Co-authors: Matheus Roberto da Silva, CMPC Forestry Operations Coordinator; Lucas Zancan Pissinin, CMPC Forestry Operations Coordinator; and And Bernardo Neutzling Czermainski, Operational Excellence Analyst at CMPC.

The forestry sector is very hot in Brazil and this is evidenced by the productive industrial and forestry investments made by companies in the segment in recent years.

According to the Brazilian Tree Industry, total productive investment in 2021 was almost 20% higher than in 2020, totaling 15.1 billion reais. Of this amount, the highest amounts were allocated to expanding production capacity, which consequently promotes an increase in the forestry base.

The evolution of the business and the expansion of the forest base create a great demand for resources and manpower, which are increasingly limited in the country, making it a challenge to hire new employees and comply with labor and environmental legislation.

To solve this challenge, there is a real need for advances in the development of mechanization and automation of silvicultural activities, which must be connected to several factors, among which innovation and sustainability are indispensable pillars.

Given this situation, the incorporation of new technologies, such as the use of drones , is a strategic and fundamentally important tool. It replaces some manual and mechanized activities, mainly herbicide applications, becoming an alternative to scenarios of legal restrictions, reducing people's exposure to chemical products, minimizing safety risks and providing lower water consumption.

In addition, it becomes a differential in maintaining the technical prescription, that is, carrying out the operation in the necessary period and quality, without impacting on the increase in costs. Currently, there are several types of drones adapted for herbicide spraying. However, it is correct to use those that are designed for this purpose and that meet the general requirements for the use of unmanned aircraft detailed in the Brazilian special civil aviation regulation of the National Civil Aviation Agency.

The regulation of drones is still a very complex territory, however the changes in resolution 710 of March 31, 2023 defined that Remotely Piloted Aircraft Systems , during the application of agrochemicals and adjuvants over uninhabited areas and up to 400 feet, are classified as class 3 regardless of maximum takeoff weight, provided operating in visual line of sight or extended visual line of sight . This review showed that laws are following the new reality and advances in technology; it also enabled the use of drones with tanks with greater volumetric capacities, improving the productivity of operations.

At CMPC Brasil, drones are used to carry out two main activities, pre-planting chemical weeding with application of pre -emergent and post-emergent herbicides in conjunction and application of pre -emergents after planting. In carrying out these operations, application technology concepts and environmental assumptions linked to appropriate weather conditions are observed, such as wind speed and relative air humidity, in order to ensure that the application is well distributed, with good penetration and good coverage on targets.

Interconnected with this, it is important to emphasize that the use of drones , by itself, does not reach the objectives and gaps of the activity. We have opportunities for co-evolution in several aspects that can and should boost the use of the tool in the short term, such as the development of products that allow its application and effectiveness with restrictions on water consumption and also products with selectivity to eucalyptus and a greater spectrum of control of various existing weeds; in addition to the improvement of the spray nozzles, allowing for an increase in swaths and coverage. We can also evolve into batteries with greater capacity and recharge speed, drones that return to the base for self-supply and self-recharge in order to reduce the number of people involved in the operation. However, as we make progress in all these aspects, we cannot forget the training of people and specialized labor, an essential link to link all of this together.

Other possibilities are associated with the elimination of eucalyptus shoots and the distribution of ant baits with a drone . The first requires operational improvement to ensure effective control and the second runs into legislative restrictions for its implementation. In short, as we have seen, there are countless current applications and potential for the use of drones in forestry, as it opens up promising paths for more efficient and sustainable management. We cannot, however, stop imagining and seeking alternatives for the future.

In this context, the use of drones for the application of agrochemicals in forestry, from pre-planting activities to cultural practices, must be structured within a future scenario of 100% mechanized forestry. Operating systems with standardized native telemetry should be made available, from soil preparation, planting, irrigation and fertilization (already present on the market and in an advanced stage of development) with mechanized or automated cultural practices, including drones .

Another not too distant future that we can imagine and build at an operational level is the integration of information between different mechanized operations through the advancement of the internet of things, artificial intelligence and other advances in the processing of large volumes of data. Why can't we generate a flight plan for the pre-emergent herbicide application in row-by-row rows, using the seedling georeferencing information already present in some mechanized planting systems? Or, we can operationally enable the integration of vegetation cover mapping results (Normalized Difference Vegetation Index) of the infesting vegetation in the drones themselves, generating a flight plan with application at variable rates, with different volumes of syrup depending on the geolocated infestation in the fields?

Ultimately, the flight into the future of 100% mechanized and automated forestry is taking place as technology advances and regulations adjust. And drones in forestry will be part of this story, becoming an extremely valuable tool.