What if a machine could detect insects and diseases in living trees or help prevent log theft and illegal logging by tracking individual logs from the forest to the lumberyard? What about a machine that researchers could use to identify and understand the ecological roles of microorganisms, insects and other invertebrates that live in and on trees?
It may sound like the stuff of science fiction, but such machines do exist, and they’re called electronic noses, or e-noses. Dan Wilson, a U.S. Forest Service research plant pathologist with the Southern Research Station Center for Bottomland Hardwoods Research, recently published a 2013 review article on the uses of e-nose devices in agriculture and forestry in Sensors, a leading international journal on the science and technology of sensors and biosensors. Wilson recently received the 2013 Sensors Best Paper Award for his 2009 review article, “Applications and Advances in Electronic-Nose Technologies.”
E-noses mimic the mammal sense of smell, and while they are not as complex as the human olfactory system, they can provide real-time information about the chemical and physical nature and quality of plants, and plant and animal products. E-noses ‘smell’ with sensors, and recognize mixtures of gases rather than individual gases. Gas emissions at lumber mills and forest-product manufacturing facilities are often complex mixtures of gases, and e-noses are widely used to monitor, detect, and control hazardous waste emissions from these industries.
Plants make a wide range of chemical compounds, and many of these compounds boil at low temperatures, easily becoming airborne as gases. These compounds are called volatile organic compounds, and e-noses are especially useful for detecting them. Stressed plants, whether insect-infested or diseased, emit abnormal chemicals that e-noses can detect. This information can provide land managers and researchers important clues about what’s happening below the bark. Wilson pioneered the use of e-noses in diagnosing tree diseases and identifying damaging insects like termites and microbial pests that cause vascular wilt, wetwood, and wood decay. Detecting wood decay early is especially important in urban forests, as falling trees or branches could injure people and damage property.
From The USFS Southern Research Station: https://www.srs.fs.usda.gov/compass/2013/04/11/electronic-noses-and-forests/