Determination of an age in a particular tree species can be considered as a vital factor in forest management. In this research we have introduced a novel scheme to determine the accurate age of the tree species in Sri Lanka. This is initially developed for the tree species called‘Hora’ (Dipterocarpus zeylanicus ) in wet zone of Sri Lanka. Here the core samples are extracted and further analyzed by means of the different image processing techniques such as Gaussian kernel blurring, use of Sobel filters, double threshold analysis ,Hough line transformation and etc. The operations such as rescaling, slicing and measuring are also used in line with image processing techniques to achieve the desired results. Ultimately a Graphical user interface (GUI) is developed to cater for the user requirements in a user friendly envi-ronment. It has been found that the average growth ring identification accuracy of the proposed system is 93% and the overall average accuracy of detecting the age is 81%. Ultimately the proposed system will provide an insight and contributes to the forestry related activities and researches in Sri Lanka.