نشریه علوم و فنون منابع طبیعی
سال پنجم شماره 4 (زمستان 1389)

In this study, the thermal and morphological behavior of polyropylene/wood flour/montmorillonite hybrid composite was investigated. For this purpose, wood flour were mixed with polypropylene at a weight ratio of %40 to %60, and montmorillonite with 0, 2, 4 and 6 phc respectivly, 2 phc of MAPP was also used as a coupling agent in all formulations. Then samples were molded through injection, and thermal properties such as melting tempreature, crystaline temperature and crystalinity point were tested with TGA and DSC techniques. Morphological behavior of the obtained nanocomposite was evaluated by X-ray diffraction. Results indicated that Char melting tempreature, crystaline temperature and crystalinity point were increased with the increase of montmorillonite (modified clay) content; and improved their thermal stability. In addition, the morphological study of the samples showed that montmorillonite particles distributed as intercalation structure in polymer matrix, and the d-spacing of layers were decreased with the increase of modified clay content.

Thermal conductivity (TC) of Populus Alba, Carpinus betulus and Acer laetum woods at various temperatures, has been measured experimentally complying with ASTM C177 standard. Two samples with 20×20 Cm2 areas and 1cm thicknesses which have been obtained from the northern part of Iran were utilized to test their thermal conductivity. The results show that thermal conductivity of Populus Alba, Carpinus betulus, and Acer laetum increases linearly with increasing temperature. Furthermore, a tentative relationship is recommended to predict TC of the species. Finally, thermal conductivity of these three species has been compared and it has been found that Carpinus betulus thermal conductivity is higher than Acer laetum and Populus Alba.

The effect of vibration kind and direction on damping properties of wood has been studied, taking into account the specimen width in rectangular wooden beams of Silvestre Pine wood (Pinus silvestris). 39 sound and clear beams with the dimensions of 36*4.5*2 cm (LRT) (wide specimens) made from Silvestre pine wood were tested and damping factor of the first mode was determined through logarithmic decrement method in temporal field separately for longitudinal, flexural and torsional free vibration tests. Then the specimens were cut to smaller specimens of 36*2*2 cm (LRT) (thin specimens) and then were tested in the same way as the initial wider specimens. There was no effect damping of factor on width variation while different vibration directions significantly affected this property. The greatest damping size was of torsional and the smallest of longitudinal vibration test. There was no difference between LR and LT flexural damping factors. It has been predicted that in all vibration directions, every dimension of the specimens (e.g. in-situ) could be used to evaluate the damping factor of a proper piece of wood.

In this study, the effect of nanoclay particles content on flammability properties of wood polymer composite made of polypropylene and wood flour was examined. For this purpose, wood flour was mixed with polypropylene at a weight ration of 50%, and nanoclay with 0, 2, 4 and 6% respectivly, 2% of MAPP was also used as the coupling agent in all formulations. The samples were molded through injection, and flammability properties such as Char Residue, Burning Rate, Total Smoke Production, Time to Ignition and Heat Release Rate were tested according to ASTM standard. Results indicated that Char Residue and Time to Ignition were increased by increasing nanoclay particles content, however, Burning Rate, Heat Release Rate and Total Smoke Production were reduced. In addition, x-ray study of the samples showed that nanoclay distributed as intercalation structure in polymer matrix, and the dspacing of layers were decreased with the increas of nanoclay particles content.

This study examines the effect of altitude on physical properties of hornbeam juvenile wood. For this purpose, nine healthy twelve-years-old trees of Hornbeam species were selected in three altitude levels 300, 750 and 1350 meters at Mashelak forestry project. From each tree, three discs for breast height, 50% and 75% height of trees cut down. samples of discs prepared to measure physical properties such as oven-dry density, basic density, volume shrinkage and volume swelling. The analysis of variance showed that the effect of altitude on the oven-dry density, basic density, volumetric shrinkage, and volumetric swelling of hornbeam juvenile wood were significant. Trend of wood basic density and oven-dry density in longitudinal axis from the bottom to the top of tree is decreasing. The interaction effect between altitude and longitudinal axis on wood basic density, oven-dry density, volumetric swelling, and volumetric shrinkage wasn’t significant and while the longitudinal axis effect on oven-dry density and basic density was significant. The correlation results showed that relationship between density and variation dimension correlation results of wood on 750 meter is stronger than other altitudes.

Agronomy as the most important source of pooviding food for humans, has fundamentally changed the mechanism and action of natural ecosystems. Human’s utilization of natural resources is always unilateral and irregular. There is no regard to conservational aspects and it is only based on obtaining shortterm benefits. In creasing growth of population and food shortage tension, has caused more utilization of natural resources. It can lead to biological imbalance. For stabilizing natural resources it is essential to synchronize natural resources preservation with food security in order to produce more revenue for lowincome families. Agroforestry is an alternative. The object of this study is to compare the income, production and economy different systems of enbloc agronomy and Agroforestry. Data was collected with outdoor study, questionnaire, personal question and discussion with 40 Agronomy and Agroforestry users in a random sampling procedure. Results have shown that agronomy products income is more than Agroforestry products income. But total income in Agroforestry systems is higher than agronomy systems with attention to the kind of system (namely fruit, wood). Since Agroforestry systems render higher income for farmer, it can raise life level and public welfare in villages and indirectly prevent migration to cities. Thereupon Agroforestry can not only lead to natural process and stability of natural resources, but can also lead to the development of rural economy.

Khoshkedaran National Natural Monument as one of 4 protected regions of Mazandaran province enjoys a natural view and unique plant covering and is reminder of plain woodlands in the north of the country. It is necessary to recognize its plant covering and species diversity exactly in order to manage and protect this diversity against the existing destructive process. In this research, “A Survey on Species Diversity of Woody Plants in Khoshkedaran National Natural Monument” has been performed . Random sampling method is used for determining woody plants number in order to study species diversity and richness and using several circular plots with 16 m radius and measuring 804 Sq.m. in each woodland type and totally, taking 32 plots, we collected the necessary information. Then we obtained the following results by four species diversity indexes and two species richness indexes: according to the three diversity indexes of Shannon-wiener, Simpson, Mackintosh, the type Pterocaryeto- Buxetum , with the least area among other woodland types, has the most species diversity and has been ranked in the top. Type Alneto-Pterocaryetum which occupies the most area among the other woodland types has the least diversity and has been ranked third. Briloin index results are different from other indexes. According to the species richness indexes of jack knife and rare faction, type Pterocaryeto-Buxetum, has a little species richness and has been ranked fourth. Type Alneto-Pterocaryetum, has the most species richness which has been ranked first. The results show that in all woody types, except to type Pterocaryeto-Buxetum, the woody species of raspberry as an offensive species has predominated other species and is considered as a destructive agent.

Total number of women taking part in this research is 75945 in the age group of 15-64 years in the west of Mazandaran province (including the cities of Noshahr, Chaloos, Tonekabon, Ramsar). 165 women were randomly selected by 2-stage cluster sampling from 24 villages in the west of Mazandaran province. This research is of descriptive nature (ex pose facto). The findings and results of the present research indicated that there is meaningful and positive relationship between, the degree of interest in environment, the kind of environmental training and the women's role in the management of environment.

In orther to use morphometric variables of catchment area in regional flood analysis in Sardabrud ,Chalousrud and koukoursar watersheds at first , the basic raw data of annual instantaneous peak discharges for hydrometric stations in the region was collected, then the missing data was filled in and new statistics were generated. A twenty nine-year-statistical period for this case was selected .Then a homogeneity test was conducted by the use of Run test method . The new statistics of the stations was then analysed by the use of current statistical distributions in which Pearson Type III and Log Pearson Type III distributions as the most suitable statistical distribution was selected for the region through which the mean flood discharge of stations was estimated .Moreover, the morphometric variables of basins and sub basins were measured and estimated which consisted of 13 independent variables. After that, coefficient of correlation and significance level test between flood discharge and morphometric variables was conducted. The results of the study show that five out of the thirteen morphometric variables (number of stream channel , length of stream , area of the basin , Horton form coefficient and perimeter of the basins ) are significantly and linearly correlated with flood variable under study in which the number of stream channels with higher R – square (R2) was selected as the best independent variable for the formation of the linear regression equation and also for the estimation of the mean flood discharge . Then , the other significant independent variables were removed from the formation of the regression equation for their multicolinarity .

Zagros growth-place is one of the important resources of Iran that has special value regarding plant and animal species, genetic resources, woodland. Existence of various plant species and some endemic ones makes the preservation of this ecosystem necessary. This research has been conducted in parts of the woodland which is located in the west of our country. plant species richness with the application of the important indexes such as: species number, Margalef, Menhink, and plant life forms along the altitudinal gradient were evaluated. The obtained results indicated that there is a non-linear relationship between the cited indexes and altitude. The richness showed an increase in rate up to the mid-altitude (1850 m) and after that it decreases. Among them, only species richness index showed significant difference with α=0.01. Study of plant life forms showed a decrease in frequency of Therophyte rate to the higher altitude, and other life forms increase. In general, Therophyte with 48% and Phanerophyte with 9% respectively have allocated the maximum and minimum of frequency to themselves.

Identity and introduction of plants collection is one of the important works that is used to optimize utilization from natural resource of a region. The findings of these efforts provide basic and fundamental information that is used in different fields of study, biology, agriculture, pharmacy and industry. In this survey the flora of protected region of Sisab has been studied. Sisab region is situated in 42km from Bojnord. Its lowest and the highest altitudes are 1300 and 1570 meters respectively. The method of plant collection in this region was classical method of regional floristic studies. Collected plants were recognized and determined as families, genera and species. Flora of this region includes 106 plant species that belong to 88 genera and 30 families, the important families are Poaceae, Astraceae, Labiatae, with 23.2%, 13.8% and 6.5% respectively. Studying of plants life forms by Raunkiaar method showed that hemycryptophytes with 44 percent (47 species) of species are the most frequent life forms. High percentage of hemycryptophytes indicates that the area has cold mountain climate. Therophytes with 37 and chamephytes with 10 percent of species are less important. Investigation on geographical distributaries of plants species showed that 69 percent (74 species) of the species belong to Irano- Touranian zone. Other species can be observed in other zones too.