A New Way to Look at Trees

Red represents the hottest areas on the surface of the tree and blue represents the coolest areas. Images - Trees Project Limited

A new field of research in arboriculture has surfaced that interprets infrared images to determine the health of the wood inside trees. This summer, some of Almstead’s Arborists had the opportunity to meet with project leader Dr. Marcus Bellett-Travers to learn about this new technology. The interpretive software was developed in the UK and is now available in the United States. Almstead is looking closely at this technology and may be incorporating it into our company in the future.

How Does it Work?

Infrared imaging is a completely noninvasive process that allow us to examine the wood inside of a tree from root to crown in a relatively short amount of time. To create an image, infrared cameras read surface heat levels and place them on a color spectrum. On the examples in this article, red is used to represent the hottest areas on the surface of each tree while blue represents the coolest areas.

The surface heat of trees radiates from the inside, where water and nutrients are moving through the wood. Sections of the tree where wood fibers are intact (called functional wood) conduct heat much faster than areas where those fibers are damaged. So the color spectrum on an infrared image of a tree is a graphic representation of the spectrum of functional wood within that tree.

What is it Used For?

The amount of functional wood in the trunk of this Beech dissipates from bottom to top, left to right, which is evident in the dieback of the crown - Especially on the top right side of the tree.

The advantages of a system like this are tremendous. As Arborists, we spend a lot of time weighing the potential risks alongside the benefits of individual trees. While large, older trees are often the most valuable assets on a landscape, they require careful management and can become quite hazardous. With the detailed information infrared imaging provides, the decisions we make regarding tree preservation and hazard assessment can be better informed.

Infrared images of trees help us in a number of ways. For instance, we can use them to locate serious areas of internal decay that wouldn’t otherwise be visible. On an older tree, we can see which limbs have the most functional wood before making pruning decisions that may extend the lifespan of that tree. We also know that the more functional wood a tree has overall, the better it withstands stresses to its environment – so infrared imaging can help us determine which trees may or may not withstand the stresses associated with construction projects.

It’s important to note that no tree is composed entirely of functional wood. In fact, as a tree ages, plenty of its wood degrades and ends up playing a more structural role. The most dangerous losses in functional wood are the result of spreading decay due to pathogens, insects or injury. Regardless of the cause, the ability to track the location, severity, and spread of degraded wood is an incredible advantage for any arborist.