Developing a Novel Martelloscope for Assessing Biodiversity and Growing Stock Volume with the aid of a Digital Twin

Developing a Novel Martelloscope for Assessing Biodiversity and Growing Stock Volume with the aid of a Digital Twin OG: BIOSEIFORTE BIOdiversity and Ecosystem Services in Forests and Territory Operational Groups in forestry and agroforestry sector play a key role in driving innovations at the EU level. These Groups disseminate results of OG’s activities and innovations to other EU countries within the project FOREST4EU (https://www.forest4eu.eu/) that is funded by the Horizon Europe programme. Operational group from Italy BIOSEIFORTE shared its innovation – devlopment of novel martelloscope for assessing biodiversity and growing stock volume with the aid of a digital trwin. An experimental marteloscope was used, where trees were surveyed through acquisition with the Geoslam ZEB Portable Laser Scanner system, which made it possible to recreate a 3D digital twin. Then, for each of the trees surveyed and forming part of the marteloscope, dendromicrohabitats were then obtained by means of traditional surveying, which made it possible to derive the Index of Potential Biodiversity (IBP) for each tree, in order to be able to introduce the quantification of biodiversity into the forest management plans and provide the users of the "gymnasium" an output in relation not only to productive interventions (wood growing stock) but also silvicultural interventions that take into account the biodivesity parameters. Operationally, in a 1hectare area of transitional beech stand, each individual tree (tree or sucker) was numbered, measured (crown insertion height and total height) and georeferenced, and its calculated volume and position data recorded in special software. In addition, each individual tree or stump was checked for the presence of dendrothelia (alterations, cavities, cracks in the stem and branches) that may constitute microhabitats for various plant and/or animal species and increase the ecosystem value of the stand in terms of biodiversit. Actually, the "martelloscope" is a portion of forest, of known surface area, in which for each tree present, various parameters have been defined: position (georeferencing), biometric characteristics (trunk diameter, height, volume, etc.), vegetative state, role within the community, ecological significance, etc. The martelloscope is therefore a permanent area where all trees are inventoried and constitutes a true "open-air gym" that can be used for the training of students and forestry technicians to simulate specific silvicultural interventions. It represents a potential tool for promoting dissemination on issues related to different types of forestry, as well as forest biodiversity conservation and climate change mitigation. The first European martelloscopes, originated in France since the 1990s, are now present in South Tyrol, Lombardy, Tuscany, and Apulia and used in various European projects, such as LIFE projects (GoProFor and SelPiBioLife) and Erasmus+ (Hammer) and also the BIOSEIFORETE OG in Italy. Thanks to the use of these open-air gyms, trainees can immediately obtain, also through the use of martelloscope-related software, data regarding the simulated intervention in quantitative terms, including graphs, in order to verify immediately the outcome of their choices, both in terms of management and economics. Generally, a martelloscope must have good accessibility, representativeness of the stand, long-term observation possibilities, and information availability on past interventions. All trees present must be marked with a numbered tag, while natural regeneration is assessed in visible internal areas. For the establishment of a martelloscope, it is very important to conduct a historical investigation on past interventions, aimed at establishing whether there have been previous disturbances such as windthrows, forest grazing, fires, etc. The operator, whether a student or forestry technician, based on field-collected data, can simulate a "virtual hammer blow," i.e., a practical simulation of the proposed interventions, and subsequently graphically Prepared by project FOREST4EU partner Latvian Logistics Association reproduce the stand before and after the intervention, calculating harvest intensity, structural changes in the stand, volume removed, etc. The main objective of the martelloscope is to "teach" various types of silvicultural interventions through: Analysis of forest structure (specific composition, density, basal area, volume, degree of tree cover, etc.); Selection of trees in a silvicultural intervention and learning of possible experimental methods; Awareness of how biodiversity and ecological values influence silvicultural choices. Through martelloscopes, it is possible not only to demonstrate practical silvicultural interventions but also to make comparisons between different interventions, observe the long-term effects of these choices, monitor regeneration, identify possible causes of decline, determine the evolution of balances related to competition phenomena, and calculate the value of the forest stand in relation to the cost-benefit ratio. Thanks to the development of technologies and digitization techniques aimed at generating 3D models from field measurements, it has been possible to reconstruct three-dimensional models of the area of interest, and so create digital martelloscope. In particular, terrestrial lidar systems collect large amounts of data ranging from tens of thousands to billions of 3D points to determine the space of a study area. In details, laser scanning, also known as lidar (Light Detection and Ranging), is a technology used for remote sensing to measure distances to objects or surfaces using laser pulses. It's widely used in various fields such as forestry, urban planning, archaeology, and environmental monitoring. In forestry, laser scanning plays a crucial role in forest inventory and management. Terrestrial laser scanners (TLS) are used to collect detailed data about the structure of forests, including he size and shape of trees, forest density, and ground terrain. This data is then used to create accurate 3D models of forested areas, which can help foresters make informed decisions about forest management, such as harvesting, conservation efforts, and assessing forest health. TLS systems are capable of collecting large amounts of data quickly and accurately, providing precise measurements of tree diameter, height, and canopy structure. This information is essential for assessing forest carbon stocks, biodiversity, and ecosystem health. Overall, laser scanning technology has revolutionized forestry practices by providing detailed and accurate data that was previously difficult or time-consuming to obtain. It has greatly improved our ability to understand and manage forest ecosystems sustainably. In forest survey activities, the Terrestrial Laser Scanner (TLS) can collect significant amounts of data rapidly, automatically, with centimetric resolutions. The purpose of using TLS is to improve the efficiency of data collection by replacing costly manual measurements; consequently, terrestrial laser scanners have been used to collect dendrometric variables such as DBH (diameter of plants at 1.30 m height above ground), tree height, and nearly exact plant position. Studies conducted by Berger et al. in 2014 demonstrate that tree diameter and height are characterized by an error of at least 5.6%, and manual measurement distortion affects the estimate by 26.4%. Therefore, using classical methods for volume and biomass estimation entails non-negligible random errors. The result generated by the use of laser scanners is a point cloud, which must be appropriately processed so that individual plants present in the point cloud can be identified through a process called segmentation. Segmentation refers to the extraction from a point cloud of the profile of each individual tree, based on which dendrometric variables are extracted. In addition to segmenting individual trees, another process to optimize in point cloud processing is Contacts Further information Information from Operational Group’s database FOREST4EU Project FOREST4EU Project [email protected] forest4eu.eu Funded by the European Union (Grant n. 101086216). Views and opinions expressed are however those of the authors only and do not necessarily reflect those of the European Union or REA. Neither the European Union nor the granting authority can be held responsible for them. partners: the classification of the ground surface, a crucial aspect for the entire process of forest digital twin processing. As highlighted in Zhong et al.'s 2017 study, models often fail due to the tilted orientation of trees, the presence of shrubs, and other occasionally present subjects. The use of new technologies is becoming more and more widespread in the analysis and monitoring of forest stands, and in particular forestry application of mobile LiDAR is becoming more widespread as it allows a considerable reduction in survey time and costs and returns good data accuracy, whereas up to now it has been used mainly in the building and infrastructure sector. Furthermore, the monitoring and quantification of biodiversity variation based on silvicultural choices made with the marteloscope is a useful added value for forest sustainable management, ecosystem services enhancement, as well as production aspects. Figure 1 – 3D Terrestrial Laser Scanner acquired Figure 2 – Segmentation of trees vertical view of the trees Figure 3Segmentation of the trees Horizontal view Francesca Giannetti, University of Florence. [email protected]