The Influence of Initial Spacing on Early Mortality and Growth in the Casuarina Plantations at Balukhand, Puri Division, Orissa

An investigation, comprising 54 sample plots, was started at Balukhand in 1941, with a view to determining the influence of initial spacing, subsequent thinning treatment and rotation age on volume production and financial returns from plantation Casuarina in the locality. Examination of the data collected till the age of 7 years, by which time no thinning treatment had been given to any of the plots, reveals that initial espacement has a clear effect on mortality rate, diameter development and production of Basal area during this phase of the crops' life. Three initial spacings, viz., 6, 9 and 12 feet square have been under trial. Increase in planting espacement cuts down mortality rate and accelerates diameter growth. But while the difference between 6 feet spacing on the one hand, and 9 and 12 feet spacings on the other, is highly significant, that between the latter two alone is not significant at the 5% probability level. Basal area production shows an exactly opposite trend. The drop in this parameter from 6 feet to 9 feet spacing is not significant. While that from either of these two to the 12 feet spacing has turned out to be highly significant. Statistical and graphical analyses of the data indicate that the 9 feet square espacement probably provides the crop optimum conditions of growth till the age of 7 years.