###### Abstract
In this light, the successful monitoring and evaluation of ecosystem and species health, entailing the timely identification of fungal pathogen presence through early warning signals and rapid diagnostic procedures, alongside the quantification of disturbances at the ecosystem, species, and population levels, present significant challenges. Given the pivotal role of this information in formulating effective strategies for the protection and conservation of trees, various plant phenotypic methods [47], directly or indirectly related to the eco-physiology of tree species, have been developed and implemented. In fact, significant progress has been made in the development of efficient monitoring techniques, encompassing both destructive and non-destructive approaches that utilize diverse tools, categorized based on their measurement speed, resolution, and accuracy, for the purposes of (a) screening, (b) evaluation, and (c) diagnostic assessments [48; 49]. When considering non-invasive techniques while simultaneously accounting for factors such as sensitivity, accuracy, cost, time requirements, and operational simplicity [50], infrared thermography (IRT) emerges as a prominent technique among the plethora of available options such as static bending and transverse vibration techniques [51], ground-penetrating radar methods [52], sonic/ultrasonic tomography [53], and electrical resistivity tomography [54]. In the field of ecology, IRT has found widespread application [55; 56; 57], demonstrating its effectiveness in diverse fields such as detecting pests in forested areas [58; 59], monitoring crop vegetation [60; 61], identifying water stress [62; 63; 64], and diagnosing fungal infestations [65; 66]. Regarding tree health, while the application of IRT is relatively recent, its use is rapidly expanding [67; 68; 69; 70; 71; 72; 73]. By integrating non-invasive monitoring techniques, such as IRT, with established forestry practices and metrics for assessing plant structural and functional traits, it appears that disturbances at multiple levels can be rapidly detected [73]. However, despite the individual utilization of IRT in assessing tree health in different systems, there has been a lack of a unified framework that incorporates these distinct systems. Therefore, our study aims to bridge this gap and provide a comprehensive approach that integrates IRT with species-specific biophysical traits to effectively evaluate tree health and identify potential disturbances across various environments. By incorporating fundamental biophysical traits of trees, such as height, diameter, crown area, and leaf area, into this non-invasive technique, we anticipate that our approach will yield valuable insights. This integration will enable us to derive a set of indices that accurately depict the overall condition of trees. Through the application of such a unified framework, we aim to enhance our understanding of tree health and contribute to the development of effective management and conservation strategies for trees in different ecological settings. To accomplish this, we collected thermal and phenotypic information, with particular emphasis on productivity, from five prevalent tree species distributed across urban, agricultural, and forest settings, within a typical Mediterranean environment. Our objectives were to (a) examine thermal pattern variations within and among the five tree species as well as among trees classified into different categories based on the presence or absence of defects, (b) investigate the relationships between the phenotypic traits of trees and their trunk thermal indices, (c) quantify the influence of the trunk thermal indices and phenotypic traits on leaf area index (LAI) (as an indicator of tree productivity), and (d) elucidate the presence of tree defects and fungal pathogens through these indices.