The Lun Olive orchard complex is located on the far north of the extended stretch of the island of Pag. Olive trees at this area are visually estimated by age groups on those trees that are only several years old, more centuries-old trees, to trees older than more than a thousand years. The trees of different ages are mutually mixed together and grow scatteredon the rocky ground. The total area of this complex is 400 ha and the number of trees is estimated to about 80,000. From the total area under the management of the Lun olive-growing cooperative Lun is about 50 hectares, and 20 hectares is protected since 1963 as nature reserve The uniqueness of the Lun olives is manifested in their emergence from the seed or by the generative reproduction method by which the olive is naturally propagated without the influence of man (Benčić 2015). Secondly, there is the visual effect of old individual trees great age manifested in their specific and rare form. The method used to determine the age of the selected trees from the Lunjski Olive complex, which was applied in this research, is based on taking the increment cores. In addition to this method, in order to better understand and define the way of tree ring formation and tree ring boundaries a year-long tree growth was monitored using dendromet bands and special Trephor tool which enables taking small cores and monitoring tree ring anatomy formation. The results of this one-year growth increase have shown that the average ring width ranges from 1.34 to 5.06mm, and is largely related to the amount and the annual rainfall distribution. The age of trees A1 and A2 of 13 years was determined by the method of taking the increment cores, which was confirmed by the owner of the olive trees with the year of planting. The same method determined the number of tree rings for trees A3 and A4 and which is 71 years for tree A3 and 80 years for tree A4. Both trees were previously visually estimated at age of about 100 years. In the case of trees A5 and A6 that were visually estimated for the age of more than 1500 years it was impossible to determine the absolute age because the large part of the trunk central part was rotten and asymmetrical with large number of poorly defined tree rings.