Remotely piloted aircraft systems and forests: a global state of the art and future challenges

Abstract

Remotely piloted aircraft system (RPAS) platforms are able to optimize the process of acquiring aerial images and improve the quality of the products generated in terms of spatial and temporal resolution. The exponential advance of the use of RPAS platforms in forestry, especially from the year 2010, is noteworthy. In this review, we present the global state of the art of the development and applications of RPAS technology in forestry, structured from a systematic review. Our results reveal a trend towards the use of multirotor RPAS platforms compared with fixed-wing platforms and that sensors that register in the visible spectral range are still the most widely used. More recent research has shown applications geared especially for areas such as forest inventory, with many innovations based on the detection of individual trees. Special focus has also been given to new alternatives for pest and disease mapping and phenological phenomena that occur at short intervals, as well as the monitoring of fires and postharvest areas. Therefore, there is a great potential for the use of RPAS platforms in a wide range of forest applications, whether linked to the productive sector or to the conservation of biodiversity, with great advances for spatiotemporal forest monitoring and expectations of further progress for the coming years.

Capturing hedgerow structure and flowering abundance with UAV remote sensing

“…UAV surveys can provide information on their condition and can potentially be used to investigate whether legal requirements are met. The SfM workflow can also be readily used to characterize farm woodland structure as evidenced by a number of forestry studies (Eugenio et al., 2020), whereas flower detection and mapping can be extended to wildflower margins that tend to be implemented to enhance pest control and pollination services in adjacent fields. Although clear enhancements to pest control are evident, effects on crop pollination can be more variable, with perennial and older flower strips with higher flowering plant diversity enhancing pollination more effectively (Albrecht et al., 2020), in addition to benefiting rare pollinator species and pollinator diversity (Sutter et al., 2017).…”

“…Unmanned aerial vehicles (UAVs) equipped with miniaturized sensors can potentially fill this niche. However, although there is an increasing number of publications that demonstrate the potential of UAV remote sensing for vegetation surveys (Eugenio et al., 2020; Radoglou‐Grammatikis et al., 2020; Smigaj et al., 2019), such studies have yet to be performed on hedgerows. Therefore, this study aims to investigate whether UAV remote sensing can be used effectively for performing hedgerow condition surveys, focusing on capturing hedgerow structure and flowering abundance.…”

Battery consumption estimation methodology for electric unmanned aerial systems

“…As ESC efficiency factor is a function of line current and angular velocity, Equation ( 8), it is possible to estimate its value. Attending to Equation (7), if the voltage provided by the battery, or the power supplier, is known, direct current necessary to operate in that point can be determined. Finally, the energy consumed by the battery if it remains performing the manoeuver for t seconds, can be estimated by multiplying direct current by the time.…”

“…It is true that the COVID19 pandemic has had a negative short-term impact in the capacity of companies to invest in this novel technology; however, it is expected that the companies promote the automatisation of their processes, and here, drones could have a relevant role. From the standpoint of commercial applications carried out by drones, the market is focused on light platforms, which are equipped with electric propulsion systems [3][4][5][6][7][8][9]. This market expansion is conditioned by the regulatory framework.…”

Predicting Stand Volume by Number of Trees Automatically Detected in UAV Images: An Alternative Method for Forest Inventory

“…An alternative for counting the number of trees would be the individual tree detection with the use of Unmanned Aerial Vehicle (UAV) systems or airborne sensors [19][20][21][22][23][24][25][26][27] where the detection rate can vary from 70% to 114%, depending on the type and characteristics of the sensor used, the algorithm method, the age, species, spacing and management conditions. This is a useful method for obtaining data, being a relatively inexpensive and automated process that can support several types of sensors [28,29] highlighted the potential of using data obtained by UAV systems in the forest inventory with many innovations based on the tree detection.…”