raw materials and even local hardwoods. So, interesting results of chemical analysis of this plant’s stalk samples showed higher value of cellulose and lower amount of lignin in comparison with woody and nonwoody plants that is considered as one of the most important affirmative factors (easy and cheap lignin removal process) in papermaking raw materials. Results of all physical and chemical assessments showed better characteristics of the bark comparing to the core. Of course, considering the low ratio of core to bark (contrary to other nonwoody plants) it is concluded that pulp produced from whole stalk have no significant differences with pulp prepared from bark. Sweep plant of northern Iran has longer fiber with more cellulose content and less extractives in comparison with northwestern type. Thus, it is suggested to mill owners to be used as a suitable raw material in this industry.

Possibility of estimation of quantitative forest characteristics without field survey is a new idea for forest biometry. This investigation was conducted to evaluate possibility of spatial estimation of two main quantitative forest characteristics (trees number in hectare and mean diameter) using terrain analysis and linear regression models in the district 1 of Dr. Bahramnia (Shastkolate) forestry plan, Golestan Province. A digital elevation model (DEM) with 10×10 meter resolution was produced by contours interpolation of 1:25000 scale maps. The primary topographic attributes maps (slope, aspect, elevation from sea level, shaded relief, profile curvature, plan curvature and tangential curvature) and secondary attributes maps (wetness index and solar radiation) were derived from DEM using terrain analysis software. Field inventory data from second revision of Shastkolate forestry plan, district I (429 plots) were used as original data for forest quantitative characteristics. Information of topographic maps in plot location was derived. Then relationship between the forest characteristics and terrain attributes was analyzed and modeled using multiple linear regression models by stepwise approach. The developed models were validated using test data (85 plots). Adjusted R2 and root mean square error (RMSE) were determined to validate accuracy of prediction. Result of study showed that elevation from sea level, annual potential of solar radiation, slope and aspect were the most significant terrain attributes determined the spatial distribution of forest quantities characteristics. Results also showed that forest characteristics could be predicted about 40% to 47% of variation by these linear models. These models can be used for estimation of quantitative characteristics for adjacent forests with similar conditions (same management and morphology) using DEM without measurement or sampling. Finally, use of terrain analysis was emphasized for preliminary recognition of forest quantity characteristics.

This paper aims to study the plant biodiversity in a natural forest and the adjacent 20-years-old plantations of Alder (Alnus subcordata C.A. Mey.), Velvet Maple (Acer velutinum Boiss.), Chestnut-leaved Oak (Quercus castaneifiolia (C.A. Mey.) and Cypress (Cupressus sempervirens var. horizontalis) in Darabkola, Mazandaran province, north of Iran. For this purpose, one sample plot, each 1 ha; was selected in every plantation as well as in the natural stand. In each sample plot 10 microsample plots, each 100 m2; were selected random-systematically. All of the plants were determined in the sample plots and their coverage percent were estimated in four seasons. Moreover, various parameters of the stands and soil properties were measured in each sample plot. For determination of plant species diversity in these plots, Shanonn’s and Simpson’s indices were used, while for determination of species richness and equitability, Margalef’s and Heip’s indices were applied. The results showed that Alder plantation and natural forest had the highest values, whereas Cypress plantation had the lowest value for species diversity. The highest Species diversity in other plantations was for Velvet Maple, Chestnut-leaved Oak and Cypress, respectively. The analysis of PCA showed that seasonal differences of species diversity on our studied plots were affected by the crown canopy of plants in the upper-story, and the under-story crown canopy of plants with the number and density of plant species in the under-story as well as by environmental parameters including rainfall, temperature and relative light intensity.

In this article the most important indices of diversity and richness of woody species, in relation to three physiographical factors, including altitude, aspect and slope have been discussed. For this purpose, ecological characteristics in 330 circular 500 m2 plots, were studied by systematic random method. Vertical distance of sampling units was 100 m above sea level. Sampling in 4 different areas, in range of 800-2400 m elevation was performed. Map Position plots was produced by the GIS and GPS systems. Results showed that statistically difference between classes of each topographical factor, in relation to the indices of diversity and species richness was significant. This study in relation to Simpson indices in altitude factor, showed that the difference between first class (800-1300 m) and third class (up to 1800 m) is exceptionally significant, In the other indices, difference of first class to third class and second to third, was significant. In other hand, diversity and richness indices of class in high altitude were more than other classes. Average of all indices in the northern aspect was higher than south and flat areas. Results of Shannon and Simpson diversity indices to slope factor, showed that first class slope (0-10%) compared to third (30-60%) and fourth class (up to 60%), and second class slope (10-30%) compared to fourth class slope, were statistically significant. Moreover, average species richness indexes in low-slope land (0-10%), compared to areas with slope over 30% (third and fourth classes), were higher. Therefore, it can be seen that the species diversity indices, in areas of low slope are higher than high slope areas, and about the species richness indices, are opposed to this case. This is due to that diversity indices values are decreased by a decrease in the canopy in studied areas of low slope. Due to the relative increase of the presence of woody species in the low slope areas, the species richness indices have been increased to some extent.

Quercus castaneifolia is one of the most important industrial trees in northern forests of Iran. Its habitats have been damaged because of severe utilization. Leaf and fruits morphology was assessed in five Oak stands located in Mazandaran forests, north of Iran. The populations distribute from 100 to 1100 meter altitude above see level in two region named Neka and Nour, with 200 kilometer interval. The pattern of leaf and fruit morphological variation was evaluated for evidence of genetic variation in these five populations. Principal component analysis was applied to data set of leaf and fruit characters from five populations to describe between and within genetic variation of Oak population. The results showed that difference between five populations was significant in more leaf and in fruit traits. According to principal component analysis, among the 31 fruits and leaf traits, leaf area, maximum width of leaf laminate, number of teeth on the right, pair of main nervure, petiole length, leaf maximum total length, dry and wet weight of fruit, large diameter of fruit, special shaped seed, diameter and height of corn have had the most important role in defining and creating the main components of variance, and were found also the lowest plasticity. Results of morphological characters showed that the variation between individuals of population located in 400 to 600 meter altitude above see level was higher than the variation of individuals in lower altitude populations. Those of two mentioned population were located near the some villages.

The purpose of this study was to compare the performance of cellulosic pad made of kraft hand sheet papers and commercial cellulosic pads (CELdek 50×90 and CELdek 70×90). Hand sheet papers were made by the use of a large hand sheet maker at available at pulp and paper laboratory of Wood and Paper Science and Technology department at the University of Tehran and then corrugated with B flute size in Pars carton factory. After cutting, corrugated papers were cross-laminated by kraft adhesive and with 90 degree flute angle. Then, pads were soaked in NS-88 resin and dried at 35±2 oC. Cooling efficiency and water consumption of experiments were measured as a function of air velocity. Cellulosic pads were tested in a wind tunnel at three different levels of air velocity (1.8, 2.25 and 2.67 ms-1). The results showed that cellulosic pads made of kraft hand sheet papers had the highest efficiency compared to the commercial cellulosic pads (CELdek 50×90 and CELdek 70×90). It has also been found that by increasing the air velocity, the cooling efficiency decreased and water consumption increased.

Twin-screw extruder has been attractive with many efficient benefits as one of developing pulping technology from non-wood feedstocks in recent decades. Extrusion pulping is a chemi-mechanical pulping method in which fibers are processed by means of compression and shear forces. In this research, application of this technology was introduced in pulp and paper industries and the extrusion pulping of rice stalk was investigated. Extrusion pulping of rice stalk was conducted following a central composite design using a two-level factorial plan involving three process variables (pretreatment NaOH concentration: 0.4, 0.8 and 1.2%, extrusion temperature: 40, 60 and 80 oC, extruder rotational speed: 55, 70 and 85 rpm). Responses of pulp properties to the process variables were analyzed using statistical software (MINITAB 15). As the results show, a more content of initial ash of rice stalk was remained in the obtained pulp. Also, because of high freeness of obtained pulps, it is necessary to retransfer the obtained pulp from extruder or refine it for fluting paper and linerboard production. Moreover, analysis of the results reveales that this process can be used to obtain a pulp with low kappa number under a relatively long pretreatment time, high NaOH concentration, high extrusion temperature and moderate extruder rotational speed.

In this paper deinkability of office waste deinked pulp by commercial cellulase from Aspergillus niger fungus and chemical method using flotation process was compared. Progress in appearance properties of deinked papers was studied by reverse power fit equations. The results showed that the top side and wire side of the deinked pulp handsheets had significant difference in dirt count and area of ink particles. Maximum decrease in ink count and ink area, occurred in the first 10 min of flotation, the rate of deinking was reduced by increasing flotation time. Handsheet brightness was initially increased by increasing flotation time and then reduced by further flotation.

Structure study of the forest is one of the important subjects of silviculture close to nature. Recognition of Juniper forests as the main structure of natural forest ecosystems, is necessary for the degradation process. In this research, in order to study the structure of natural Juniper stand in protected forest, 49.53 ha of Juniper stand was selected (Khalkhal forests) and 100% inventory was applied. Forest stand characteristics including species mixture, number per hectare, diameter at breast height, total height and crown diameter were measured and analyzed. Results show that the stand is basically uneven-aged and Juniperus excelsa is the dominant species. The mean forest canopy, mean basal area and mean number per hectare are 42.85%, 4.68 m2 and 592, respectively. The stem number frequency of tree in diameter at breast height shows an uneven-aged pattern. Totally, the study of stand in terms of structural is a mixed, unevenaged and open canopy cover stand.

This study was aimed to investigate the effect of different charges of sodium silicate on chemical deinking of old newspaper. Chemical deinking process was accomplished with 1% hydrogen peroxide, 1% sodium hydroxide, 0.3% DTPA and 0.15% surface active agent at different charges of 0, 1, 2 and 3% sodium silicate on the basis of oven dry waste paper. The results of the optical properties of produced paper showed that the brightness of paper improved (50.9%) and the yellowness decreased (11.33%) with increasing of sodium silicate charge to 2%. Increasing of sodium silicate use from 0.3% did not indicate significant effect on opacity values. The highest opacity (98.8%) was achieved by 1% sodium silicate. The results of the physical properties indicated that increasing of sodium silicate use up to 2% resulted the paper with the highest bulk (2.75 cm3/g). Totally, the consequences of this research in relation to chemical deinking of old newspaper at different charges of sodium silicate showed that use of 2% sodium silicate would lead to produce the paper with higher brightness, caliper and bulk along with desirable opacity.