The two most common forest vegetation management objectives are to (1) minimize resource competition, and (2) to develop methods for managing specific weed species. This paper reviews relevant models and decision support systems for assisting in achieving these objectives. The aim of reducing resource competition is to increase crop-tree growth and survival. Several modelling approaches have been applied to this problem and these generally estimate crop survival and growth benefits following some form of generalized weed control. Linkages with models of older tree crops are needed for comparing vegetation management strategies in the context of complete silvicultural regimes. More refined individual tree models use competition indices to estimate the quantity of weed vegetation within the growing space around each tree. The indices reflect resource use by the weeds and are sensitive to changes in weed growth over time and to the application of specific vegetation management treatments. Hybrid and process-based models have the potential to provide more generalized models of inter-specific competition, but their usefulness for forest practitioners has yet to be proven. Some forest vegetation management problems require a more detailed understanding of the biology and ecology of a specific species. In this case, different modelling approaches that consider overall weed population dynamics, distribution or spread may be appropriate.

Forest health can be adversely affected by invasive organisms. Biosecurity measures to prevent the establishment of harmful invasive organisms at national points of entry (e.g., airports or shipping ports) are vital to protect forest health. Innovations in pest eradication technologies are being developed based on their efficiencies and effectiveness. However, the question of whether people find them acceptable is rarely considered. In New Zealand, research is underway into the use of highly targeted pesticide spraying using unmanned aerial vehicles (UAVs) as a novel technology to eradicate pest species that impact forest, food, and fibre sectors. Public approval for such technologies, however, can be a critical aspect for their success. A tool can be technically effective (achieve eradication), but uptake may be impossible if communities do not trust the technology. We developed a method for enabling discussions about the use of UAVs and their acceptability in general before being operationalized for biosecurity. This paper presents an investigation of how “participatory-design”, an often tactile, visual, and inclusive process of community engagement can improve the acceptance of technology use in the public sphere. We asked people, both scientists and citizens, to evaluate the acceptability of a range of UAV uses (including biosecurity) along a continuum and then explored the reasons for their placement. Key criteria for acceptable and unacceptable uses were subsequently developed to help technology designers and operators consider aspects of social acceptability during design processes. Our tool and approach facilitated discussions around technology acceptability that were subsequently adopted by our technical design team for the development and the use of acceptable UAVs for biosecurity. This research shows how systematic approaches to design can help uncover and mitigate social acceptability issues through inclusive design under increasing threats of biosecurity, whether related to challenges of trade or climate change.

BACKGROUND: Multicopters are used for releasing particulates seeds, fertilizer and spray. Their low cost and high manoeuvrability make them attractive for spraying in steep terrain and areas where overspray is undesirable. This article describes a model of multicopter wake and its influence on particulate dispersion, which is computationally economical compared to many computational fluid dynamics (CFD) approaches, yet retains reasonable accuracy. RESULTS: A model was successfully implemented in OpenFOAM . It features source terms for the rotor wash, Lagrangian particle tracking, an evaporation model, and a porous medium approach to model the effect of the ground vegetation. Predictions were validated against the field tests of Richardson et al. which used a DJI Agras MG‐1 multicopter in three different flights with airspeeds of 3.2–4.9 m s ⁻¹ , ground speeds of 2.1–2.9 m s ⁻¹ and cross‐wind speeds of 0.04–2.2 m s ⁻¹ . The effective swath width (30% line separation) was predicted to within one standard deviation. Sensitivity to a rotor rotational speed, flight height, flight velocity, multicopter roll and yaw angles, surface roughness length, plant height and leaf density was checked. CONCLUSION: In all flight trials, the modelled swath was closest to the experimentally obtained swath when the surface roughness of the fetch was equal to 0.5 m (bushes) and the rotational speed of all rotors was equal to 2475 rpm with 0.75R (0.2 m) tall plant canopy (grass) introduced to the model. The model showed acceptable validity for flight velocities of ≤2.8–5 m s ⁻¹ when flight parameters can be approximately estimated. © 2022 The Authors. Pest Management Science published by John Wiley & Sons Ltd on behalf of Society of Chemical Industry.

Pest eradication strategies that use pesticides require application methods that have the lowest environmental and human health impact while maintaining the highest probability of success. This is highly important when eradication takes place in sensitive areas, such as urban or riparian zones. A new aerial application method, the spot-gun, was developed to provide good pesticide coverage on host species while minimising off-target exposure. This type of targeted aerial approach is useful in areas where conventional broadcast aerial spraying was historically used but was not ideal due to the quantity of pesticide hitting non-host species and going off-target. An even distribution of the active component is essential for eradication. The spot-gun method was tested and found to provide an even distribution of dye on the adaxial and abaxial leaf surfaces as well as in the top and middle regions in both the inner and outer portions of the canopy. The form of the deposits on the leaf surface was very different from that obtained using a broadcast aerial application with a conventional spray boom. The distribution results imply that the spot-gun method treatment will provide good efficacy. The implications of the different deposit pattern on efficacy are not known at this stage. This aerial spot-spray method has considerable potential as a tool for targeted aerial application of pesticides to small areas of difficult to reach canopies.