نشریه علوم و فنون منابع طبیعی
سال هفتم شماره 3 (پاییز 1391)

According to importance of Querqus. castaneifolia in northern forests of Iran and its high value in reforestation and revival of destructed stands. In this research we studied the appropriate period of seed planting in nursery. For this aim the effect of sowing date on the quantitative and qualitative characteristic of Querqus castaneifolia seedlings, was studied with randomized design in two treatments with five replications. At the end of the first growth season, some quantitative and qualitative characteristic such as height, collar diameter and shoot/root length ratio and survival rate is studied and the data was analyzed by SPSS. Analysis of data showed that there is significant differences in most features between seedlings planted in autumn and early spring at 95% cofident level, Also, the autumn planted seedlings in comparison with spring planted seedlings had better physical characteristic and vitality. Although there isnt significant differences between number of roots in two treatments. The results showed that for producing resistant and strong seedlings with better quality, paying attention to ecological demand of each species and sowing in appropriate date is very important.

The main issue in design of forest roads, are proper planning, and passed the more positive and less negative. Trace the path with topographic maps and off the field as major infrastructure projects through the forest which is the most important and difficult part. The main objective of this study was prepared the map capabilities through appropriate road forest, mountain and forest stands in Series 7 of 38 sardabroud regard to technical road forest after harvesting, and also the maps needed to identify factors that influence the cross roads in the study area.These factors includes dip in the GIS maps, directions, soil, geology, type size, distance from waterways and the landscape of the region were provided with a raster format. Then, the floor plans prepared by the relative importance of classes in the range of 1 to 9 were rated.Then according to hierarchical analysis (AHP) the weight value of maps was obtained. Map data combined with weight factors in environment, GIS, maps were capable for crossing the road. The results showed that using this method, which can be potential areas for the road through the forest roads in the mountainous north and identify. Also, according to the data, including maps used in this study method can be introduced as a method for predicting the primaries of forest roads and mountain.

Cerasus mahaleb (L.) mill is one of the most important species in zagros forests. This species can be used as a pioneer element to rehabilitate in destroyed forests. So, having knowledge of ecological and some silvicultural characteristics of Cerasus mahaleb (L.) mill can help forest managers for a proper application of this species. After prepare site map, inventory of quality and quantity parameters (diameter at breast height, total height, crown percentage) was done with full callipering. The squar of this sites was 10.8 (ha). In order to regeneration study (65) plots, 100 m2 circle were used. Results showed that cerasus mahaleb (L.) mill is establish in rockness and high slopes with well drained soil. It can establish in north and eastern north aspects in surface soils. Its regeneration is low (about 40) and the suitable moist condition, is better and its insexual regeneration is extremely coppice. Soil's pH is neutral (6.5 -7).Its establishment is on the lemon bed rock. The texture of soil is Sandy- Loam, Loam, Clay, Clay-Loam, and Sandy-Clay-Loam. The most regeneration of Cerasus mahaleb (L.) mill is by shoot and less by seed.

In order to study the fit circumstances of some important measurement characteristics of Orientalis Beech such as diameter at breast height, total height by statistical models (Distributions).To meet this objective,the parcell 704 was selected with a 51 hectare measurement that contains Beech trees in different heights and age classes and healthy stand in SiyahkalShenroud forests. In this parcel the inventory net with a dimension of 100×200 meters with a randomsystematic method was selected and 20 circle sample pieces with a 10 R(1000 m2) measurement were made. In each sample piece the diameter and height of all trees with diameter more than 7.5 cm were measured. In this study Beta, Normal, Johnson SB, Exponential one and two parameter, Gamma two and three parameter, lognormal two and three parameter, weibull two and three parameter statistical distributions were used. The results obtained from the goodness fit tests showed that the statistical distributions fit power weren’t eaqual in a way that for the description of Beech tree diameter two parameter Gamma distribution is suitable and Beta distribution also has caused a suitable fit for explaining Beech trees height.

This study was carried out to effect of dead tree on the survival regeneration in ramsar safarud forest in parcel of 513 with 100 hectar in surface. Then, with a tour in forest, 30 numbers of existed dead trees in that parcel were picked up separately by species and type of dead tree. Then, according to center of dead tree, 5 numbers of case with 2*2 dimension was selected which one of them located in center of dead tree and the others established in 4 directions. For comparison dead tree affect, one sample as a control and all characteristics which affected on dead tree was selected. Results indicated that 66/66% of dead tree in stand form and 33/33% of them in fall form was established. The highest number of dead trees were related to fagus specie with 43/33%. Also, the results showed that between there is no significant difference regeneration in dead and normal trees, but there is significant difference between herb in dead and normal trees.

This study has been done to examine the different variables on mortise and tenon joint made of wood species of Beech (Fagus orientalis lipsky) and Norway spruce (Picea abies link karst) in order to predict moment resistance in 7 and 10cm from support and its withdrawal strength. The tenon joint length in 30 and 40mm, for two dried conditions (Air drying and kiln drying) was selected. poly vinyl acetate (PVA) glue was used as an auxiliary component in joints. According to the variables, with 8 treatments and 3 replicates, in totally 72 samples were made for the study of withdrawal strength in T-shape joints. The withdrawal strength and moment resistance were measured in two distance of 7 and 10cm of the support by mechanical testing machine, with a speed of 1,2mm per minutes. According to the results the interaction effects of wood species× tenon length, drying method × tenon length and in the independent effect of drying method had, significant difference an withdraw strength, 95% confident level. Additionally, independent effect of wood species in moment resistance in a distance of 10cm from the support and independent effect of tenon length in moment resistance in 7cm of support had a significant difference in 95% confident level. Also, the other parameters dont have a significant difference. In this research 30 mm joint tenon length with regard to 40mm and the Beech species compared to Norway spruce showed higher resistance.

In this study, effect of chemical treatment of rice husk flour on the water absorption of rice husk flour / HDPE composites was investigated. At the first, rice husk was milled and the flour was selected by passed of 40 + / 60 sieves. The dried flour was chemically treated by acetic acid, acrilonitrile, silane and benzoyl chloride, then the chemically treated flour was compounded with powder of high density polyethylene at 60% filler loading. in internal mixer the compounded materials were grinded and then composites were produced by injection molding method also the. rice husk flour / HDPE composites without chemical treatment and with coupling agent was produced by injection molding.Changes in the chemical structures of chemically treated flours were tracked by Fourier Transform Infra Red (FT-IR) spectroscopy. Results showed that the absorption intensity of the hydroxyl groups in the area close to the 3430 cm-1 in the interaction with sodium hydroxide (as pretreatment) and chemical treatment was dropped. The spectra obtained from samples treated with acetic acid in the range of 1740 cm-1 related to the carbonyl groups of the hemicellulose is greatly reduced. The results also indicated that the water absorption and thickness swelling of samples treated with acetic acid was similar to samples with coupling agent, also the water absorption and thickness swelling was less. The thickness swelling and water distribution coefficients of samples chemically treated with acetic acid, was similar to samples with coupling agent.

In this study the effect of clamping both ends of beam on the possibility of measuring acoustical properties (acoustical conversion efficiency, damping, and acoustic coefficient) of Scotch Pine (Pinus sylvestris L.) in both tangential and radial direction, by free vibration method has been studied. In accordance with ISO 3129 international standard, 19 visually clear wooden rectangular beams of Scotch-pine species with dimensions of 36×2×2cm (length× width×height) prepared under free vibration non-destructive tests. Effects of clamping of both ends of beam on the mentioned three factors with the results of this test in the case of free-free ends were compared. Clamping of both ends of beam increased vibration damping in comparison with bending test results. In associated with the acoustic coefficient, clamping of both ends of the beam had lower effect on this factor compared with free ends case also the results showed that there are no differences between free ends and fixed ends cases. But the results of estimating acoustical conversion efficiency in fixed end case indicated that the bending free vibration method in fixed end beam is an inappropriate method for evaluating this factor.