Forests in danger? Drones can come to the rescue
The FRESh LIFE European project is studying new drone remote surveying techniques for monitoring these fragile and important ecosystems. The drones will also be exhibited at the Night of Researchers 2017 in Florence.
Forests are complex systems that provide a wide range of services for the benefit of the ecosystem: from wood and timber production to the assimilation of the main greenhouse gas (CO2). Forests contribute to our health by removing pollutants from the air, protecting us from landslides and avalanches, allowing us to improve the quality of our lives as they are places to spend our free time. They are also the terrestrial habitats with the highest level of biodiversity.
Sustainable management of a forest means exploiting its precious advantages by conserving this potential unchanged for future generations. For this reason, forests must be periodically registered for assessment, just as it is for the human population, to detect the changes in progress.
But getting information on forests through traditional land-based measures is a long, arduous job, as well as extremely expensive, given the enormous extension of our forests: the population of trees in our territory is estimated at about 12 billion individuals.
In this context, new remote sensing technologies open up new scenarios that were unfathomable only ten years ago.
The European project FRESh LIFE — Demonstrating Remote Sensing Integration in Sustainable Forest Management (LIFE14 / IT000414) — aims to demonstrate the use of remote pilot systems (SAPRs), better known as drones, to acquire support information for a sustainable forest management.
Four demonstration forest areas were selected in three regions for a total of about 1,000 hectares between Tuscany, Lazio and Molise for the development of the project. In each area, detailed ground surveys were carried out to assess the quality of the drones’ remote sensing estimates.
The two drones we used have very different characteristics one from the other.
The first is a large multi-rotor with eight engines and has a flying autonomy of about 20 minutes. Developed by the spin-off OBEN, on a day-to-day operation with several multi-battery flights, the eighth-rotor allows data to be captured on a total surface of between 20 and 50 hectares depending on the accessibility and and orography of the area. This drone is equipped with a laser scanner (LiDAR — Light Detection And Ranging) that enables us to obtain clouds of georeferenced points with a density around 50 points per square meter. LiDAR data permits a complete and detailed three-dimensional reconstruction of detected surfaces.
The second drone (called eBee of the SenseFly) is instead a fixed wing unit, that is, a small aircraft equipped with a camera with optical sensors capable of capturing wavelengths of visible and near-infrared light, with very high definition and ability to detect details up to a few inches.
This drone has a 45-minute flight time and, with enough battery changes, it can survey surfaces up to a thousand hectares in one day.
Both drones are essentially robots able to fly independently. Once the mission is defined and the take-off takes place, they can operate and land once they have finished, optimizing battery usage and the quality of captured data even under variable weather conditions.
The collected data allows researchers to estimate a number of indicators relating to the type of forest, its composition, and the state of health that are essential to guide sustainable forest management choices.