What may have seemed like science fiction a few decades ago is fast becoming accepted tree care technology that is safer, easier and even elegant in its application for today’s arborists. Whether it’s robotics, 3-D printing or the use of infrared cameras for thermal imaging, such cutting-edge technology is at the forefront of today’s tree care equipment and promises to increase safety, enhance production and fill in the gap where labor shortages are most difficult to fill. This article will explore these three technologies and their general uses, as well as their more specific applications for tree care.
Infrared thermography
With almost 50 years of experience in the field of thermography, Italian expert Dr. Giorgio Catena, along with his colleague, Lanfranco Palla, eventually honed in on tree-damage detection, resulting in a procedure registered under the name “Treethermography.” As Catena explains, the images obtained with an infrared camera during Treethermography allow for the early detection of various alterations in trees, including decay and/or cavities, and any resulting adaptive growth in response to damage or stress.
Additionally, he says of the technology, “Advantages include total noninvasiveness, rapidity of use, the provision of ‘real-time’ information and the possibility to store images. Comparing them with images taken at a later stage, it is possible to quantitatively determine the evolution of damage.”
Treethermography, also known as infrared thermography (IRT), works by using an infrared camera system to detect the thermal differences between healthy and damaged zones within a tree. “At first, we could not fully explain how the method worked,” says Catena, “but we soon realized it was related to the thermal conductivity of wood which, although low, is not zero. The system works because heat transmission decreases in the area of decay, to the point of reaching its minimum in the presence of cavity, therefore the area corresponding to the decay/cavity presents a lower surface temperature than the surrounding healthy areas. The greater the temperature drop, the greater the extent of damage.
“The pattern appears in a range of gray or color palettes that can be selected as desired,’” Catena continues, “producing a ‘thermal map’ in which the area overlying decayed wood or a cavity is usually cooler than the surrounding area. Thermal conductivity in wood is mainly linked to tissue humidity and density and decreases as the liquid content decreases; that is why the areas with a cavity (no tissue) or decay (less heat-conveying liquids) have a lower surface temperature than healthy areas. The more the decay, the lower the surface temperature in the area covering it.”
According to Catena, the system can measure the whole tree from the ground up, from its base to the highest branches. He adds that the shaded side of the tree must be filmed, “because the sun heats up the area it hits, altering the tree’s surface temperature and thus hiding any existing problem. In the case of a temperature difference that is not justified by foreign elements, such as wounds, scars, hollows, epiphytic plants, etcetera, there is decay. Experience also has shown that if there is a temperature drop at the collar level, there is decay in the root system; thermography is the only technologically advanced method that can detect this.
“The method is not a ‘point-and-assess’ method,” he adds. “Thermal images must be interpreted, which the operator does in the field, at the time of filming, without any specific software. To do this knowledgeably, it is important to know the theory of infrared radiation and be familiar with the thermal camera. Modern FPA (focal plane array) thermal cameras are portable and battery operated. They store images on magnetic media and provide thermal images in real time. These images are in JPEG format, and can immediately be used in any Word or image-processing software.”
According to Catena, measurements are quick, with images of an entire tree taken, interpreted and stored in five minutes. “In eight hours of intense work, even a hundred trees in an urban setting can be measured. An additional advantage is that the method can operate at a distance of 20 to 25 meters (22 to 27 yards), and therefore allows the detection of cavities that would otherwise only be accessible by climbing or via hydraulic platforms. This clearly saves users inconvenience, time and personal risk.”
According to research on IRT, its main limitation is that it does not identify whether the detected damage is a void or deteriorated tissue. The thermal image accompanying this article clearly shows that the technique reveals the extent of the damage within the trunk and branches, both in width and height. The extent of decay, i.e., the volume of damaged tissue or cavity, can be deduced from the drop in surface temperature it produces and by the color shown on the tree surface; the color depends on the color palette chosen. An arborist with a minimum of thermal-imaging experience can quantify the damage from mild to severe. Finally, trees that have large areas hit by direct sunlight or that are wet should not be measured; arborists should schedule infrared thermography accordingly.
Possibly due to the cost of infrared camera equipment, thermal tree imaging remains a less utilized technology than that of the invasive increment borer or the Resistograph. But with a trend in the industry toward saving mature trees, this cutting-edge technology clearly has enough advantages to make it a tree care technique worth investigating and pursuing.
Above, the same tree’s thermography shows, in green, the presence of a cavity/deteriorated tissue going from the base of the tree to the remaining branch; the vital tissue is rendered in yellow and brown. The photo on the right shows the situation detected. All three images courtesy of Dr. Giorgio Catena.
Robotics technology
Anyone who saw the sci-fi movie “Avatar” no doubt remembers those military exoskeletons that allowed their operators to “feel” what the robotic suit was doing. Enter the groundbreaking innovations of Sarcos Technology and Robotics Corporation, based in Salt Lake City, Utah. According to its website, the company is “revolutionizing the future of work across the private and public sectors through its advanced line of robotic products that augment, rather than replace, humans.
“By combining the intelligence, instinct and judgment of humans with the strength, endurance and precision of machines, the result is a workforce that is not only safer but significantly more productive.”
Sarcos Technology’s original product was the trademark-registered Guardian XO, a full-body, battery-powered exoskeleton with a futuristic look. It’s been used successfully in applications that include manufacturing, construction and field service, allowing a single person to deliver the productivity of many workers.
Their next product, which currently is in the testing phase, is the Guardian XT, a teleoperated dexterous robot. This remotely operated robotic arm has been especially intriguing to those in the tree care industry, though its uses are far reaching. According to Kristi Martindale, Sarcos’ chief product and marketing officer, the robots are being tested “for a variety of industrial uses in order to keep workers safe from injury while increasing productivity and addressing critical labor shortages that are present across almost every skilled labor industry.
“Our robots have the potential to reduce the likelihood of occupational injuries, equalize the workforce by enabling more diversity, extend the longevity of workers’ careers and alleviate the pressures of labor shortages by keeping skilled workers safe and out of harm’s way,” she continues. “When we set out to develop the Guardian XT, we wanted to provide a mobile robot that would allow an operator to perform tasks requiring human-like dexterity, while keeping the operator at a safe distance in challenging or hazardous environments, such as at-height work. We used the arms of our Guardian XO as the basis of this robot. The arms can be mounted to a variety of mobile bases and lift platforms and can be operated remotely.”
While the Guardian XT shows significant promise in areas such as utility- and power-line maintenance, aviation maintenance and infrastructure repair, it is in the area of challenging tree work that the technology could shine. “Sarcos has performed testing in vegetation management with very positive feedback from our prospective customers,” says Martindale.
In watching a video released by Sarcos, TCIA staff were impressed that the operator of the Guardian XT had his back to the tree-pruning process the entire time, watching the operation solely through his headset. This led to the question of whether the operator could conceivably conduct tree trimming from inside their truck if it was raining.
“If the correct connectivity method is used to enable communication between the operator and the robot, and the operator has enough space to move their arms to operate the robot, operations such as tree pruning could be accomplished from inside a vehicle or elsewhere,” Martindale remarks. “For example, on a hot summer day when the operator needs to escape being in heat and direct sunlight, the robot also could be operated from a more remote distance, such as from a nearby building or a remote-control center, to eliminate the need to be directly in the environment where the robot is working.”
Speaking of connectivity, Martindale notes that the range limit between the operator and the robot is largely dependent on the type of connectivity method used – for example, Wi-Fi, 4G/5G or tethered options.
“Selecting the right connectivity method also will depend on the customer’s teleoperation requirements,” she says. “We believe that in most scenarios, the operator will control the robot from the ground, away from active power lines but still near the vehicle. This type of teleoperation scenario can be supported by either tethered or wireless connectivity. However, if a customer wants to control the entire workflow from a centralized, remote location, a connectivity method like 4G/5G or Wi-Fi will be the preferred connectivity option, given the limitations of tethered connectivity.”
Each arm of the Guardian XT can lift and manipulate up to 100 pounds of payload, and the robot itself can be affixed to various commercial lift machines via a generic mounting structure. “The robot weighs approximately 250 pounds and can be mounted to virtually any lift that is graded to support this weight,” Martindale explains. “Additionally, there are sensors on the operator’s arms that are a component of our proprietary SenSuit wearable controller system. The SenSuit enables dexterous control of the robotic arms, end effectors and trade tools. It also provides situational awareness of the robot’s interactions with its environment through a force-feedback system. Finally, haptic (tactile) feedback enables the operator to gauge the force used when gripping objects like trade tools.”
According to Martindale, Sarcos expects to begin initial production of the first commercial units of the Guardian XT robot at the end of 2022. To kick off the release of this new technology, Martindale says Sarcos is offering customers a “Robot-as-a-Service” model in which a customer pays for use of the robot for a certain period of time in what is essentially a full-service lease package. “This includes training, maintenance and upgrades of the robot,” she notes, “though really, there is minimal training required to operate the Guardian XT robot.”
To view a video of the Guardian XT in action, visit Sarcos Technology and Robotics Corporation’s YouTube channel, Video: Guardian XT: Tree Trimming Demo (https://www.youtube.com/watch?v=HxuhrZHQWFs).
3-D design and printing
With a background in design engineering, Russ Davis – CEO of Arborjet, Inc., and founder/owner of Celero Partners – is pioneering the use of 3D design, scanning and printing in the production of equipment for plant health care, as well as for other disparate industries that include medicine, manufacturing, commercial diving and even the cannabis industry. Celero is conveniently located at Arborjet headquarters in Woburn, Massachusetts, meaning that staff assemblers can produce product prototypes for testing on the spot, followed by immediate tweaking of the prototype design as needed.
Davis launched Celero Partners five years ago with one 3D printer; he now has 12 printers that handle a variety of materials and design functions, and he says his company has completed hundreds of projects for various clients in those five years. The beauty of 3D printing, he says, “is using a computer design system to create a 3D model, and then having the ability to print out several prototypes right away. This allows you to immediately make changes to something you design and create.
“Instead of drawing a full design and then sending that off to a machine shop, which could take two to three weeks, now we can design and print something in-house and have three prototypes within a couple of days,” notes Davis. “That represents a huge time and cost savings. Not only that, it accelerates the design phase and allows us to optimize the design really fast.”
According to Davis, there are two basic types of 3D printing. The first he likens to plastic fishing line that lays down into the design and then is melted into shape. “That’s by far the most popular and what we produce the most,” he notes. The second method utilizes a liquid bath of whatever material the equipment will be made of, and then a laser solidifies the design within the bath.
Whether using polymer/plastics or carbon fibers, Davis says the applications for 3D printing are endless. “I actually created a plastic mask in the early COVID-19 days, when masks were hard to come by,” he says. “Unfortunately it wasn’t comfortable to wear, and so it never took off.” Other projects Celero Partners has tackled, successfully, include producing small, foam-filled buoys that are part of a safety device used by commercial divers, as well as a strainer-and-funnel system in six different sizes that is used in the cannabis industry.
In the tree care industry, the shining star of Davis’ 3D-design and -printing projects no doubt is Arborjet’s patented AccuFlo Soil Injector ISD, “the most-used injection tool in tree care today,” he says. “For the grip, I scanned my hand and then a couple of other hands, both men and women at Arborjet, in order to come up with the ideal, most comfortably ergonomic shape.
“(In the 3D printing process), we used carbon fibers for various brackets and moving parts within the tool. This makes it lighter in weight and more ergonomic than if we were using any other material, like metal,” he explains. “Metal and even aluminum can rust and deteriorate. Carbon fibers are more durable, they don’t rust and they’re three to four times less expensive.”
Coming full circle, Davis says they actually utilized 3D design and printing to create specialized equipment for assembling various 3D-designed and -printed products at the Arborjet facility in Woburn. “A lot of these products are assembled right there on the Arborjet floor,” he notes, “so we utilized the technology to quicken assembly and make things more ergonomic for the assemblers.”
Eye on the future
All in all, it’s proving to be an exciting time to witness cutting-edge technology within the tree care industry. Expect to see more of such unique innovations as the industry continues to seek answers for increasing safety, enhancing productivity and easing labor shortages.
