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Site-Specific Shade Assessment, USGA Central Region Update

Posted on December 8th, 2020
By: John Daniels, agronomist, Central Region

The Solar Pathfinder can help you identify obstacles to sunlight and determine the amount of light that an area potentially receives for each month of the year.  

Tree removal is arguably one of the most difficult tasks to carry out on a golf course. That’s not to say the act of cutting down and cleaning up a tree is overly complicated and beyond the abilities of the course maintenance team. In fact, most maintenance departments have the necessary tools and skills to complete significant amounts of tree work in-house. Trying to convince key decision-makers which trees need to come down and why is usually the greatest challenge.

When it comes to tree removal priorities, addressing shade is frequently at the top of the list for superintendents. Many tech-savvy superintendents have found success using mobile apps like Sun Seeker or Sun Surveyor to help make the case for tree removal. These apps allow the user to quickly visualize areas where the sun is blocked on a given date and estimate the amount of sunlight hours it receives. USGA agronomists also routinely use these apps during Course Consulting Service visits to identify problematic trees and help build consensus among golfers about the need to take down a particular tree.

Although these apps are certainly convenient and useful, they are unable to demonstrate the total amount of sunlight available over the course of the entire year, and instead only provide a snapshot on a single day that is selected by the user. This limitation is what led Tim Burch, superintendent at St. Louis Country Club in Missouri, to the Solar Pathfinder. With this tool, he is able to quickly quantify the maximum amount of available sunlight for not only a single day, but for each month of the growing season. He can also identify other obstacles that interfere with sunlight at various times of the year. This has allowed him to better understand tree shade implications for key turf areas and show where improvements can be made.  

The Solar Pathfinder has been around since the 1970s and was originally created to help position solar panels so that the greatest amount of energy is captured. Its design also allows for many other uses, such as helping to determine why turf is struggling because of shade. The tool works by casting a 360-degree reflection of the surroundings over lines that indicate the sun path, time of day and month of the year. You can see which surrounding features will obstruct the sun at various times of day during any given month of the year and you can also easily calculate the amount of potential sunlight for a given month. For example, during October your chronically weak green might only receive 25% of the total sunlight. This information could help explain which trees are limiting turf health and be used to guide tree removal efforts. The tool is relatively easy to set up and can be used during any time of the day or year, and in cloudy or clear weather, the sun’s position at the time of use is not an issue.

Removing trees to improve turf health can certainly be a sensitive subject, but hopefully tools like the Solar Pathfinder can help superintendents overcome the initial reluctance that many individuals have when tree removal is discussed.

Central Region Agronomists:

John Daniels, agronomist – jdaniels@usga.org

Zach Nicoludis, agronomist – znicoludis@usga.org

Information on the USGA’s Course Consulting Service

Contact the Green Section Staff

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