Journal of Forest and Wood Products
Year:2013 | Volume:66 | Issue:3|Papers Count:11

The aim of this research was to determine the number and volume changes after the implementation of a 10 years forest management plan period and comparing of these changes with the aimed purposes. Inventories have been done systematic random sampling in 1000 m2 area plots. Diameter at breast height, control trees height and quality of first 6 m trunk length of trees with dbh more than 42.5 cm is measured and estimated. Volumes of inventoried trees were calculated based on forest management plan Taryf. To compare the mean volume and number of trees per hectare in the two inventories volume table, t test was aplicated. In order to compare trees height curves at the beginning and end of period, cloud points of control trees was drawn and then modeling with regard to it. The results showed that during the implementation, mean volume has increased 10 sylves per hectare and 47 trees has decreased in hectare, but these changes were not significant regarding to t test (d.f=32, P<0.05). After implementation, the height curve of tress and volume of trees with high degree of quality has increased. Percent volume per hectare of beech species is passed from planned mode (ideal mode) and the species hornbeam and oak nears to ideal mode. The other species have not only failed to approach the ideal goals, but also we are far from it. Reforestation rate performed is almost 50 percent of planned.

Phytoremediation technology is the use of plants to remove pollutants such as heavy metals from the environment and accumulation of them in different plant tissues. In this study the ability of two plant species; Robinia pseudoacacia and Fraxinus rotundifolia to remediate the cadmium, was compared.90 two-years old seedlings of these two species were cultivated in Alborz Research Centre of Karaj in March 2008. The cadmium chloride solutions with the concentrations of 0, 250, 500, 1000 and 2000 mg L-1 were foliar application on the seedlings in June 2009. Then the leaves were collected from the seedlings during two times a year, in August and at the beginning of autumn. Moreover, some samples were supplied from twigs, roots and pot soils in January 2009. The concentrations of cadmium in samples were determined by ICP and the data were analyzed by completely randomized design in SPSS. Results showed significant different between two species in all the organs. The amounts of Cd concentration in F. rotundifolia were higher than R. pseudoacacia in the mature leaf, fall leaf and roots. The amount of Cd in the stem of R. pseudoacacia was higher than the stem of F. rotundifolia. So, it could be concluded that F. rotundifolia is more valuable in accumulation of the cadmium in short time and R. pseudoacacia is more suitable in long time. The maximum concentration in mature leaf of F. rotundifolia was 461.5 mg-1 kg. Therefore, it may be announced as a hyperaccumulator species based on previous studies.

In this research, we tested biasedness of canopy cover and density estimation of forest trees and shrubs by the use of line sampling method. For this aim, locations and crown width of all trees and shrubs with crown width more than 10 cm in a 53 ha forest area in Ardal located in Chahar- Mahal and Bakhtiari Province were recorded. Then, 100 segments of line transect with various length (50, 100, 150, 200, 250, 300, 350 and 400 meter) were sampled, and this procedure was repeated 100 times. We used ANOVA to see if there is any significant differences between the estimated forest density and canopy cover with the different transect length. Results showed that, there is no statistical significant difference between various transects length for both variables. Also, as could be expected, by increasing the length of transects, the coefficient of variation was decreased and this decrease were negligible for transects longer than 200 m. This means no more precision could be achieved by more effort on measuring sample lines longer than 200 m. Analysis showed that the line transect sampling method is biased (over estimate) and the average relative bias were between 4-6 and 6-10 percent for tree density and crown coverage, respectively. Based on results, it can be claimed that, by considering the ease and speed of transect sampling method, the bias of estimates are negligible.

Mountainous forest communities of Irano-Turanian vegetation region are characterized with Juniperus excelsa. These forests have involved too many changes in the past and nowadays mostly are not integrated. But there are still some dense or broad stands. In this research, we have studied such these communities and their ecological properties in north of Tehran to northwest of Semnan province. A data set including floristic data according to Braun-Blanquet method and environmental variables were provided. To classify the vegetation, TWINSPAN and analyzing vegetation data with JUICE, and to investigate the species-environment relationship, ANOVA and Ordination (CCA and PCA) was used. According to the results, the vegetation was classified into six groups which were specific in floristic composition and ecological characteristics, and were described by their site properties, constant and indicator species. These groups took placed in three forest communities: Juniperus excelsa - Rhamnus pallasii, J. excelsa - Cotoneaster nummularius and J. excels - Lonicera iberica. The first one is significantly related to lower altitude and soils with poor nitrogen and organic matters, the second community is interested in upper lands and nutrient soils with a high saturated water capacity and the third one comprises stands impressed by the moist climate of the Hyrcanian region.

This study was carried out in order to study of effect desiccation sensitivity and seed moisture content (SMC) on primary features of seed and seedlings of A. monspessulanum sub. turcomanicum with aim to determine seed storage behavior. Pure and ripe seeds were collected from valley Zarrin gol of Alli- Abad city located with Golestsn province in elevations of 500 to 1100 meter above sea level, with initial moisture content 46%. Seeds were stratified for six months to overcome the seed dormancy and in order to creation 9 level moisture content consist of 45%, 40%, 35%, 30%, 25%, 20%, 15%, 10% and 5%, seeds were dried near silica gel in 25°C. All dried seeds imbibed in water for 24 h and incubated under optimum growth condition sow for 30 days using a complete randomized factorial design, with 4 replications. Characteristics of emerged seedlings were recorded every day. Results showed that A. monspessulanum shows intermediate seed storage behavior and threshold water content (TWC), critical water content (CWC), and lethal water content (LWC) get 40%, 20% and 5% for this species. Also with reduce moisture content lead to reduce seed viability, germination percentage, germination speed, germination value, germination energy and vigor index and primary features seedlings consist of length seedling, radical biomass and stem biomass. This study was a basic research and defines that the seeds of this species are not capable of long-term maintenance. To obtain the seedlings with desired characteristics moisture content should not be less than the threshold 40% at planting time.

Surface properties of cellulosic fibers can be modified by Layer-by-Layer (LbL) technique. Different factors influence the performance of LbL technique. The properties of pulp fiber suspension i.e., conductivity of the fiber suspension are of such factors, affect the results of the LbL process. In this study, the physical and mechanical properties of handsheet with basis weight of 60g/m2, made from LbL-treated recycled OCC fibers at various salt concentrations with biopolymers cationic and anionic starches evaluated. The results showed that apparent density and formation quality of handsheets made of LbL-treated recycled fibers were improved significantly, while there was no obvious change for paper roughness. Bonding ability indexes including tensile index and Scott bond were also increased significantly. Moreover, the variation of conductivity showed a dual effect on the electrochemical properties of OCC fiber surface and starch absorption. The salt concentration of 0.001M NaCl with 140mS/cm conductivity was the optimum condition for layering.

Fiberboard is one of the widely used wood-based panels for inside the building. In this study, the possible use of Basilit (BH3O3) or Boric acid with two concentrations levels, 3% and 5% for high density fiberboards (HDF) was investigated. Fire resistance properties including weight loss, the development of the flame height and physical and mechanical properties of the samples were determined. The results showed that the samples treated with 3% Basilit had less weight loss than the samples treated with 5% Basilit and control. In the case of the physical and mechanical properties, the samples treated with 3% Basilit had lowest water absorption and thickness swelling and had the highest bending strength.

This research was carried out to determine physical properties of beech wood impregnated with methyl methacrylate monomer. Test samples were prepared according to ASTM-D1037 standard. Samples were treated in the cylinder according to Bethel method at five concentration levels of soluble monomer methyl Metacrylate (Diluted in benzene), 0, 40, 60, 80 and 100 percent. Treated samples were heated in oven at 90ºC for 24 hours, then at 103ºC to polymerize the monomers. Monomer absorption percent, changes of weight, density, water absorption, and anti-swelling efficiency (ASE) were determined. Monomer absorption was 41.6, 46.1, 54 and 57.9% in 40, 60, 80 and 100% level. Polymer absorption (WPG), in the lowest and the highest treatment level were 5.3 and 22%. The results showed increasing levels of absorbed polymer, hydrophobicity and dimensional stability of samples treated increased. Water absorption and swelling volume of the sample saturated with a monomer of 100%, compared with the control sample, 54.3 and 63.5 were decreased after the longest immersion time. With increasing monomer absorption, density increased from 0.63 g/cm³ to 0.84 g/cm³ in control samples 84.0 at the highest level of monomer absorption. After 36 hours, anti-swelling efficiency of water-saturated samples treated at the highest level was 240.3% more than lowest level.

The purpose of this study is to evaluate total phenol and flavonoids and antioxidant effects of beech and hornbeam and spruce; bark. Beech and hornbeam species of northern hardwood and spruce; species of planting trees, despite of their abundance, very little information about the chemical composition of their skin and their application is presented. Antioxidant compounds that prevent disease outbreaks and destruction of food can also be extracted from the skin these plants. After preparation of the bark, acetone extracts were obtained by soxhlet. First, the amount of total phenol and flavonoid extracts measured and then for evaluating the antioxidant properties of extracts; regenerative power and hydrazyl diphenyl pykryl methods were used. The results showed that the amount of phenol and flavonoids were highest in the bark of hornbeam and lowest in the bark of beech. Test results or trapping free radicals DPPH1 shpwed inhibitory concentrations 50% acetone extract of the bark of beech, hornbeam and spruce; respectively, 07.63, 17.33 and 3.86 micrograms per milliliter, respectively. Also beech extracts has more regeneration power compare with other species.

In this research, the effect of cellulose nanofibers on the properties of handsheet paper made from industrial bagasse pulp was investigated. Nanofibers, produced from alpha cellulose of softwoods using grinding method, were added 20 wt% to the handsheet paper. Nanopaper- handsheet composed of 100% cellulose nanofibers- was also prepared. Results indicated that using nanofibers increased water drainage time of the pulp. Addition of nanofibers to the handsheets increased the optical transparency and density while sheet thickness decreased. Papers made with 20 wt% nanofibers showed higher tensile strength than those prepared with pure bagasse fibers. Nanopaper possessed the highest tensile strength. Tear strength was negatively affected by using cellulose nanofibers in such a way that the lowest tear strength obtained for nanopaper. Never eless with Addition of nanofibers to the handsheets in said conditions tear strength decrease but this decreasing of statistical viewpoint wasn’t meaningful.