نشریه تحقیقات منابع طبیعی تجدید شونده
سال هفتم شماره 2 (پیاپی 24، تابستان 1395)

The current research is the first step on integral investigations to introduce suitable Eucalyptus provenance in order to use and development plantation with aim of increasing the wood production and import reduction. The study was carried out as randomized completely block design with six treatments (based on different provenances of Eucalyptus) and three replicates during 2008 to 2013. Accordingly, in each replicates 49 seedlings of each provenance were planted at 3 × 3 m spacing. Operations like crust breaking, weeding and weed removal, as well as qualitative and quantitative measures were performed each year until the end of the study. The results of the six-year study showed that E. camaldulensis 41-ch and E. macarthurii 169-sh provenance had the highest and lowest survival in Pars Abad area, 93.57% and 13.33%, respectively. Analysis of quantitative data indicated that the E. camaldulensis 41-ch, E.viminalis168- sh and E. viminalis 168-ch provenances of dbh and height growth 10.65, 9.55 and 9.47 cm respectively 50.8 cm and total height average 8.5, 7.10 and 6.7 respectively, had the best growth. Finally, the E. camaldulensis 41-ch, E.viminalis168-sh and E. viminalis 168-ch provenances, for the next phase of adaptability test were selected.

The present research analyzes the effect of fibers direction of joint parts in two directions (tangential directional and radial directional), the type of surface joint parts (joint type) in three models (gradient, step like, Persian freestanding), and the type of metal gasket of two shape (separate globular and one piece common) on the shear resistance of joints in wood trusses. In order to make the joints we used populous nigra of two kinds each one of them with the dimension of 5.1 × 5.1 × 30 centimeter. In order to connect the joints we used two standards ASTM D 1761 -88 R95 bolts with the diameter of 10 mm and we did not use any glue. Combining upcoming variables 12 treatments have been created and considering 4 repetition 48 truss joint samples created totally, and their Shear resistance have been evaluated with the mechanical examination device .According to the findings of the study the maximum resistance in all samples is of the gradient joint in radial direction with separate metal gasket. Interaction of fibers direction and the type of surface joint and also the interaction of two factors, the type of metal gasket and the type of surface connection is meaningful. Shear resistance increased in radial direction and common metal gasket and also among the types of surface joints, gradient joint has the maximum shear resistance.

In this study, physical and mechanical properties of MDF made of Recycled-Banknote and wood fibers were investigated. Urea-formaldehyde was used as binder in manufacturing of boards. The amount of resin was 10 and 12 percent. The boards were built of various mixtures of Recycled-Banknote and Wood fibers 100/0, 95/5, 90/10 and 85/15 %, respectively and press temperatures of 160 ° C and pressed for 20 min , mat moisture of 15% and board density of 0/7 g/cm 3 and pressure press were constant factors. Results indicated that increasing the amount of recycled banknote reduced MOR and internal bonding but decreased in the water absorption and thickness swelling. Specimens were prepared in compliance with EN-312 for physical and mechanical tests.

Application of probiotics as a way of growth in fish breeding is of a high potentiality. This study was conducted to evaluate the effect of probiotic protexin on the growth and survival of grass carp fry (ctenopharingodon idella). This experiment was conducted in a completely randomized design in four treatment and three replicates and 360 fry with average weight of 0.62±0.221 gr, (30 fry per aquarium) for 60 days. In treated group, Probiotic protexin was supplemented in aquaria water at three different levels of 1×10 5 , 2×10 5 and 3×10 5 cfu/ml every 4 days and the other three aquaria were added without any probiotic and treated as the control. The rate of feeding was on the base of the 5 percent of body weight for 3 times a day. All three experimental treatments showed significant increase (p<0.05) in final mean weight, weight gain percent, specific growth rate and feed coefficient efficiency with control treatment and among experimental treatments, The highest final mean weight (3.9±0.12), weight gain percent (520.7±13.01), specific growth rate (SGR) (3.0±0.04) and feed coefficient efficiency (79.6±3.16) were found in treatment received 3×105 cfu/ml. All three experimental treatments showed significant difference (p<0.05) in feed conversion ratio with control treatment and the best feed conversion ratio (1.2±0.04) was obtained in treatment received 3×105 cfu/ml. Also, maximum of survival percentage (100%) obtained in treatment of received 3×10 5 cfu/ml. The results indicated that the ability of probiotic protexin to influence the increase of growth performance and survival in grass carp fry is relatively high and the best effective doze is level of 3×10 5 cfu/ml.

This study was carried out to investigate the flora, life form and chorology of herbaceous plants in the protected and unprotected (7 years) areas in SHAFT, Guilan province. For this purpose 30 -1000 m2 circular sampling plots were selected by random- systematic method. Then, tree and shrub species were recorded and sampling of herbaceous species was done. In total, 57 species belong to 35 families and 55 species of 33 families were identified in protected and unprotected areas, respectively. In protected area, Rosaceae had the highest number of species, while, in unprotected areas the highest number belonged to Asteraceae. The study of chorology indicated that the species of euro- Siberian region were dominant in protected and unprotected areas by 12 and 14 species, respectively. hemicryptophytes was dominant life in protected (50.87%) and unprotected area (49%), whereas, Chamaephytes and Geophytes had the lowest number of species in these areas. Systematic planning and optimal utilization of plant cover for livestock grazing needs grazing management which can lead to continuous evaluation of vegetation cover based upon further studies on reconstruction in these ecosystems.

In this study, indices of some nutritional elements, namely calcium, magnesium, and sodium in the vegetative and flowering phonological stages for two species Agropyrum intermedium, Scariola orientalis as the dominant types of the studied area were measured. At least10 plants were randomly selected for each sample. Plant samples from1cm above the soil surface, including leaves and stems in the vegetative stage as well as leaves, stems, and flowers were clipped at the flowering stage. At each stage, three replicates of each sample (at least 10 plants per replication) and from each species 2 kilograms were clipped and then dried in laboratory conditions. The samples were then analyzed to determine the species metal ions. Duncan’s test using SAS software was run to analyze the data, which showed that in samples calcium, magnesium and sodium increased more significantly in the vegetative stage than in the flowering stage. The results indicated that determining the nutrient content of forage, detecting the nutrients imbalance, and timing the animals grazing can improve animal nutrition in rangelands and support valuable rangeland plants. Moreover, adding supplements to rangelands and forage can compensate for mineral elements deficiency.