Journal of Wood and Forest Science and Technology
Year:2012 | Volume:19 | Issue:1|Papers Count:15

Forests area of Iran in comparison with the world is very low and this low area is in demolition threat always. Hence, the remainder of these forests should be managed based on ecological capability evaluation. With regard to importance of subject, in this study, ecological capability for forestry in the Babolrood watershed, Mazandaran province, was evaluated and for this purpose, the Analytical Hierarchy Process and Geographic Information System (GIS) were used. Respectively in first, Criteria and indicators were selected and relative weights were assigned using Delphi method and expert's judgment. Then, indicators were mapped in GIS environment. In final, ecological capability map for forestry was created using GIS-based Weighted Linear Combination technique. Results showed that 4072.5 hectare for forestry has one class capability and respectively 25667.2, 8801.5, 1482.9 and 103.1 hectare have the two, three, four and five classes’ capability. 11597 hectare of study area has got no capability for forestry.

Forest roads are constructed to access forest interior, wood extraction, conservation, afforestation and recreation. In forest road construction project, the trees and vegetation cover are removed and the soil structures are damaged. So, this causes to increase sediment production in forest roads. Increasing of the yield of sediment to river can damage water quality and aquatic ecosystem. Nowadays, there are different models for prediction of sediment yield and this can be helpful for researchers to predict amount of sediment production in forest roads. In this research, SEDMODL was used to estimate mean of annual production of sediment in forest roads. A road with a length of 2260 meter which is located in compartments of 26, 27 and 32 of Darabkola forests was selected. Then, the road length, road width, production rate of sediment with considering geology condition, road surface factor, traffic factor, longitudinal slope, rainfall and sediment delivery factor were calculated using GIS maps, forest management plan handbook and field survey. Results showed that the production rate of sediment in roads was 77.514 ton per year and of this value, 13.175 ton per year is imported to stream canals and rivers. Besides, the slope, distance of road to stream canals and cut slope height were the most important factors in sediment production and delivery to stream canals.

In order to evaluate capability of the IRS-P6- LISS-III and LISS IV images for canopy cover mapping a case study was done on forests of Javanroud in Kermanshah province. The quality of images was evaluated for radiometric and geometric errors. No considerable radiometric distortion was found in the images. The LISS-III images were geometrically corrected with image to image method using 18 ground control points. The RMSE was 0.43 and 0.36 pixels, towards X and Y, respectively. Several image enhancements such as spectral rationing, PCA transformation and vegetation indices were performed. To reduce the effect of soil reflectance, suitable vegetation indices were prepared using soil line parameters. A ground truth map was generated through random systematic sampling with sample size 60 m×60 m. The canopy cover percent of trees was measured in two directions and percentage of canopy cover was computed in each plot. Based on canopy cover the plots were classified into four classes (very thin, thin, semi-dense and dense). Twenty five of sample plots from each class were selected as training area and the best spectral bands were selected using divergence separability index. Regarding canopy cover area and in order to equalize the pixel size of LISS-IV and LISS-III images, pixel sizes of LISS-IV images were aggregated in 5×5 pixels. A supervised classification was accomplished on the best and main bands. The accuracy assessment of generated map was evaluated using 75% of the sample plots. The results showed that using the LISS-III image data within 4 density classes the highest overall accuracy and kappa coefficient were equal to 65.77% and 0.45 and using aggregated LISS-IV images they were 63.27% and 0.41 respectively. These results showed that using the best selected bands by maximum likelihood algorithm could better map forest canopy cover classes. In order to improve the results, the very thin class with thin class and semi-dense with dense classes were merged together respectively and classification was again repeated. In this case, the maximum likelihood classifier algorithm using the best selected LISS-III bands showed the highest overall accuracy and kappa coefficient of 78.68% and 0.57 respectively and the minimum distance to mean classifier algorithm using the best selected equalization of LISS-IV bands showed the highest overall accuracy and kappa coefficient of 78% and 0.57 respectively. Conclusion to be made from this investigation is that in such sparse forests, low canopy area of forest species as well as the soil reflectance as background cause low performance of classification.

The effect of pressure screening fractionation of OCC pulp on several conventional pulp fiber structural defects such as curl and kink indices evaluated in this research. Aperture velocity and volumetric reject ratio were considered as variable parameters of screening operation and eight trials totally conducted in this work. Curl and kink indices and total kink angle of feed, accept and reject ratio of pulp fiber determined using fiber quality analyzer (FQA). The results of this study showed that pressure screening increased pulp fiber structural defects. Also, it was found that curl and kink indices and total kink angel of pulp fiber increased as aperture velocity raised but, change in volumetric reject ration didn’t considerably affect structural indices. Refining process of long fiber fraction had an affirmative role on decreasing of fiber structural defects. According to the results of previous works that introduced refining as a suitable device to pulp fiber fibrillation of OCC pulp and findings of this study, refining could be strongly recommended for OCC pulp improvement.

The main aim of this study was to investigate forest cover changes in Ilam watershed from 1965 to 2006. The forest cover map was produced using a digital aerial photo mosaic, scale 1:20000 for 1965. The IRS-LISS III images were also employed to generate the map in 2006. After radiometric and geometric corrections, different image processing techniques, such as band rationing, tasseled cap transformation and principal components analysis were applied on the imagery to be entered in image classification process. The optimum bands set have been selected; using OIF (optimum indexing factor). Image classification was done using supervised rule (Maximum Likelihood and Minimum Distance) once for the 6 land use/cover classes i.e. forest, rangeland, agriculture, gardens, bare land and settlements and then for forest and non-forest classes. Accuracy assessment of forest-non forest mapping indicates that the highest overall accuracy is belonged to employ ML classifier (83% the overall and 78% the Kappa). Comparing the results in the period indicates that forest area in the region has been reduced about 16000 ha in a 42 years.

In order to investigate the potential of two agricultural residues (cotton and corn stalks), laboratory MDF boards were produced using fibers generated applying ten minutes steaming at 175oC, defibrated with 25 centimeters single disc refiner. Three press temperatures (170, 180 and 190oC) were used. For board pressing. Boards after conditioning at 65% RH and 21oC and then test samples were prepared according to relevant EN standard. All tests were performed according to relevant EN standard methods and then analyzed. The results indicate that the strength (MOR and MOE) of boards produced from corn stalks is almost 25% higher than those from cotton stalks. However no significant difference was observed for internal bonds of boards. Thickness swelling of MDF boards from corn stalks was lower than cotton stalks. Comparing the results with the strength of boards produced from beech wood showed the similarity between corn stalks and beech wood, but the strength of MDF boards from cotton stalks was lower than those produced from beech wood. Our results fulfill the minimum EN requirement.

The influence of pulping temperature, time and alkali charge on residual lignin and viscosity of soda pulp produced from bagasse was investigated. Two pulping temperatures (175oC and 185oC), three pulping times (20, 30 and 40 minutes) and three alkali charges (14, 16, 18% NaOH, OD basis) were used. Factorial experiment based on randomized block design was applied to analyze the effect of pulping variables on total yield, accepted yield, pentosans content, viscosity and kappa number of the pulps. The results showed that higher intensity of pulping reduced both total yield and kappa number. At 175oC pulping temperature, increasing pulping time and alkali charge reduced pentosans content and viscosity, but the reduction of these properties was severe at pulping temperature of 185oC. Higher pulping temperature and time reduced pH of black liquor, which indicates consumption of more alkali during pulping. At milder condition of pulping higher pulp viscosity and pentosans were measured and at severe pulping condition, both properties were reduced which indicates the degradation of carbohydrates especially cellulose. The measured viscosity of pulps produced at 175oC and 185oC were 11.73 and 11.34 cps, respectively, and the related values for pulps produced at 20, 30 and 40 minutes pulping time were respectively 11.78, 11.57 and 11.24 cps. The results showed that pulping time and temperature are the most influential factors on carbohydrate degradation and the influence of alkali charge is not as severe as pulping time and temperature.

Three natural lowland habitats of Zelkova carpinifolia in three provinces of North of Iran (Gilan, Mazandaran and Golestan) evaluated for identifying the best morphological characters in genetic diversity investigation. 16 morphological traits of 5 leaves, which were selected randomisly of 10 trees in each habitat, were examined. The number of leaf venation, the leaf length and leaf maximum width exhibited the highest variance and the least plasticity among 16 evaluated traits and have the most important role in individuals grouping. Nested ANOVAs results show that trees differentiation variance has the highest value relative to population differentiation variance. Because of the least effective of environmental conditions, these traits suggested for genetic diversity investigation.

In this study, layering technique effect of particleboard with poplar particles on physical and mechanical properties was evaluated. To attain this purpose, surface layer particles type (poplar and industrial), resin content (8 and 10 percent) and press time (4 and 5 minutes) were selected as variable factors. The properties that were investigated consisted of Modulus of rapture, Modulus of elasticity, Shear strength and Thickness swelling in 24 hours. Results showed that using poplar particles in surface of panels significantly increased physical and mechanical properties of boards. The press time had the most particular effect on shear strength. With increasing press time, this strength was increased. In other hand, resin amount increasing in surface layer from 8 to 10 percent improved all of the properties. Finally, to obtain high physical and mechanical properties and efficiency, application of poplar particles in surface layers, using of 8% resin content and 4 minutes for press time was found as the best condition.

The gypsy moth, Lymantria dispar (L.), is one of the most important pests of forest trees throughout the world. Larval herbivory can result in leaf area reductions, leaves abscission, and eventually, yield quality and quantity losses. The objective of this research was to determine the effects of oviposition height and host tree species on some biological parameters of gypsy moth, including egg clutch size, egg hatching percent, larval body length and mortality percent of first instars. Sampling was carried out in Daland forest park (Infestation foci in Golestan province) during 2008 and 2009. Samples were taken on five oviposition heights (0.5, 1, 1.5, 2, and 2.5 m) on trunk of four common host species including, Zelkova carpinifolia, Parrottia persica, Quecrus castanifolia and Carpinus carpinifolia. A factorial experiment in a randomized design was used to analyze the data and means were compared using Duncan’s multiple range test. Results showed that the oviposition heights significantly affected pest biological parameters, but the effects of host tree species and interacting effects were not significant. The highest survival percent, egg clutch size and body length was observed at oviposition height of 0.5 m on the Parrottia persica species, and the most larval mortality of first instars was recorded at oviposition height of 2.5 m on the Quecrus castanifolia species.

Using pheromone traps is one of the suitable methods for monitoring and control of forest pests. The objective of this research was to determine the effects of atmospheric conditions and daily times on pheromone traps efficiency of the gypsy moth, Lymantria dispar (L.). Sampling was carried out in Daland forest park during 2008. Samples were taken on three atmospheric conditions (sunny, cloudy and rainy) and daily times (07:00 AM, 08:00 PM and 01:00 PM). A factorial experiment in a randomized design was used to analyze the data and means were compared using Duncan’s multiple range test. Eight white traps were placed on trees at distance of 100-150 m from each other at 1.5 m height in each site. Results showed that atmospheric conditions and daily times of day had significant (P<0.001) effects on number of males capture in pheromone traps. The interaction of daily times and atmospheric conditions were also significant. Maximum captures of male moths were observed at 07:00 AM, and sunny conditions. Also, minimum captures occurred in 08:00 PM and rainy conditions.

Mixed office waste deinking by conventional chemical process, other than having higher chemical consumption and considerable emission of environmental pollutions, has relatively lower deinking efficiency. On the other hand, enzymatic deinking increases deinking efficiency even at reduced environmental pollutions, but it may reduce the strength properties of deinked pulp. At present paper, the physical and strength properties of mixed office waste enzymatic deinked pulps, selected from superior enzymatic treatments in terms of deinking efficiency using commercial cellulase enzyme from Aspergillus niger, were compared with the selected superior samples of chemical deinking treatments and the reference sample. The results showed that, the hand sheets of enzymatic deinked pulps, in comparison with chemical deinking, had lower caliper and bulk but without having significant differences with chemically deinked pulps in terms of the strength properties. As a result, because of its better deinking efficiency and also acceptable physical and strength properties, enzymatic deinking was recommended, as a proper substitute of conventional chemical deinking, for deinking of mixed office waste papers.