## 1 Introduction  
Monumental trees are distinguished from ordinary trees by their physical and socio-cultural characteristics [1]. These trees, which are called the heritage of nature, can be used in scientific studies, increasing environmental awareness of people and tourism activities [2]. These trees are significant for several reasons, both ecological and cultural, and play an important role in local communities [3]. As a result, a lot of research studies have been conducted to estimate the value of monumental trees [4; 5; 6]. Large heritage trees are keystone ecological features that play a crucial role in maintaining the structure and dynamics of natural communities [7; 8; 9]. As monumental trees are very important for the physical and cultural environment, they have to be protected, and their value should be highlighted. The highlight of their value is also important because they can be used for sustainable tourism. Different monumental trees have been studied all over the world [10; 11; 12; 13; 14; 15; 16] and methods have been proposed for identifying these trees and estimating their value (e.g., [17]). The identification of these trees mainly relies on the trunk and the trunk rings. Olive trees have the special characteristic that the trunk has cavitations, distortion, and spiralization. The significance of monumental olive trees and their role in sustaining unique ecosystems, as emphasized by [18; 19], goes beyond their scientific value; these trees seem to embody a rich blend of scientific and cultural importance, serving as living monuments with ties to history, culture, traditions, and mythology in various regions. The value of monumental olive trees is also highlighted by [20]. Deciding whether an olive tree is monumental is crucial for several reasons. First, these trees should be protected due to their great ecological and cultural value. Secondly, in some countries, e.g., Greece, they receive extra economic support for their protection. Last but not least, these trees may be used for sustainable tourism since they attract the audience's interest. There are methods such as increment core sampling, radiocarbon dating (C14) and luminescence dating (OSL) that are used for the calculation of the age of olive trees. However, these methods are difficult to implement as they require specialized knowledge and equipment and stakeholders cannot have easy access to this information. Furthermore, there is no online system that can help estimate if an olive tree is monumental and its value. Given the above, it is our goal to implement an intelligent system that uses multi-criteria decision-making to evaluate olive trees and decide if they are monumental. The intelligent system will make the process easily accessible to all stakeholders who do not have an adequate background in criteria and multi-criteria decision-making. In response to these challenges, the goal of this paper is threefold. First, this paper aims at defining a way of evaluating and classifying the monumental olive trees and groves taking into consideration criteria that represent tangible and intangible criteria. Secondly, this methodology is implemented in a cross-platform application so that it can be easily accessible to large audiences. Thirdly, the methodology is based on the research project of [PERSON] et al. [21] which uses a combination of two multi-criteria decision-making theories and examines the combination of three different multi-criteria decision-making theories to improve the results. The theories that are employed in the methodology proposed in this paper are analytic hierarchy process (AHP), ViseKriterijumska Optimizacija I Kompromisno Resenje (VIKOR), and simple additive weighting (SAW) [22]. These theories are used for developing a forward-thinking approach to the evaluation and preservation of olive trees and groves. VIKOR, in combination with the SAW method, is employed to assess individual olive groves, providing a comprehensive analysis.