Journal of Wood and Forest Science and Technology
Year:2010 | Volume:17 | Issue:3|Papers Count:10

In order to evaluate capability of the Landsat-ETM and IRS-P6-LISS IV images for canopy cover mapping a case study was done on the forests of Javanroud in Kermanshah province. After evaluation of the geometric and radiometric quality of the data, the ETM+ images, the ETM+ images were geometrically corrected with GCPs and the images were registered with RMSE error 0.46 and 0.48 pixels, for X and Y, respectively. The COST method was used to atmospheric correction. 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 method with sample size of 60× 60m2. In each plot, the canopy of trees was measured in two directions and percentage of canopy cover was computed in hectare. The plots were classified to four classes (very thin, thin, semidense and dense) based on canopy cover.25% of sample plots from each class was selected as training area and the best spectral bands were selected using divergence separability index between classes. Regarding to area of canopy cover computing and in order to pixel size equalization of LISS-IV and ETM+ images, 6×6 pixel size of LISS-IV images were merged and their average value was used as a final value of merged pixel. Supervised classification was accomplished on the best and main bands. The accuracy assessment of generated map was evaluated using 75% of sample plots. The results showed that using the best selected LISS-IV bands could better classify 4 classes than other images by maximum likelihood algorithm with 64.54% overall accuracy and 0.43 kappa coefficient. In order to develop the results, the very thin class with thin class and semi-dense with dense classes were merged and a new classification was repeated. The minimum distance to mean classifier algorithm using the best selected LISS-IV bands showed the highest overall accuracy and kappa coefficient equal to 79% and 0.58, respectively. It is concluded that in such sparse forests, low canopy area of forest species as well as the soil reflectance as background leads to undesirable results.

In the past, forest road network designing was mainly done for its main goals management and exploitation. This study was performed to pay attention for multilateral goals of forest roads, especially its role in forest villages’ development, in Estakhr-Posht of Neka (6 villages) in series 2, section 6 of Neka-Zalem rood forest management plan. At first, constructed forest roads and suggested roads were calculated in 3 decades (1986, 1996, and 2006). Then, development situation and the benefits of studied villages services from implementation of the plan at each decades was determined by using statistical sources and related information to population and housing census, agriculture and complementally questionnaire for each one of villages (general, social, economic characteristics, services, facilities and available possibilities) on the basis of pre-eminent related to road construction.With doing attention to villages’ access to means of communication type of roads the advantage of profit rate of forest road was calculated. Data was processed with Excel software and then, the relation between accessing of forest roads donations and village development was analyzed by Pearson correlation test. The Result showed that Calculated correlation rate was equal to r=0.866 that alluding to direct and meaningful relation was between access to forest roads and village development. Finally this study indicated that the villages by accessing to forest roads for more years and means of communication in long time could be enjoyed possibilities, services and had best situation in respect of rural development.

Growth stresses develop in trees' trunks during formation and maturation of their growth rings. The asymmetric of growth stress field causes formation of abnormal wood called "reaction wood". This study has been conducted to characterize the effect of growth stresses on anatomical and physical properties of Fagus orientalis.Longitudinal growth stress was measured at 8 equidistant points on circumference, at breast height of 19 standing Beech trees in parcels 117 and 223/220 at Kheyroudkenar Research Forest. Using displacement gauge, longitudinal Point with greatest stress history on each sample tree was marked, and then trees were cut down to collect test materials for anatomical and physical properties. On cross-section of each sample bolt segment of harvested trees, area with greatest stress and its opposite were identified to cut out specimens. Results of investigations have shown that in the area with greatest values of longitudinal stress, tension wood has formed. In this area comparing with opposite wood of cross-section, number of vessels, diameter of vessels' lumen and typical fiber diameter were lower, but length and wall thickness of fibers and average percent of fiber content, shrinkage and swelling rates were higher. There were no significance statistical difference between moisture content and basic specific gravity in wood of both areas.

Plantation of fast-growing species such as Poplar is one of the important methods for wood production in the countries with low natural forest areas.Physiological differences of Populus deltoides clones planted through three decades in Shast Kalate research forest are unknown. Peroxidase enzyme in this research was used for clone separation as a biochemical marker that is sensitive to environmental alteration especially temperature and its direct participation in lignification process. Sampling was done from one year old seedlings of five clones and quantitative and qualitative activities of peroxidase during five months (September through May) were measured using Worthington and PAGE methods, respectively. The results showed that peroxidase quantitative activity and isoenzyme pattern of clones were different among the months which indicated the role of this enzyme in cold hardiness and lignification of the clones.

Deinkability of old newspaper was investigated using cellulase at different concentrations and treatment times. The results of optical properties of the made papers indicated that by increasing the enzyme concentration to 0.05 percent the brightness was increased to 47.5% ISO and yellowness decreased to 11.03% ISO.While at higher charges than 0.05 percent, brightness value the was decreased and yellowness increased. Opacity of paper was improved to 99.3% ISO by increasing the enzyme charge to 0.1% but it was reduced at higher levels than 0.1%. It was observed that enhancing of treatment time to 15 minutes and also using one-stage washing resulted in the highest brightness of 47.5% ISO, the lowest yellowness of 11.03% ISO and the opacity of 97.4% ISO. Maximum opacity was observed at treatment time of 10 minutes. With regard to the results from paper provided with enzymatic deinking of old newspaper, we could produce the papers with desirable brightness and low yellowness using optimum charge of 0.05% cellulase and treatment time of 15 minutes along with one-stage washing. We could also obtain higher opacity values using 0.1 percent enzyme or 10 minutes treatment time.

In this research, the influence of red heartwood formation in Iranian Beech (Fagus orientalis L.) on its drying behavior was studied. Radial variation (from pith to bark) in specific gravity, green moisture content, drying rate, transverse shrinkage and casehardening in a Beech log containing red heartwood was investigated. All samples were dried in an experimental kiln under a constant temperature of 60oC and relative humidity of 40% to the final moisture content of about 8%. The results showed that the wood containing red heartwood had greater specific gravity and lower green moisture content than normal wood. In addition, it was revealed that the red heartwood formation in Beech decreased the drying rate and increased shrinkage and casehardening. The microscopic studies indicated that the tylose presents in the vessel cavities of red heartwood Beech. Thus, the different drying behavior of Beech red heartwood can be attributed to the tylose in the vessel cavities.

Increasing of wood demand is currently one of the most important problems in our society. Different clones of Populus nigra from salicacea as a native fast growing species have a good potential for planting in wide scale. But because of the ecological differences in the field, especially. Temperature alterations, segregation of the cold resistant clones in relation to in seedling stage establishment is very important. Peroxidase enzyme as one of the most sensitive physiological factors to environmental stresses, especially low temperature was used to compare the ability of cold resistance of five clones of this species.Quantitative and qualitative activities of this biochemical marker (POD) were studied during five months from September till May. The result indicated that P.nigra62.231 and 64.13 clones had the best ability of early autumn cold resistance and P. nigra 56.52 clone had the best ability of late spring cold resistance. Also, P. nigra 62.171 and 64.13 clones the best winter cold resistance.

In this study Beech wood (Fagus orientalis Lipsky) samples with dimentions of 150´75´5 mm were prepared and subjected to a variety of artificial weathering conditions in an Atlas Xenon Test Beta LM Weatherometer to UV radiation (300 nm) and visible light (750 nm) and water spray in different times (50, 150 and 300 h). Then wood surface was analyzed for chemical and structural changes using Fourier Transform Infrared (FTIR) spectroscopy and Scanning Electron Microscopy (SEM), respectively. Results showed that weathering process affected the functional groups on the wood surface. Full weathering (light and water) damaged the surface polymer structure and caused chemical and physical changes in wood. The greatest changes occurred in the functional groups and aromatic structure of lignin. With increasing of weathering time, the absorption intensity of c=o loonds increased at 1730-1740 cm-1 and aromatic skeletal vibration in intensity 1514 cm-1 decreased. By the effect of UV radiation, choromophoric groups were produced in lignin. Photochemical cleavage of C-C bonds adjacent to carbonyl groups made the chemical compounds smaller and water-soluble. The SEM results showed that the surface of wood exposed to weathering undergoes distinct physical changes and the surface degradation appears to be directly proportional to the time of exposure to the weathering conditions. However, trace changes were observed in samples weathered for 50h.

The purpose of this study was to evaluate the dimensional stability and mechanical properties of three-layer particleboard produced from linear chain carboxylic acid anhydride modified bagasse particles. Modification was performed via esterification of bagasse using acetic anhydride without using any catalyst and solvent at 120oC for 240 min at lab scale. Bagasse with two particle sizes including fine (0.2-0.4 mm) and coarse (0.8-1.2 mm) were modified. Different weight percent gains (WPGs) were obtained with different sizes and reagents.Acetylated and unmodified bagasse particles were pressed into three-layer particleboards using phenol formaldehyde (resole type). The physical and mechanical properties of the boards were tested. The particleboards made from esterified bagasse particles were more dimensionally stable (about 87%) than control boards made from untreated bagasse. But the mechanical and physical properties of the modified boards were lower than control board.

Acquiring up-to-date information about stands is necessary for scientific management and planning of forest. Remote sensing by its great capabilities in this way can be very useful. This study was done to investigate the capability of satellite data for gathering information about Beech diameter specification.21 plots of one hectare dimension were selected at experimental forest of Kheyroud in Noshahr. In each plot, diameters of all trees above 12.5 cm were measured and recorded. Then geographic specifications of centennial portion and four corners of each plot were recorded and their digital map was prepared. Geometric correction was performed up to orthorectification level with affine transformation and resampling of nearest neighbour with less than 0.6 pixel error. For surveying of synthetic bands and various indices, Principle component analysis, Ratio and Fusion were used. Then digital numbers matching with plots from principle and synthetic bands were extracted and used in regression analysis test. Results showed that maximum correlation of diameter was with G/R, GRVI, [(G+NIR) -R] / (G+R+NIR), R+G+NIR with correlation coefficients of -69%, -67%, -54% and -53%, respectively. After extraction of correlation coefficients, equations of relationship between diameter and digital numbers of images were produced. Results of this study supported the hypothesis of possibility of predicting diameter of Beech stands using satellite images.