Journal of Wood and Forest Science and Technology
Year:2012 | Volume:19 | Issue:3|Papers Count:12

In order to better identify the structure of Pistacia atlantica stands in Zagros forests, diameter structure was analyzed using geostatistics technique in a pure stand of Pistacia atlantica. For this purpose all the trees in the stand were mapped and their stem diameters were measured at breast height. Diameter distribution showed that more than 90% of trees belong to diameter classes 25 to 80 cm. Furthermore, no tree was observed with the DBH<16 cm because of unsuccessful establishment of regeneration during the last decades. An omnidirectional variogram was used to variography because of the no sign of anisotropy. An exponential model was fitted to the experimental variogram and then estimations were mad using ordinary kriging. Ripley’s K function was used to survey trees spatial pattern. Results indicated an average spatial structure for DBH in this stand with lag distance 15 m and effective range 85.2 m. The spatial pattern of trees was aggregated confirming the positive correlation between trees. It implied that unsuccessful establishment of regeneration and the quality of seedbed resulted in the existing of this spatial structure. Because on one hand there was no tree with DBH<16 cm and on the other hand trees with DBH<40 cm were just observed in rocky places between stones.

In order to investigate on qualitative and quantities characteristics of Juniper stands, a 613 ha case study area was chosen in the Aminabad of Firouzkoh. In this study, the stratified sampling method was used and the study area was stratified to homogenous regions based on slope, aspect and geological unites in GIS environment. By combining the slope and aspect maps, we made the landform unit map. Landform unit map and geology map were then overlaid to produce the homogenous unit map. Then 42 units randomly selected for forest inventory and in each unit randomly one point specified as centre of cluster. After visiting the study area, the Juniper coverage were observed only in 20 clusters and others clusters were bare and without Juniper coverage. In conclusion, in the 20 clusters containing the Juniper trees, center and other 4 points around them in main geographical aspect in distance about 50 meters from centre of cluster have considered as plot with 1000 m2 area. In each plot, tree height, diameter at breast height, coppice or seeding crop, sexuality, crown canopy area, slope percentage and geographical aspect were measured and computed for each cluster in terms of hectare. Relation analysis by ANOVA test was used for differentiation test between clusters based on qualitative and quantities characteristics of Juniper stands. The results shown that in the study area the juniper stands are as irregular even aged stands with the left skew ness in point of distribution of trees in diameter class. Results showed an intense decreasing in 30 cm diameter class regenerations due to human activities and close to road and village of Aminabad. In addition, result of canopy cover density in the study area showed that the Juniper stand of Aminabad is thinner in comparison with other studied Juniper stands. The mean, maximum and minimum of tree density in each plot was 31.5, 170 and 0 in hectare respectively. The mean, maximum and minimum tree height in the study area was computed 4.9, 10 and 2 meter, respectively. The maximum measured DBH of juniper trees was 62 centimeters. Also the mean, maximum and minimum canopy cover of study were 750, 2470 and 0 m2, respectively. According to qualification, the percent of seeding crop trees in the whole stand is more than coppice trees and between male, female and ambisexual, we can see females are more than the other kinds.

The pulp strength properties of old corrugated containers (OCC) are reduced as a result of recycling process. So at present paper, improvement of OCC pulp properties was investigated through refining and also using cationic starch and imported unbleached softwood kraft pulp (USKP). In addition to studying the effects of each of above mentioned parameters, the effects of combined treatment of refining+ cationic starch, refining+USKP, and cationic starch+USKP were also investigated. Cationic starch at 3 dosing levels (0.5, 1.0 and 1.5%) and USKP at 3 dosing levels (5, 10 and 15%) were used in admixture with refined and unrefined OCC pulps. The results have shown that treatments such as refining, cationic starch, USKP, and cationic starch+USKP significantly improved the OCC strength properties. The highest strengths were obtained from treatment of 1% cationic starch+15% USKP, which in comparison with reference sample; about 40% increase in burst and tensile strength, and 30% increase in tear strength were occurred. Air resistant, in treatment where 1.5% cationic starch was used in refined pulp, was increased 45% as compared with the reference sample. The results showed that the optimum treatment, in terms of obtaining highest improvement in OCC pulp properties, was a combined treatment of refining+cationic starch+USKP. However, depending on the required end use quality, OCC pulp can be improved by using refining treatment with or without using different dosages of cationic starch and USKP.

Investigation on site demands of forest species such as physiographical factors and soil characteristic are necessary for improvement, reclamation and conservation of plant cover. Amygdalus scoparia Spach. is one of the most important forest species in Markazi Province with edible use, industrial, environmental and protective values. In this research, firstly, all of the regions were surveyed and with regard to variables such as aspect, altitude and slope, sampling performed by 61 plots and GPS device in four areas of Jalayer Saveh, Nimvar Mahalat, Jaftan Tafresh and Sarabadn Tafresh. In each sample plot, some physical and chemical soil properties (K, Caco3, C, N, clay, silt, sand, EC, pH and P) and as well as quantitative measurement of species growth such as (tree density in hectare, crown diameter, height, basal area each tree, basal area in hectare and regeneration) were conducted and then the data were analyzed using SPSS and PC-ORD. The results of One Way ANOVA showed that of altitude, slope, Caco3, EC, P in Nimvar Mahalat, sand and basal area in hectare in Jalayer Saveh and Sarabadan Tafresh, tree density in hectare in Sarabadan Tafresh had the highest amount. The lowest altitude and silt is in Jalayer Saveh. The results Principal Component Analysis (PCA) showed that all of the quantitative measurements of species growth were distributed in the positive direction of the 1st axis. The highest positive correlation with the 1st axis is in Jalayer Saveh and 2nd axis in Nimvar Mahalat. Sand and N in the first quarter (Sarabadan Tafresh and Jalayer Saveh), altitude, slope and P in the second quarter (Nimvar Mahalat) and C in the fourth quarter (Jaftan Tafresh) are the most important affecting factors on distribution of Almond.

This study was performed to investigate the effects of the type of cationic polymer, cationic poly acryl amid and cationic starch, on performance of nano silica for newspaper pulp and paper improvement. After preparation of chemi-mechanical pulp (CMP) and long fiber bleached Kraft pulp, they mixed together and precipitated calcium carbonate (PCC) was added as filler to the stock. As a retention aid system, the composition of cationic starch+nano silica, and also the composition of cationic poly acryl amid+nano silica were added to the stock. The pulp drainability, first pass retention and also newspaper structural, mechanical strength and optical properties were measured and the obtained data were compared with the witness data. The witness samples were the treatments that used only cationic poly acryl amid as retention aid. The analysis of results showed that the cationic polymer factor had considerable effects on performance of nanosilica for newspaper pulp and paper improvement. The stock that had been treated with the composition of cationic starch +nano silica had better and more drainability and higher first pass retention compare to the stock that treated with the composition of poly acryl amid+nano silica. And also the hand sheets that made with the composition of cationic starch+nano silica, had better formation quality, less porosity and higher mechanical strength properties in higher filler content in paper compare to the hand sheets that made with composition of poly acryl amid+nano silica.

This research focused on determining the possibility of separating different percents of Beech and Hornbeam species based on two methods of spectral reflectance assessment and classification using landsat imagery in a northern forest of Iran. To do this, Landsat7 ETM+imagery of the study area for 24 June, 2000 (middle of germination season) were provided. The 100×100 m (1 ha) sample plots with 90m distances from each other over 3 areas containing Beach and Hornbeam mixtures were transmitted from forest type map on a 1: 25000 scale. Four groups were determined after field inventory, I) pure Beech, II) 80% Beech and 20% Hornbeam, III) 70% Beech and 30% Hornbeam and IV) 60% Beech and 40% Hornbeam. To avoid road reflectance interference with tree reflectance, sample plots were selected with 60 m distance from roads. Followed by digitizing the roads and plots, the images were geometrically corrected at the ortho level using 13 ground control points. Then, the digitized roads and sample plots were overlaid on 6 bands (1, 2, 3, 4, 5 and 7) of the ETM+imagery and their pixel data were extracted. In the next step, the obtained data was statistically analyzed. The differences among the selected groups were compared via t-test method. The results showed the capability of ETM+imagery in separating the pure Beech from the mixture of 70% Beech and 30% Hornbeam and 60% Beech and 40% Hornbeam. Then, the images were classified using a Maximum Likelihood Algorithm. Based on the classification results, the maximum likelihood were measured with 63% total accuracy and 44% kappa coefficient. The results of comparing four above mentioned groups using maximum likelihood classification method were in accordance with the results of applying their pixel values.

Influence of the oleothermal treatment as one of the thermal wood modification techniques on physical and mechanical properties of beech wood was studied in the current research work. For this purpose, beech wood samples were cut with sizes of 20×20×20 mm (r×t×l) to determine the physical properties and samples with sizes of 20×20×140 mm (r×t×l) to determine the mechanical properties. The samples were treated in sunflower oil at temperatures of 200, 230 and 260oC for 30 minutes. The wood samples were soaked in water to determine the water absorption as well as the swelling properties. Bending strength as well as the impact load resistance was determined in the treated and untreated samples. Results revealed that the Oleothermal treatment of the wood reduced the water absorption as well as the swelling in beech wood, significantly. Treatment of the beech wood in sunflower oil enhanced the water repellence effect (WRE) and the anti-swelling effects (ASE). It was also revealed that mechanical properties (bending strength as well as the impact load resistance) were reduced by increase of the treatment temperature.

Seeds of Persian oak from three altitude regions of low, middle and high (1300, 1700 and 2000 meter of sea level) in Noorabad forests of Lorestan province were collected to investigate the effects of some morphological traits and altitude origins of seed on growth traits of seedlings. After measuring of seed morphological traits such as length, width, volume and number of seed per kilogram for each maternal tree, seeds were sown in common garden of Yasuj University. Then, germination rate, growth parameters like height, collar diameter, leaf number, volume and survival rate of seedlings were measured. The results showed that except of seed length, all morphological traits of seeds were different among three altitude origins. Although no differences was observed among germination rate of different altitude origins, but seedlings from low and high altitude origin showed significantly highest and lowest values of seedling vigor index, growth parameters and number of green leaves to total leaves. Also survival rate of seedlings from low and middle altitudes origin had highest and lowest values, respectively. Results of correlation analysis revealed that morphological traits of seeds were positively correlated with germination rate and growth parameters of seedlings, but there was not any significant correlation between seed morphological traits and survival of seedlings rate. In addition, the results of this research illustrated that the usage of larger and heavier seeds from low altitude origins can be conducted to more successful in plantations of Yasuj during first year of growth.

In this study, kenaf bast and stalk fibers properties studied to determined their potential in reinforcing of polymeric composite as well as their ability in cellulose extracting process to achieve interested applications such as producing micro and nano cellulose. Chemical pulps from kenaf bast and stem fibers were prepared using Soda-AQ process by using the 15% NaOH and 0.1% AQ. A three-stage bleaching procedure was carried out, including a DEpD stage for increasing the cellulose content in the produced pulp. The morphology of the obtained fibers were characterized by environmental scanning electron microscopy (ESEM). Microscopy studies revealed that the pulping and bleaching processes separated the fiber bundles to individual fibers, and caused a significant decrease in their diameter. The analysis of the chemical composition indicated an increase in the cellulose content after the chemical treatments. FTIR results also displayed that the chemical treatments could successfully be used to remove lignin and hemicellulose. Thermogravimetric analysis (TGA) revealed that the thermal stability increased in the materials having undergone pulping and bleaching. The TGA results also demonstrated the higher resistance towards heat for both treated and untreated kenaf bast fibers compared to stem fibers. X-ray analyses pointed at a higher crystallinity for the chemically treated fibers, and the highest crystallinity was found for the treated kenaf bast fibers. Finally, it is found that one could be able to produce reinforcing fiber of this plant, considering in all cases kenaf stalk shoed better results comparing to the bast fiber.

Lately, the tree crown dieback is encountered as an important problem in the northern forests. The main goal of this study is investigation on spatial distribution of the tree crown dieback in relation to primary and secondary topography characteristics and distance from river and roads using terrain analysis and GIS. A 100×500 meters random systematic sampling network with 0.1 ha sample area was designed in GIS and applied on the district 1, Dr. Bahramnia educational forest. The location of trees contain the tree crown dieback were registered using GPS in each sample and was imported to GIS. The digital elevation model (DEM) of the study area was generated using the interpolating of contour lines from 1: 25000 topography map and the primary and secondary topography characteristics and distance from river and roads were produced using terrain analysis and GIS. The digital values of location of trees contain the tree crown dieback were extracted on produced maps. The impact of selected factors on the tree crown dieback was assessed using relative effect (RE) method and principal component analysis (PCA). The results showed that the north aspect, 300-400 meter mean sea level altitude, the 30-40 percent slop, the 150-200 meters distance from rivers, the 1-100 meters distance from roads, the shaded relief of 0.4-0.5, solar radiation of 1500-1750, wetness of 15-17.5, profile curvature of 0.1-0.25 and plan curvature of 0.3-0.6 were more effective on the tree crown dieback. The results of PCA analysis also showed that four factors of solar radiation distance from road and river and slop with attending on four axes and 75 percent variances have been effective on tree dieback.

For achieving appropriate knowledge on biodiversity with a minimum cost and time to obtain a sustainable forest management, some applicable indices are needed. This study was attempted to describe some spatial structure indices as well as to quantify beech and oak spatial structures in Gorazbon district of Kheirud forest. The indices of uniform angle (UAI), mingling (DMi), DBH dominance (TDi) and DBH differentiation (Tij) were applied to investigate of positioning, mixture and DBH status of neighborhood trees. For this aim, a total of 2149 beech structural groups and 357 oak structural groups were analyzed using Crancod (Ver.1.3) software. The average values of UAI, DMi, TDi and Tij were calculated 0.58, 0.27, 0.53 and 0.45 for beech and 0.57, 0.74, 0.56 and 0.37 for oak respectively. The DMi clearly showed the difference between beech and oak, whereas the values of UAI, TDi and Tij were approximately the same for the studied species. The values of absolute discrepancy algorithm, which employed to quantify difference between beech and oak spatial structures, were 8.8%, 59.3%, 6.2% and 19.2% for UAI, DMi, TDi and Tij respectively. Because of the ability of these indices to precisely demonstrate the differentiation of stands in succession stages and their applicability for comparing the studied stand with others, they can be considered as useful tools for sustainable management.

Chestnut-leaved oak (Quercus castaneifolia) is the most important species that its regeneration is limited by several problems such us pests and the fungal diseases. In order to isolate and identify the fungi associated with oak seed and pathogenicity of certain fungi on seedling, sampling carried out during 2007 in Loveh forest and Golestan park of Golestan province. Collected seeds then surface sterilized with 0.5% hypochlorite, each section of seed tissue cultured on potato dextrose agar media. After sub-culture and providing of the fungi pure cultures, Fusarium oxysporumisolated and identified by spores characteristics, their size and color with 28, 16, 56, 40 frequency percentages in Loveh forest and 20, 12, 12, 32 frequency percentages in Golestan park. The frequency percent of the fungi in Loveh forest (35) is the higher than Golestan park (19). pathogenicity test, was performed by inoculation of spore suspension (2×106) on collar. The re-isolation of test fungi was attempted after 6 weeks, using PDA. The sections were taken from roots near the stem base. Symptom of disease was including spot wilting on leave and rot root seedling. After the re-isolation, F. oxysporum was identification that is indication this fungi is pathogen on seedling oak.