The National Academies

ACRP 04-27 [Active]

Alternative Methods to Manage Tree Growth Near Airports

  Project Data
Funds: $300,000
Staff Responsibility: Theresia H. Schatz
Research Agency: Mead & Hunt
Principal Investigator: Stephanie Ward
Effective Date: 5/10/2021
Completion Date: 11/9/2022

Trees around airports may penetrate the airspace surfaces established to maintain safe aircraft operations. The traditional method for monitoring tree growth is through surveys, which are often expensive.  If a survey has not been conducted in recent years, potential obstructions from tree growth could go unidentified, and could potentially contribute to an accident and possible liability exposure that can lead to a reactive approach. The issue is often more pressing at small airports with resource limitations that impact the monitoring and control. Alternative practices and new technologies, such as the use of unmanned aerial systems (UAS), light detection and ranging (LiDAR) or photogrammetry may provide more cost-effective solutions for gathering data.  Once data is collected, there are strategies an airport can utilize that have varying costs and benefits. Other ACRP reports have studied airspace and obstruction issues, however, there is no in-depth discussion of tree management and analysis related to obstruction issues.
Understanding all methods that are available allows airports to effectively balance the safety of operations and community interests. Research is needed to identify new technologies and practices to determine their effectiveness for monitoring and managing tree growth.
The objectives of this research is to create a guidebook that (a) identifies and evaluates alternative methods for obstruction related data collection and analysis, and (b) includes  strategies that effectively monitor and manage tree growth in and around airports. The guidebook should be applicable to different types, locations, and sizes of airports. The methods and strategies identified should be evaluated based on effectiveness, accuracy, ease of use, cost, training/expertise requirements and other relevant factors. 
The guidebook should consider, at a minimum:  
  • Methods of reporting data, validation of data collected, and action taken with appropriate stakeholders; 
  • A benefit cost analysis for alternate methods of mitigation (e.g., installation of light fixtures above the trees);
  • Different types of new technologies used for identification of existing or anticipated tree encroachments into the protected surfaces, (e.g., UAS, LiDAR, geographic information systems (GIS) software);
  • Different strategies to categorize the data and implement mitigation plans or actions;
  • Challenges with community issues;
  • A brief overview of protected airspace; and
  • Identification of case studies evaluating alternative methods of surveys compared to traditional methods.

The ACRP is seeking the insights of proposers on how best to achieve the research objectives. Proposers are asked to develop and include a detailed research plan for accomplishing the project objectives. Proposers are expected to describe research plans that can realistically be accomplished within the constraints of available funds and contract time. Proposals must present the proposers' current thinking in sufficient detail to demonstrate their understanding of the issues and the soundness of their approach to meeting the research objectives. The work proposed must be divided into tasks and proposers must describe the work proposed in each task in detail.

The research plan should include appropriate deliverables, for ACRP approval, that include at minimum:
1. Identification of alternative methods of data collection and analysis.
2. A summary of airport considerations and resources related to regional tree species, natural resources, and environmental data for plantings and eliminations.
3. Identification of factors related to the frequency of surveys, (e.g., tree species, growth rates, climactic conditions, airspace).      
4. A benefit cost analysis of interim evaluation methods compared to formal FAA aeronautical surveys.  
5. An interim report that describes work done in early tasks, including a description of their methodology used in their planned deliverable, an annotated outline, preliminary findings of the guidebook, and an updated work plan for remaining tasks. All of this should demonstrate to the panel the thought process behind how the final deliverables will address the components outlined in the objectives.
The research plan should include other appropriate checkpoints with the ACRP panel, including at a minimum (1) a kick-off teleconference meeting to be held within 1 month of the Notice to Proceed and (2) one face-to-face interim deliverable review meeting, as well as web-enabled teleconferences tied to the panel review and ACRP approval of other interim deliverables deemed appropriate.
The final deliverables will include:
1. A guidebook that meets the objectives and includes the previous deliverables as noted in the research plan; and  
2. (a) a Summary of Key Findings; (b) a Further Recommended Research Memo; and (c) a technical memo titled, “Implementation of Research Findings and Products”.

Status: Mead & Hunt has been contracted; research is underway. 

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