The Harvard Forest Witness Tree (@awitnesstree) claims to be the oldest known living organism on social media. In 2018, Tim Rademacher installed sensors on and around a 110-year-old Northern Red Oak (Quercus rubra) in Harvard Forest, Petersham, Massachusetts, after being inspired by Lynda Mapes' book Witness Tree and scientists at TreeWatch.net. Rademacher used the Harvard Forest data archive to contextualise the sensor data with over 55 years of climate data. Technologies include: a dendrometer for measuring real-time tree growth; a sap flow sensor; a phenocam used to detect seasonal changes in leaf fall and colour over time; LiDAR to make 3-D images; and long-term weather data such as soil temperature, relative humidity, and wind speed. A computer programme then translates data from the tree into Twitter and Facebook updates.
On the Internet of Nature podcast with Nadina Galle, Rademacher discussed the scope for expanding A Witness Tree to other trees, not only to collect more environmental data, but also to explore the effectiveness of different environmental communication strategies. In 2022, there will be three additional witness trees in Cambridge, Lincoln, and Boston, Massachusetts. For more information, see the Witness Tree webpage here.