نشریه علوم و فنون منابع طبیعی
سال ششم شماره 2 (تابستان 1390)

Nowadays, in many countries, water erosion process and that's results is one of the most important bioenvironmental problems, therefore, the study of this process is necessary. Towards this attempt, Nomeh Rood watershed with an area 50 Km2 was selected. This area was located in the north of Iran and south of Nour city. In this study the Land use, slope, Aspect, soil types and geomorphology maps were intersected، in order to prepare work units map. In each work units، the experiments run were taken place by using rainfall simulator through failing rainfalls with the intensity of 52/8 mm. h-1 and 30 min duration on a 0/0625m2 plot with three replicates. The statistical Analysis، with using ANOVA، showed that there is significant difference between runoff generation suspended sediment and suspended sediment concentration with in 0. 05 confident level. Generally, the rangelands from to view these points are on the first level and the non crop land areas are on the last level.

Undoubtedly, regional topographic condition is one of the most important parameters that influence to the type of precipitation, precipitation system and it's gradients. In north of Iran, to be close the northern mountains and the sea in some areas "less than 10 km in some areas" and existence of Alborz mountain caused a variety of precipitation systems in the short interval strongly dependent on topographic conditions of the region. In this research the effect of topographic conditions and the role of the Alborz mountain range studied on types of precipitation, amounts of annual rainfall and it's gradient. The results showed, in Mazandaran province suggests non-uniform changes in precipitation gradient in different elevation classes and different geomorphologic disturbance gradient in the plain areas and mountainous topography influence on the precipitation system it's gradients.

One of the important features of the trees stability is the slenderness coefficient which is the result of diameter at breast height on the height, could be a very good predictor in the tending operation which help, the researchers, such as Burschel and Huss, have claimed different scales for evaluating the stability and the growth of the trees. Among the places which had been forested with the piles kind in the north of the country, we can mention some place such as Babol kenar, Ezdarsi (East Bandpay) and Kamel besar (West Band pey) in the jungle area of the city of Babol. With regarding the importance of the slenderness coefficient in the tree's stability, the stability of the hand plantedstand of piles (Cupressus sempervirens L. var. Horizontalis) according to the Burschel and Huss scale had been studied. In this survey, one hundred percent statistics for the aim of data gathering (height and diagonal) for the nomination of the slenderness coefficient was used and with the help of this for the type soft woods according to the Burschel and Huss scale, the comparison of the stability of Cupressus sempervirens L. var. Horizontalis in those places (that was mentioned) was done (the slenderness coefficient less than 45 demon starting unstable, and more than 100 is very unstable). Finally the “Anova and Duncan“’s test the gained features in the slopes and the directions related to each place, were compared, separately. In this research the slenderness coefficient for the internal places was nominated 95 Ezdarsi 82.3 and Kamelbesar 81.4 percent. According to the Borshel and Hass scale it was declared that these 3 places for having the slenderness coefficient between 80-100 are unstable.

To reach a dynamic forest and preserve the original species in forest and help the natural life restoration the exploitation method of close to nature can be the most essential technique in preserving the north forests of the country. In this study the diversity of tree and grassy species was considered in the gaps made due to single selection cutting in the seventh series Siyahkal shenround forests parcel 704. At the beginning by spryer forest 35 gaps in three groups with the menstruations 100- 200, 200- 300, 300- 400 square meters were assigned and randomly from each group 5 gaps and totally 15 gaps were selected on account of inventory. In order to consider the grass covering along the length of two diameters of gaps, the pieces with size of 2´2 meters, and one meter distance from each other were performed systematically. The study showed that with increase of gaps surfaces the number (richness) and quantity (evenness) of the tree species increases but it doesnt have a specific order. Also, 20 botanical species in the gaps of 1-2R, 21 botanical species in the gaps of 2-3R, 23 botanical species in the gaps of 3-4, was observed. To measuring the different diversity indexes showed that in the gaps with 300- 400 square meter, the shannon winner index with the amount 2.799 had the highest value and according to the calculated value and importance of each species (SIV) in each of the gaps the most importance was allocated to the fagus species and the lowest importance was allocated to, Honey locust, malus and pyrus species.

The objective of this study was to evaluate the soil invertebrates diversity within plantations of Alder (Alnus subcordata C. A. Mey.), Maple (Acer velutinum Bioss.), Oak (Quercus castaneifolia C. A. Mey.), Cypress (Cupressus sempervirens var. horizontalis) with an adjacent mixed broad leaved forest in Darabkola (Mazandaran-Iran). In the time of study the plantations were 20 years old. For this purpose, invertebrates were seasonally sampled for one year, using 200 core soil samples (81 cm2 cross section) to a depth of 10 cm. The invertebrates were extracted by Berlese funnel and counted by Binocular. Also 200 soil pits of 100×100 cm2 and 10 cm depth were taken and adult earthworms were collected by hand counting. More over, various parameters of the stands and soils were measured in each microsample plot. The results of this research showed that the forestation activities with hardwood tress improves the diversity of the soil invertebrates. The soil invertebrates diversity in the Alder plantation was significantly greater than the other treatments where as the diversity in the Cypress plantation was significantly lower than the other treatments. Also the analysis of PCA showed that the parameters of temperature, crown canopy, relative light intensity, moisture content of soil and litter and the amount of P/C of litter took an important role in seasonal differences of soil invertebrates diversity in all treatments.

In the present research an attempt has been made to account for the effective idiceson the export of the country’s wooden furniture. Presented in eight major classes, thisclarifying account aims at developing the export rate of the wooden furnitureindustry’s various products and finding access to the regional markets both of whichare envisaged in the country’s macro objectives for industrial and economic growthand are further in accordance with the Outlook Plan. The methodology is ofdocumentary and process-oriented approach in which a standardized questionnare wasdesigned and handed out among 90 sample subjects. Also included are the views of theprofessionals and figures of the field at the university and wooden furniture industrylevel as well as other related fields. The saliency of the major indices has beenidentified through Delphi’s method in a meeting with the wooden furniture specialists.The requirements of the Likert’s spectrum approach with and without application ofthe saliency coefficients for each index have been met and the final ranking of theeffective indices assessed. The results show that unlike what many scholarsascertained the indices of knowledge and management, governmental supports fordomestic producers and innovation in various aspects of the production technology,packing, product design and etc. are successively salient. The indices of humanresource, advantage of the relative competition, economy (expenditure), raw materialand the final product, and the environmental limitations signifying the uncontrolablefactors are of the next saliency level accordingly. Thus, it can be concluded that thefailure of the wooden furniture industry in exporting its products and gaining a share inthe regional markets, to the benefit of such countries as China and Turkey, must besought more in the level of employment of the knowlagable managers, introduction ofthe applied trainings, serious governmental supports for the domestic producers andexporters as well as the necessitating innovation in various aspects than the shortage ofthe raw material and production structure.

The purpose of this research was feasibility usage of willow wood by different mixing ratios with other conventional wood species from Mazandaran wood and paper factory, on the optical and mechanical properties of newsprint from a chemi/mechanical pulp (CMP) based on Factory conditions. Therefore some handsheet papers were made of pure and mixed pulps (by willow wood pulp and mixed wood pulp) componds. Mixing ratios include 15, 30, 45 and 60 percent of the willow pulp with factory pulp were selected. After making the hand sheets, the optical properties such as brightness, opacity, yellowness, and mechanical properties include tear, burst, tensile, breaking length and stiffness were measured. The results showed that wtih increasing of the mixing ratio of Willow pulp, the amount of hand sheets brightness was reduced. However, the yellowness and opacity was improved. The highest mechanical properties of hand sheets such as burst, tear, tensile, breaking length, stiffness were observed on 30%, 30% and 60%, 45% and 60% of mixing ratios, respectively.

In this research, the relation between climate and growth rings width of oak wood has been investigated in region 32 of Talimroud forestry plan which located in Dohezar Tonekabon forests. Hence, three sound oak trees were selected, then from each of them a disk in the breast height were cutted. Then, the prapered discs transferred to Tehran university laboratory and their growth rings width was measured by binocular. After that, the relation between these amounts and climatic conditions (temperature, precipitation and relative humidity) was calculated. Results showed that changes rate of growth rings width have increased in the first years of growth and then decreased in the final years of tree life. A negative relationship between the growth rings width and precipitation was observed in April and there was no significant relationship in other months. There was a negative relationship between growth rings width and average monthly temperature in January, February, March and July. Also a negative relationship between growth rings width and average minimum temperature was found in January, February and July. Study on relationship between growth rings width and relative humidity showed that the maximum correlation occured in November (R2=0/153) and the minimum correlation occured in February (R2=0/001).

For investigation of withdrawal strength in dowel joint, the effect of doweldiameter (6,8 and 10 mm), distance between dowels (20,25 and 30 mm) andwood type (Beech, Alder and Spruce) were studied. The dimensions of malcingT-form Joint in dowel Joint were 5*5*2.5cm. Type of wooden dowel using inthis research was carpinus betulus which is the common dowel in malced. Also,PVA was used in dowel joint a glusive. According to, 27 treatment and 4replicate, totaly 108 T-shape samples were tested. The results indicated that thehighest and lowest withdrawal strength has been shown in beech and spruse,respectively. By increasing the dowel diameter from 6-8mm, the withdrawalstrength increased, and with increase of dowel diameter to 10mm, this propertydecreased. The highest withdrawal strength was related to 25mm distance.

The purpose nose of this research is to study the effect of coupling agent on microscopy and water absorption properties of nanocomposites which are made by residual sulfite pulp paper fiber and cement. Eight treatments as variable factors including the effect of the two levels of coupling agent based on Amino Silane (0,6 percent of fiber weight) different percentages of Nano silica (0,0.5,1,3 in respect to dry cement weight), the ratio of water and and fiber at 10% on water absorption property of samples were investigated. All specimens are made and tested during the BS 1881: Part 122-1983 standard during three solid, liquid and final blending stages. Microstructure properties are analyzed by Scanning Electron Microscope (SEM). The results demonstrate that water absorption of fabricate nanocomposites decrease compared to control sample which had 10% Asbestos fiber by enhancing nano-silica particles. Additionally water absorption is decreased by adding the coupling agent. On the other hand water absorption decrease by the synergic effect of nano-silica and coupling agent. However, the specimen with 3% nano-silica and 6% coupling agent had the lowest water absorption compared to others. Further- more, improving microstructure of bio-nanocomposites by adding the coupling agent was shown by SEM images.