مجموعه چکیده انگلیسی مقالات

Determination of beech (Fagus orientalis Lipsky) seeding cycle in Ziarat Forest

 
Abstract
The trail was conducted at ZiaratForest (Longitude: 54º 25´ East, Latitude: 36º 43´ North, altitude: 650-2350. asl) of Caspian region of Iran in order to identify the seedling cycle of F. orientalis.
Twenty seven dominant beech trees were selected for quantitative and qualitative measurment. After soil and ground cover sampling and tree measurment, the trees were cut down and a disc sample was taken from each tree''''s stump. The discs were analyzed to study the annual rings. The results showed that:
1-Fagus orientalis has two seeding types, heavy and light.
2- The minimum age of seeding is about 49 year when is often associated with light seeding.
3- The heavy seeding begin at age of 57 year.
4- At a same site, different seeding cycles were observed during the living period.
5- The light and the heavy seeding repeat at 2-6 and 3-27 year period, respectively.
6- Natural regeneration depends on the light seeding cycles due to their frequent occurance.
7- There was a relationship between the averag decerese of annual ring growth rate and seeding types as follows:
a. If decrease of annual ring growth rate is more than 1mm, there will be a heavy seeding cycle.
b. If decrease of annual ring growth rate is between 1mm and 0.31mm, then there will be alight seeding cycle.
C. If decrease of annual ring growth rate is less than 0.31mm, there will not be a seeding cycle.
 
Key words: Forest, beech, Fagus orientalis, seeding cycle, growth, age.
 
Effects of eucalypt plantation on understory plant cover and some soil parameters in comparison to next natural forest in Astara of Iran

 
Abstract
About 30 years ago, a eucalypt species trial was conducted in Caspian coastal forest of Iran at Astara, after clear felling the natural Querco – Carpinetum forest type. The aim of the study was investigation the effect eucalypt plantation on understory plant cover component and soil properties .For this purpose, the understory species and their frequency was determined in both eucalyptus plantation and next natural forest. The Sorenson method was used to study the heterogeneity homogeneity of plant communities .Furthermore, the soil Na⁺, K⁺, organic matter and electrical conductivity (EC) were measured. Results showed that there was only 54% homogeneity between the understory plant cover of two sites according to Sorenson index that indicated the significant effects of Eucalypt plantation on kind and frequency of species. The amounts of Na⁺, K⁺, organic matter and EC was less in eucalypt plantation site  than the natural forest site.
The results showed that there was only 54% homogeneity between the understory plant cover of the two sites according to Sorenson Index and significant effect of eucalypt plantation on flora. The amount of Na⁺, K⁺, EC and organic matter in eucalypt plantation site was less than the natural forest site. It was concluded that eucalypt plantation on natural forest sites should be limited due to its significant effects on sol and flora.
 
Key words: Forestation, Eucalyptus, natural forest, Plant understory.
 
Effects of using Aquasorb Polymer on irrigation of Pinus eldarica, Olea europea and Atriplex canescens
 

Abstract
This experiment was carried out in 2001 in order to determine the effect of aquasorb polymer on irrigation of three plant species in Hossein Abad Station of Sand Stabilization of Qom province.
The Factorial statistical method under Randomized compete blocks design whit three replicates was used. There were two Factors: species (Atriplex canescens, Pinus eldarica Medw. and Olea europea L.) and Aquasorb polymer (0.0%, 2.0%, 4.0% with irrigation interval three times were than normal interval) and control irrigation with normal interval). The variables were: Soil water content (%) before and after irrigation (at depths of 25 and 50 cm) and survival % one, three and six months after plating. The ANOVA and Duncan tests were used to analyze the data.
The results showed that there were significant differences (p