جستجوی مقالات مرتبط با کلیدواژه "seedling survival" در نشریات گروه "جنگلداری"

In dry areas, the lack of rainfall, inappropriate seasonal distribution, and high evaporation and transpiration, and on the other hand, high water supply costs, cause the loss of seedlings, especially in the critical period of establishment. In the present study, the effects of different moisture storage treatments on the quantitative and qualitative growth of Cercis siliguastrum L., Celtis caucasica Wild., Elaeagnus angustifolia L. and Amygdalus scoparia Spach plantations were studied in the Semnan University. This experiment was conducted in a completely randomized design with five treatments: i) soil texture modification, ii) use of hydrogels, iii) zeolites and iv) straw with crushed stone and v) control (natural soil of region) with five replications and totally 300 seedlings of the species. The height, collar and crown diameter, number and length of lateral branches were measured at the beginning and the end of the growth period and survival rate of all seedlings were recorded at the end of growing period.  In Cercis siliguastrum, the highest growth of collar diameter, crown and length of lateral branches were measured under straw treatment.. In Amygdalus scoparia, the highest quantitative growth values were observed in straw treatment. In Elaeagnus angustifolia and Celtis caucasica , different treatments had no significant effects on growth parameters. Different storage treatments had no effect of survival of investigated species. The lowest survival rate (with a range of 80-88%) was related to Amygdalus scoparia seedling and no significant difference was observed in this factor amongst other species. The type and efficiency of moisture storage methods are different according to the type of species used, the straw and crushed stone treatment was effective in the growth of Celtis caucasica and Amygdalus scoparia seedlings. In contrast, Celtis caucasica had the highest growth in the natural soil. On the other hand, none of the investigated moisture storage treatments had no effect on the vegetative characteristics of Elaeagnus angustifolia seedlings. Furthermore, the use of hydrogel and zeolite had no positive effect on the growth and establishment of the investigated species.

This study was carried out in the researching forest of the UPM University of Malaysia. In order to enrichment the forest artificially and in four different ways, make artificial gap in four 1 ha (100×100) plot. 9 micro plots 10m×10m made in 2 plots and 5 micro plots 10m×10m and 20m×20m in 2 other plots, totally 28 micro plots. In these micro plots was planted far from others in 2.5m×2.5m, seedlings of 3 species of Shorea assamica, Shorea platyclados, and Mersava anisoptera, (totally 812 seedlings). Species, number, diameter, length of stem with out branches, length, diameters of crown, survival percentage of seedlings and light intensity in each micro plot was recorded. The light intensity classified in 3 classes (Class 3: 17% - 23%, Class 2: 10% - 17%, and Class 1: 4% - 10%). Results showed that seedlings which are in Class 2 of light have more Height and Diameter growth and have more Chances of survival. M. anisoptera had the highest survival rate, and S. assamic had the less. M. anisoptera had the highest diameter growth and S. platyclados had the less. In Class 2 and 3 the diameter growth was more than in Class 1. S. platyclados had the highest growth rate in Class 2, and S. assamic had the fewer rates in Class 1. The S. platyclados had the highest crown diameter, and the S. assamica had the less. Crown diameter in Class 2 and 3 are the same and was the maximum rate, and in Class 1 had the minimum rate. M. anisoptera had maximum stem length and S. assamica had minimum and in different Light Classes had non-significant. Interaction between species and Light class had non-significant effect on height and diameter growth and had significant effect on crown diameter and stem length.