A Comparison of Random-Systematic methods to Estimate seedling mortality in Aeolian Dust sources

This study was conducted in the aeolian dust sources of the southeast of Ahvaz to determine the best survival method for planted seedlings. Full calipering method (%100 inventory) used for 16.2 hectares planted seedling. Sampling sample-line methods were performed with a fixed number of trees (in intensities of 10 and 13%) and a sample plot with a fixed area in five sampling networks with different dimensions of the sample plot and three intensities of 5, 10, and 13%. Then, a one-sample t-test was used to compare the mean of each method with the percentage of survival in the %100 sampled method at a significance level of %95. According to the results of %100 statistics, the survival rate of seedlings planted in the field was %72.9. The results indicated that the sample-line method with an intensity of 13% (average of 80 holes per sample line) had the closest estimate (71.8%) to the percentage of real survival. Also, the 30×30 m sample plot method with 13% intensity and 70×100 m network dimensions showed the closest estimate (72.1%) to the real survival percentage. Results of the single sample t-test showed that the sample-line method with sampling intensity below 13% was not significantly different from the control. Among the studied methods, only methods E (10% fixed area with 90 ×100 grid dimensions) and G (13% fixed area with 90×100 grid dimensions) differed from the control. The lowest percentage of standard errors belonged to H (13% fixed area with 70×100 grid dimensions) and I (13% fixed area with 35×100 grid dimensions). The lowest percentage of standard errors belonged to H (13% fixed area with 70×100 grid dimensions) and I (13% fixed area with 35×100 grid dimensions). Totally, this study showed, the area sampling method is superior to the sample-line methods estimate the percentage of survival in the planted areas, and in general. It is suggested to use the H method (fixed area 13% with 70×100 grid dimensions) in forestry areas.