Towards Sustainable Futures in Tree Assessment using Ground Penetrating Radar: Insights, Developments and Novel Perspectives

The global impact of diseases and environmental pressures on trees and forests has resulted in the decay and loss of a significant portion of the Earth’s natural heritage. Responding to this challenge, Ground Penetrating Radar (GPR), a well-established and reliable non-destructive testing (NDT) method, emerges as a fundamental assessment technique with vast potential. Its efficacy spans various domains, from Earth sciences to engineering, making GPR uniquely suited for forestry applications and offering a sustainable and non-invasive alternative to destructive methods like coring. Within forestry applications, GPR assumes a critical role in optimising economic expenditure for tree maintenance while simultaneously enhancing public safety. Swift and reliable detection of subsurface anomalies make GPR essential in safeguarding natural heritage and facilitating early identification of tree decay, ultimately supporting effective tree disease control. The present work explores the extension of GPR's capabilities to evaluate critical parameters in tree health, focusing on the assessment of root systems and the identification of potential structural weaknesses within tree trunks. The study introduces a series of recent experimental-based and theoretical models, each contributing to the understanding and enhancement of tree assessment. These models refine the interpretation of intricate reflection patterns, providing a refined understanding of tree trunk conditions. Additionally, models for the early detection of decays and cavities in tree trunks are presented, offering valuable insights into the internal structure of trees and enhancing the sensitivity and precision of GPR for proactive tree health management. In terms of assessing and monitoring tree roots, the study introduces methodologies designed to enhance the understanding of below-ground ecosystems. Developed algorithms for root detection and tracking, along with methodologies for estimating root mass density, offer insights into growth patterns and contribute to sustainable tree management practices. Furthermore, recent methodologies focus on understanding interconnections within tree root systems and the surrounding environment, identifying buried structures within the root system, addressing unique challenges faced by street trees in urban environments, refining the analysis of tree root systems using frequency spectrum-based processing, and integrating artificial intelligence for automatic recognition to enhance the efficiency of root system assessment. Finally, unique case studies are presented, showcasing the methodology, survey planning, and site procedures. These case studies add depth to the exploration, reflecting the practical application of the research in diverse and challenging scenarios.