نشریه حفاظت و بهره برداری از منابع طبیعی
سال دوم شماره 1 (1392)

Due to the effect of atmospheric carbon absorption and sequestration، this study is investigated the effects of exclosure and grazing on carbon stoage by Astragalus gossypinus in the part of the cold semi-arid rangelands of Vezvar in Behshahr. After determination of key area، two sites consist of exclosure and grazed area was selected and plant and soil sampling was done by random-systematic method. Thus، 20 plants and 40 soil samples were collected totally. Conversion coefficient of enclosure rangeland (٪0. 78) was more than the grazed rangeland. Carbon stoage rates of roots with 19/9 kg/ha in exclosure area and grazed area with 8/33 kg/ha was more than the stem and leaf. Overall، the rate of carbon stoage in enclosure area with 1036467. 022 kg/ha was more than grazed area with 976082. 806 kg/ha and had not significant different. Investigation of carbon storage in soil showed that soil was stored more carbon to the plant biomass.

With regard to competition and economic conditions from pulp and paper plants، it is possible to provide emerging products and energy in wood and pulp industries، which may affect the main products and they will be converted into by-products. In future the world needs clean and renewable energy، which will be supplied، from biomass conclusively. In order to produce oxygen and carbon dioxide absorption، the tree plantation will be very useful on earth''s atmosphere. Wood waste and biomass are rich of carbon and hydrogen، and they can provide energy and different chemicals by the new techniques. The principles are similar to refineries and petrochemical plants called biorefinery، and biofuels and valuable chemicals such as methanol، Fischer-Tropsch Liquid (FTL) and Dimethyl Ether (DME) are produced. Usage of any kind of biomass، agricultural waste، and wood can be useful to produce a variety of wood products، wood composites، and also paper and paperboard. But the first step، in proper planning of forest is the silviculture by natural resource specialists. Concerning production of wood and paper، gasification is the best method of chemicals and energy production from wood wastes and black liquor. In the last years، researchers have developed new fields of fuel and energy from renewable sources، specifically biomass dramatically.

Miankaleh protected wetlandis the first international wetland، registered in Ramsar convention – 1975. This research، by study the climate condition، ecology، ecotourism and environmental strategies، trys to present strategic ways to better protection of this wetland. This wetland is a part of Miankaleh peninsula، located in the farthest south-east of Caspian sea with 24000 hectare square meter. This research recommends the best strategic protective way of: prevention of industrial، agricultural and sound pollution، prevention of industrialization and development، prevention of fishing and illegal hunting، organizing the livestock and fishing control، rules compilation، focusing the researches by a coordinated management and execution of a comprehensive plan via cauterization and participation of local residents by considering the tourism to protect the one of the most important ecological reserves in Iran.

Today، reuse recycled paper as one of the ways to supplying cellulosic raw materials for pulp and paper industry has been seriously considered. due to presence of contaminant such as adhesives and printing ink، optical and mechanical properties of recycled paper considerably reduced. However، using the method of deinking the properties of a drop can be prevented. On the other hand، because of the problems in this method، such as darkening of the pulp in an alkaline environment and increased effluent load to Cause limitations in using this method. Now، neutral deinking is as an alternative to alkaline deinking is introduced in the world. This paper will examine the advantages and limitations of this method. Overall، neutral deinking because of the reduced use of chemicals، resulting in significant savings in production costs and and the environment due to the elimination of sodium hydroxide، reduce COD and BOD values effluent mills. In addition، Reducing substances soluble dissolve in the paper in water process، resulting in increased yield and reduced yellowing of mechanical fibers pulp.

This research investigates and determines the preservation values of Babolsar beaches and measures the individual''s willingness to pay (WTP) for preservation it and also measures the effective variables on it based on contingent valuation (CV)، dichotomous choice (DC) and Heckman two-stage method. The needed data were obtained by personal interview through filling up questionnaires of 800 people who visited the beach in 2010. 74. 6 percent of visitors were ready to pay for preservation of these beaches. Mean willingness to pay for each visitor per year for preservation was 4387 rials in Babolsar beaches. Results showed that total preservation value of these beaches was more than 5418 million Rials and welfare situation of the studied beach and family size variables have the most effect on willingness to pay for preservation of the beach.

The western forests of Iran have high value regarding conservation، economy، society، recreational capabilities and ground water resources. These forests are gradually degraded and exchanged into the coppice forests. The present study aims to compare the regeneration status of undisturbed and disturbed oak stands. Based on this، four cemeteries were chosen in the Marivan town namely Gomarelang‚ Ebrahim abad، Kanisanan and Naie. These areas were considered as «less disturbed stands». Besides the area surrounding the given places was considered as «disturbed stands». The systematic random sampling method was used with the sample plots of 0. 15 ha. The data were analyzed using t-test in order to compare the means. The obtained results showed that there are significant differences between mean numbers of regeneration in the “less disturbed” and “disturbed” areas at 0. 05 confidence level. The obtained results also showed that conservation can play a key role for restoration of degraded areas.

Renewal volume of felled trees and separation of industrial and cordwood volumes are necessary in order to achieve real harvest rate and royalty interest. Therefore، various methods have been proposed for renewal volume of felled trees، namely traditional or one hundred percent method، regression method، statistical method، and 3p renewal volume method. The present paper aimed at introduction and determination of various methods for renewal volume of felled trees. In one hundred percent method، industrial volume of all trees is measured in a rather accurate manner; also، cordwood volume through an estimative calculation by a renewal volume expert. In regression method، 10% of felled trees are randomly selected and industrial and cordwood volumes are accurately measured; then، the relationship between standing wood volume and industrial and cordwood volumes are estimated and referred to other trees. In statistical method، trees are divided into four groups (i. e. beech، hornbeam، oak، and other species) and a diameter is assigned for each level which is mean industrial wood for each tree. Furthermore، a regression equation is defined for each group. In 3p renewal volume method، field operation is performed through accurate measurement of volume of industrial and cordwood trunks of the sample felled trees following selection of sample trees selected from tagged trees. The derived coefficients are referred to all felled trees. It was concluded that the 3p method owns more advantages than other methods.