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Press Resources: Witness Tree Social Media

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Press Release: High-Tech Tree Tells Climate Stories Online

As trees across the U.S. continue their picturesque march toward autumn, one 100-year-old oak tree in Massachusetts is attracting a crowd of admirers online. The tree is a scientific wonder—not because of its unique looks or a special way it grows, but because of its voice.

The idea for the Harvard Forest Witness Tree, a social media outreach project led by post-doctoral fellow Tim Rademacher of Northern Arizona University and Harvard University, began as a public outreach component of a study investigating the effect of environmental changes on wood growth, funded by the National Science Foundation... (read more)

Press Contacts

Kate Petersen, NAU Ecoss Coordinator: 928-523-2982;

Clarisse Hart, Harvard Forest Outreach Director: 978-756-6157;


(click to download high-res)

dendrometer sensor embedded in Witness Tree trunkA sensor called a dendrometer, installed on both the trunk and a branch of the Harvard Forest Witness Tree, measures changes in the tree’s diameter multiple times per minute. The data collected by the sensor is analyzed and posted to social media to show how the tree is growing. Photo by Shawna Greyeyes.







The Witness Tree's foliage in October 2019.  Photo by Clarisse Hart. (See a real-time selfie from the tree here.)









two scientists measure trunk respiration in an oak treeThe 2018 Witness Tree research team checking carbon dioxide respiration on a nearby tree (L-R - Tim Rademacher and Kyle Wyche). Photo by Sara Plisinski.






three scientists standing in front of the Witness Tree


The 2019 Witness Tree research team in front of the tree (L-R – Tim Rademacher, Shawna Greyeyes, Clarisse Hart). Photo by Roberto Carrera-Martinez, Harvard Forest.






Witness Tree in autumn, showing the tree's surrounding cameras and sensorsThe Witness Tree in autumn. Cameras and other instrumentation are visible around the base of the tree and on its trunk. Photo by Clarisse Hart.