Urban Forest Values: Integrating I-TreebModel and LiDAR Technology for comprehensive assessment of tree values in historic gardens

Recent advancements in forestry technologies, particularly the Handheld Mobile Laser Scanner (HMLS), have revolutionized urban forest planning by providing enhanced access to crucial tree structure features. LIDAR technology quickly captures detailed 3D models of trees, facilitating non-destructive biomass quantification in forestry, a feature highlighted by Pérez-Martín et al. (2021) in surveying monumental trees for green space inventories in preserving cultural landscapes. Urban forestry provides various benefits, contributing to the well-being of cities, their residents, and the environment. It plays a vital role in mitigating urban environmental challenges like high temperatures and CO2 levels, providing shading and enhancing air quality, as emphasized by Xie et al. (2023), who highlight the need for detailed urban coverage, down to individual trees, for comprehensive quantification of urban forest functions. I-Tree software is widely used in urban planning for estimating the ecosystem services of trees. Technologies like LiDAR enable the creation of high-resolution, 3D maps of tree structures, allowing for precise data on canopy density, height, and biomass. Additional biometric information, such as land cover, total tree height, crown size and LAI further enhances the model's accuracy on I-tree software. Recent advancements in LiDAR technologies allow for better-informed decision-making in urban planning and landscape design, maximizing the ecological benefits of urban green spaces (Sharma et al., 2024). Integrating technologies like LiDAR with ecosystem service assessment tools such as the i-Tree software allows for the evaluation and monetization of tree values. In this study, twelve monumental Ficus macrophylla subsp. columnaris trees were selected from various historical gardens in Palermo, Sicily. This tree characterized by expansive canopies and develops aerial prop roots from its branches, which thicken into additional trunks upon reaching the ground, providing extra support for canopy weight. Nondestructive field measurements with HMLS enabled detailed tree surveys. The I-Tree software used in this case study evaluates these urban monumental trees, quantifying tree benefits and the value of trees in urban areas through suitable software tools. The methodology extrapolates information on tree shape and overall conditions, creating 3D tree models to compute tree metric variables such as diameter at breast height, total height, crown basal area and wood volume. These provided biometric data on above-ground tree parts for monitoring tree health, growth, biomass, and carbon sequestration. This research addresses a notable gap in existing studies by using LiDAR and the i-Tree model to offer insights into sustainable urban forest ecosystems, especially for monumental trees and this species. The study's insights into carbon dynamics for each Ficus tree have significantly impacted decision-making by providing a data-driven framework for management of historic urban gardens to Palermo. If local community has been involved in future awareness-raising events, the process can lead to better decision-making by incorporating local knowledge into management preserving the benefits of historical landscapes. Engaging the community in decision-making can also foster a sense of ownership and responsibility, leading to more well-maintained tree resources (Kim et al., 2024). Integrating LiDAR technology with ecosystem services assessment tools maximizes urban monumental trees' benefits, enhancing decision-making for urban planners and researchers.