Journal of Wood and Forest Science and Technology
Year:2013 | Volume:20 | Issue:3|Papers Count:14

In this study, three common change detection methods including post classification, differential NDVI and PCA were compared using 1987 TM and 2001 ETM+ imagery to determine the kind and rate of forest extent changes in Golydaghi forestry plan. After geo-referencing of images, training areas from forest and non-forest classes were selected and classification of images was done using maximum likelihood classifier. Accuracy of classified images was assessed using some samples ground truth. Results showed that overall accuracy of TM and ETM+ classified images were %92.02 and %92.66, respectively. The classified maps were crossed to produce the changed forest map. In differencing NDVI method, NDVI indices were created for two dates and differenced each other. Thresholds of change were determined using NDVI values of 80 control points from unchanged forested and non forested areas and the change map was created using applying two standard deviations (SD) thresholds. Results showed that applying two SD could mapped changes better, compared to one SD. In the one date differential PCA, first component of PCA on the TM and ETM+ images were selected and differentiated each other. In two dated PCA, third and fourth component of PCA of whole TM and ETM+ images were selected and one and two SD thresholds were applied for changes mapping. Generally, accuracy assessment of change detection methods using ground truth maps showed that post classification method could better mapped changes with overall accuracy of %85.13 and about 0.51 Kappa coefficient compared to other methods.

This paper lists recent findings of macro fungi of beech stand in Mazandaran province in north of Iran. The list contains data on the occurrence of 100 species of macro fungi, 41 of which are new to Mazandaran province, 24 new Iranian fungus-beech associations, and 11 have not p and previously been recorded from Iran. Russulaces and Polyporaceae are wood inhabiting and 43 grow on soil. Edible and poisonous species are 42 and 10 respectively. Study on macro fungi distribution pattern showed that northern slopes consisting 32% of species diversity had the highest diversity and southern slopes having 13% had the least diversity. Result of this study increases the information about diversity and distribution of macro fungi in beech forests of northern Iran.

This study conducted to evaluate the possibility of making plywood from Ecalyptus Comuldulensis wood using oxidation of layer surfaces and application of nano-clay as adhesive filler. First Ecalyptus wood layers treated with hydrogen Peroxide and sulfuric acid using 50 gr/m2. Nano-clay was added to UF resin at three levels (1.5, 3 and 4.5 percent) based on resin solid content. Modified resin with nano-clay were applied on treated layers. Oxidated specimens were evaluated using FTIR spectroscopy. Control specimens were made using untreated Ecalyptus wood layers and UF resin and wheat flour as filler. All boards were made under press pressure of 150 kg/cm2, 160oC and press time of 4.5 and 5.5 minutes. Finally boards strength was evaluated following ISO standard. Results showed that oxidation of layer surfaces and application of nano-clay as filler had negative effects of plywood when UF resin is used. Analysis of results using ANOVA technique showed that differences exist among all tests except effect of oxidation on MOE parallel and perpendicular of Fiber were significant.

Salinity is one of the most important abiotic stresses that according to its negative effects on plant growth, reduces lands’ potential productivity. Seed germination is the first stage of plant development, in which plant encounters salinity of soil. Thus, study of plant response to salinity in this stage can have an important role in determination of plant salinity resistance. The salinity resistance of plant can be determined in short time. In this study, in order to identify salinity resistance of three Eucalyptus species (E. microtheca, E. camaldulensis, E. saligna) in germination and initial growth stages, using MS media culture in vitro condition and using completely randomized factorial experiment with 3 replications their seeds were exposed to 6 salinity treatments, including 0, 50, 100, 150, 200 and 250 Mm NaCl in laboratory condition. Germination percent, germination speed, seed vigor, root and shoot length, root and shoot fresh weight, root and shoot dry mass and total biomass were measured and used as salinity tolerance index (STI). E. microtheca was more salinity tolerant than E. camaldulensis and E. saligna. In order to achieve more confident results seeds of these 3 species were planted in different salinity classes of natural soil. After comparison, it was determined that results were quite consistent.

Fruit trees are one of important components of forest ecosystems, that their protection regarding to their important roles in ecosystem is one of the important aims in global protection structures. On the basis of fruit trees importance from ecological and economical aspects the aims of this study was to compare the spatial patterns of fruit species in managed and unmanaged forests. The study site was located in Neyrang-Noshahr forest of Iran. Two managed and unmanaged compartments were selected with are of 51 ha and 40 ha respectively with approximately similar physiographical conditions. Full inventory of fruit trees along with determination of special position were done. Ripley’s K-function was used to analyze the spatial pattern of fruit trees. The null hypothesis was a random distribution of fruit trees, which was tested by Montecalo simulation. Results showed that species of Crataegus aronia, Diospyrus lotus, Mespilus germanica, Prunus divaricata, and Ficus carica existed in both managed and unmanaged forests. However, the frequency of Crataegus aronia and Diospyrus lotus were more than other species in two compartments, while frequency of Diospyrus lotus in unmanaged forest was more than managed one. Spatial pattern of fruit trees in two compartments was cluster in short distances and then random in larger distances. Less frequency of Diospyrus lotus in managed forest in comparison to unmanaged forest was due to cutting this species by villagers in managed area which caused increased clustering pattern in short distances (up to 17m). Finally, we conclude that the spatial pattern of fruit trees in managed forest has changed slightly compared to unmanaged forest, due to high frequency of seed production and being pioneer and low demanding behavior of this species that reduced the impact of management.

In this study, the effect of clay nanoparticles on the mechanical and physical properties of wood plastic composite were studied. For this purpose, the weight ratio of 50% wood flour was mixed with 50% polypropylene and 0, 3 and 5 percent nanoclay based on polypropylene and 4% modified polypropylene with Maleic Anhydride based on polypropylene were used. First, the ingredients were mixed using the extruder and then, the final panels were produced by hot pressing. Mechanical tests including tensile, bending and screw withdrawal strength and physical tests including thickness swelling and water absorption after 2 and 24 hours of immersion were performed. Results showed that with increasing 3% nanoclay, the mechanical properties of wood plastic composite increased and then decreased over nanoclay loading more than 3%. Moreover, water absorption and thickness swelling decreased by addition of nanoclay to composites.

The trend of development in pulp and paper industry is to have higher filler content in writing and printing papers. However, the strength of paper will be reduced by increasing filler content, despite of maintaining many benefits such as improving the optical properties. In this study, the effect of different consumption levels of GCC and clay fillers on the strength and optical properties of a furnish containing 70% hardwood CMP and 30% bleached Softwood kraft pulps, was investigated. The results indicated that, by using GCC filler, in comparison with clay, it is possible to produce writing and printing paper at higher brightness and strength properties.

In this paper effective factors on forest degradation and impact of moving out livestock in district 14 of the country’s northern forests was studied primarily from environmental and economic perspective. Following implementation of relocation project of livestock holders, two categories of participants consisting of forestry experts and households were surveyed. The results showed that forestry experts believed on different sets of factors affecting forest degradation among which two were considered as more important.1) Increasing rate of livestock population and, 2) Presence of livestock in the forest. On the other hands, the livestock holders in the forest believed that the degradation intensity were a function of grazing intensity, the stand seedlings and tree branches, frequency of livestock movement on forest floor and resulting forest soil compaction. From their point of view, protecting forest from this destructive impacts can be achieved through such means as 1) Translocation of livestock from forest areas followed by their establishment in lower land ranches in the area together with supporting the livestock holders with foraged and, 2) More importantly, providing employment opportunities for the transferred livestock holder communities. The study showed that seedling survival rate following livestock withdrawal was significantly enhanced in the affected forest areas. Seedling survival rate after withdrawal livestock from the forest is improved, that was statistically significant. Based on calculations, if livestock are removed from the forest area, annual revenue from the forest alone would be increase 1.6 fold relative to the situation prior to livestock moving out.

This study was carried out to provide improvement of recycled paper strength made from OCC. Chemical treatment of OCC pulp was carried out using 1% sodium chloride as ion exchange stage and then extraction by 3% and 5% sodium hydroxide based on oven dried pulp. Slurry temperature during the chemical reaction was adjusted to 25 and 70oC. Handsheets were made based on a new standard method by KCL sheet former using a closed water system. Water retention value (WRV), sheet density and strength were measured to characterize the treated fiber properties. No significant differences in WRV were found among control and treated pulps despite of maximum increasing of 25% applying 3% NaOH, ionic exchange and room temperature. The mentioned condition was selected as the best condition which significantly improved apparent density, burst strength, tear strength and RCT.

Recognition of the effective soil factors on the distribution of Hawthorn tree provides sufficient information about this species aiming its reforestation with different purposes. In order to find out the site demands of Hawthorn (Crataegus spp.), the main habitats of this species were identified in Kermanshah province, western Iran. In this study, altitudinal distribution of hawthorn was found by determining the minimum and maximum of its distribution. Twenty eight circular sample plots (each 500 m2) were laid out in different combinations of the above mentioned site factors. Moreover, the physico-chemical soil properties of the study sites were studied. Principal component analysis (PCA) was performed to identify the variables and their relationship with species distribution. In general, results showed that only the pH of soil was the effective factor on Hawthorn distribution, and this species prefers slightly higher than neutral soils. The other factors as: Silt, Sand, Clay, Caco3, C% and EC did not have any effective role on this species distribution.

Wood fungi are plant pathogens, these fungi are causing decay in forest trees by decomposition of cellulose, hemicellulose and lignin. The aim of this study was to investigate the relationship of trees decay with diversity of wood fungi, type and diameter of host tree and some of physiographic factors as well as estimation of the number of infected trees by wood fungi in district one of the Education and Research Shastkolate forest of Gorgan. Inventory of the trees infected by xylophillous fungi was carried out using two strip transects, and all the infected trees were investigated in transects. To investigate a relationship between tree decay levels (ordinal response variable) and some predicator variables namely physiographic factors, host, hosts diameter and the diversity of xylophillous fungi, ordinal logistic regression was used. In this study, five species of trees namely, Fagus orientalis, Carpinus betulus, Quercus castaneifolia, Acer velutinum and Parrotia persicaas the host and 9 species of xylophillous fungi were identified in the study area. Abundance of host species and xylophillous fungi increased at the end of decay classes. In this respect, there is a significant difference between the levels of decay classes. Number of trees with decayed wood in the study area of 1405 was estimated. Fomes fomentarius with 36.76 percent have the most percentage of infection and Ganoderma austral with 1.47 percent have the lowest percentage of infection for the trees. Physiographic factors, the type of host tree and diameter of host trees in trees decay by xylophillous fungi were ineffective, and diversity of xylophillous fungi was the most effective factor in trees decay. With increasing of the diversity of xylophillous fungi, tree decay is accelerated.

Birch (Betula sp.) is considered as a survivor of Caspian primary forests and one of the extinct forest trees in Iran. In our country, Birch species is endangered because of limited distribution range, unfavourable habitat conditions, lack of regeneration in natural habitat and inability to reproduce sexually in natural condition. Therefore, using the technique of in vitro is very important to support this species. The objective of this study is to optimize culture medium and surface sterilization treatments for B. litwinowii micro-propagation, that is one of known Birch by use of nodal explants. Nodal explants were collected randomly from 4-5 years old of birch seedlings and sterilised by applying different treatments in both MS and WPM medium with various concentrations of BAP and NAA hormones were cultured. The obtained data were analyzed based on completely randomized design using SPSS and MSTATC software. The results revealed that HgCl2 (0.1% for 7 min) was the best treatment for surface sterilization of nodal explants. The MS and WPM media supplemented with various concentrations of hormones were suitable for culture establishment of nodal explants. More than 70% of single lateral bud nodal in both mediums becomes to leaves. Finally, 10% of nodal explants are able to produce shoot and roots in WPM medium.