Journal of Renewable Natural Resources Research
Year:2011 | Volume:2 | Issue:2 (SERIAL NUMBER 4)|Papers Count:8

Fire is considered as one of the main destructive factors in forest ecosystems producing negative ecological, economic, and social outcomes. Identifying the factors contributing to break-out and spread is basic mechanism to combat fire and achieve control management. The research intends to identify the ecological factors influencing fire spread in forest ecosystems by using geographical information system at Kakareza area in Lorestan. After conducting basic studies, homogenous environmental units were produced and divided into four classes by using multi criteria evaluation method. The condition of regions having already caught fire was studied by inventory. The data were analyzed by using GIS and AHP. The results of this study showed that vegetation and moisture in fuel materials are the main factors affecting fire spread in forest ecosystem.

The feeding habit of Pennahia anea was studied in the north-west of Oman Sea by collecting 188 specimens during years 2010-2011. The samples were collected seasonally with midwater trawls during lantern fish fishing. Vacuity Index (VI), Fullness Index (FI), Gastro-Somatic Index (GaSI) and frequency percentage of different food items were also studied. Of total stomachs, 40 stomachs were full or semi-full and the other 148 were empty. GaSI Index average was 1.1 for the total year. The mean Vacuity Index was calculated 78.7% and amount of Food Preference Index were estimated as: Fishes (92.5%), Crustacean (22.5%) and Molluscs (5.0%). b=3.12 shows isometric growth in the P. anea. It was concluded that P. anea is a relatively abstemious species and its main food was Fishes and minor foods was Crustacean

The goal of this research is to study the ultrasound wave parameters such as velocity and attenuation in Picea abies species. To that end, two varieties of this species were selected For Ujavbit Woods in Kelardasht, Maznadarn Province. To prepare samples, discs in 5 cm thickness were prepared in the three types of with bark, without bark and defected (handmade hole) to be used in measuring ultrasound wave parameters. In this research, the measurement technique used was direct contact with 55 KHz frequency. The results of the test showed that the tree bark increases wave attenuation coefficient intensively while it has no significant effects on wave velocity. The result also suggested that the defects (artificial hole) in Picea abies species disc had the highest effects on ultrasound wave velocity parameters and decreased it sharply; however, it has no significant effects on wave attenuation coefficient.

In this experiment, the fingerlings of grass carp reared under natural feeding of the pond were allowed to observe carp attacks on fully floating (pieces of bread) and sinking food (laboratory –made pellet). The performance and feeding starting times were then compared among carp-exposed or carp-observer grass carp that could see the food directly with the demonstrators’ foraging activity and naïve grass carp groups that couldn't see the demonstrators’ (common carp) feeding activity. The carp-exposed and carp-observer groups of grass carp were better at feeding reaction (start time) than naïve fish when they fed on two novel fully floating and sinking food. When they fed on floating bread, 80% of the chambers of grass carp with carp in compare with 53% of the chambers with only naïve grass showed starting taking food for the duration of 5 days. When they fed on sinking pellets, 65% of the carp - observer grass carp in the tanks compared with 20% of the chambers with the naïve grass carps, showed taking the diet for the duration of 5 days. More carp-exposed grass carp learned taking novel floating diet during 10 days experimental period and the observer grass carp in the experimental tanks with sinking novel diet showed catching pellets 48 hour before the naïve grass carp groups. The fingerlings of carp-exposed and carp-observing grass carp were capable of direct observational learning in their feeding behavior.

Volume estimation of the tree is considered as one of the important sections of the forest growth prediction and production. So far, many relationships such as: Newton, Smalian, Pressler and Huber have been used to estimate the volume of the trees that all these relationships require measurements of diameters at certain heights that are difficult to obtain on standing trees especially when diameter measurements have to be taken several meters above ground. In this study, an attempt was made to implement the new technology of Artificial Intelligence (AI), and one of its subsets as Artificial Neural Networks (ANN), since there was no primary assumption about the distribution of data, and for industrial bole volume estimation of 101 trees of trees marked of Research and Educational Forest of Tarbiat Modares University. For this purpose, DBH, diameter at stump height, end diameter stem, stem height and total tree height were measured with high accuracy. Two neural network models, multi-layer perception (MLP) and radial basis function (RBF), were developed to estimate bole volume. The results indicated that the radial basis function neural network was more accurate in bole volume estimation than the multi-layer perception neural network. Comparing evaluation criteria for ANN showed that MLP and RBF neural networks had RMSE value 1.18 and 1.05, respectively.

Land use change has been imposed by increase of population on natural ecosystem. Soil, as a bed of plants, is one of the important components of ecosystems, and is affected by land use change. It is essential for a better management to be aware of soil properties alteration in different land uses. Therefore, in order to achieve that awareness, this study was conducted in Peshert- Kiasar. Systematic sampling was conducted in three neighboring sites of forest, rangeland and agricultural land. 49 soil samples from the depth of 0-30 cm were collected from each site. Then, soil properties including pH, EC, total nitrogen, organic carbon, soil texture (percentage of sand, silt and clay), soil moisture were measured. ANOVA with Duncan test (p<0.01) using SPSS software was used in order to have a comparison of soil properties among different land uses. The results showed that carbon and nitrogen had relatively more and pH less alterations in the study area. Also, soil properties show significant different among various land uses.

In this research, fractionation of OCC pulp was investigated. Also, the effect of refined long fiber fraction of OCC pulp blended with virgin kraft pulp on the strength of pulp was studied. The results showed that mixing the refined long fiber fraction of OCC pulp with virgin kraft pulp increased the strength of pulp. Using fiber classification method and refining the long fiber fraction of OCC pulp showed that handsheets containing 30-50 percent refined long fiber fraction of OCC pulp showed higher mechanical strengths comparing to virgin kraft pulp. Also, in comparison with virgin kraft pulp, mixing the short fiber fraction of OCC pulp with virgin kraft pulp decreased porosity and increased air permeability of hand sheets.

The grass carp (Ctenopharyngodon idella) is mainly used for the food production and aquatic weeds control. The aim of this study was to assess the feeding preference of grass carp by 3 submerged plants including curly pondweed (Potamogeton crispus), Eurasian watermilfoil (Myriophyllum spicatum) and coontail (Ceratophyllum demersum), 2 free floating plants including water fern (Azolla filiculoides) and duck weed (Lemna minor) and water silk (Spirogyra sp.). The research was carried out at the Shahid Ansari Fish Reproduction and Breeding Center in 2011. Vegetative organs of experimental plants were collected from the Anzali lagoon and planted in the fish aquaculture. Four weeks later (on 5, May 2011), the grass carp by average weight of 20 g were released in the pools and monthly weighted by the end of experiment. The results showed significant (p<0.001) increase of grass carp weight in the eurasian watermilfoil, duck weed and water silk submerged plants treatments compared to the other treatments. The maximum weight and length of grass carp were observed in duck weed (380 g, 31 cm), eurasian watermilfoil (365 g, 29 cm) and water silk (350 g, 28 cm). The maximum fat percent were also measured on eurasian watermilfoil, water silk and duck weed with 7.21, 7.15 and 7.08%, respectively. Besides the maximum protein content were measured in eurasian watermilfoil, water silk and duck weed treatments with 16.02, 15.88 and 15.68%, respectively.