Detecting Fir Mistletoe Using High-Resolution Aerial Photogrammetry

EAASI Company: Phase One

Project Overview

Fir mistletoe (Viscum album) infestation is a major threat to forest health in Poland, leading to the gradual decline and rapid decomposition of trees. This phenomenon impacts carbon storage, biodiversity, and the timber industry, making it a critical concern for forest management. Identifying and documenting mistletoe infestation over large forested areas has traditionally been slow and labour-intensive due to the difficulty of visually isolating mistletoe within tree foliage.

AlterGeo Holding, a company specialising in remote sensing from ultralight aircraft, addressed this challenge using high-resolution aerial photogrammetry. Their approach allowed for rapid, detailed mapping of forest health over large areas, significantly improving efficiency and accuracy in detecting tree diseases.

Image courtesy: Phase One

Technical Solution

AlterGeo Holding deployed a high-performance aerial imaging system to monitor and assess mistletoe infestation at scale. The solution involved:

• High-Resolution Aerial Data: Data acquisition was performed using the Phase One PAS 280 large-format photogrammetric camera mounted on the Alter-Eye aircraft. The system achieved a Ground Sample Distance (GSD) of 2 cm, allowing for precise identification of mistletoe infestations and tree health down to individual branches.
  

• Optimised Flight Performance: The Alter-Eye aircraft’s excellent flight characteristics and large payload capacity allowed flights at low altitudes and speeds, with a high longitudinal photo coverage of 60%. This configuration enabled rapid and consistent data capture over large forested areas at a rate of 4,000 hectares per hour.
  

• Advanced Data Processing: Captured images were processed to differentiate tree species and detect mistletoe infestations. High-resolution outputs enabled clear identification of tree health status, including early-stage infections and patterns of decline. The data provided actionable insights for forest managers to develop targeted response strategies.

Image courtesy: Phase One

Project Benefits

The high-resolution aerial photogrammetry system provided several key advantages for forest management:

• Increased Efficiency: Mapping at 4,000 hectares per hour is 50 to 100 times more efficient than drone-based methods with similar resolution.
  

• Accurate Tree Health Assessment: The detailed imaging enabled the identification of mistletoe-infected trees and assessment of infection severity, allowing for targeted intervention.
  

• Climate Impact Mitigation: Early detection and management of mistletoe infestation help reduce carbon release from tree decomposition, supporting climate protection goals.
  

• Strategic Forest Management: Insights gained from aerial data inform decisions on forest health maintenance, logging schedules, and replanting efforts, improving overall forest resilience.

Future Outlook

This successful application of high-resolution aerial photogrammetry demonstrates the growing potential of crewed aerial data in forest health monitoring and environmental management. This project highlights the value of advanced imaging systems in identifying environmental threats at scale and guiding strategic responses. The technique has the potential to become a standard tool in forest management, improving accuracy, efficiency, and environmental impact mitigation.

Phase One published a more detailed article about this case: Detecting forest tree diseases using a large-format camera on an ultralight aircraft

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Learn more about how other EAASI members utilise crewed aerial technology to address global challenges in our Use Cases series, a dedicated section showcasing real-world applications and achievements by EAASI’s diverse members.