Trinity scientists enlist ‘witness trees’ for climate tracking project

23 Sep 2024

Image: © alessandro0770/Stock.adobe.com

The Witness Tree project will run for 30 years, collecting samples and data that might shape future green policies.

Trinity College Dublin (TCD) scientists have chosen a selection of 21 new ‘witness trees’ from the National Botanic Gardens to track how the climate crisis is progressing in Ireland for the next three decades. 

The addition is part of the second phase of the Witness Tree project, as phase one of this project was based in Trinity’s Botanic Garden with the first set of 21 trees. 

Trees have a long life and are able to witness the various effects the climate has on them, providing detailed datasets for researchers. They are also highly responsive to their environment, moulding themselves and their physiological behaviour to adjust to the climate around them.  

The Witness Tree project will be collecting data every year for a total of 30 years, saving samples for studies and policymaking. The collected data is also publicly accessible. 

By conducting studies on the witness trees in the gardens and comparing them to existing green policies, scientists hope to assist governments in understanding which policies are effective. They will also monitor what species responds best to the changing environment. 

The TCD team of scientists consisting of Midori Yajima, a PhD candidate from Trinity; Michelle Murray, the outreach manager at Trinity Botanic Garden; and principal investigator Prof Jennifer McElwain, a professor of botany at Trinity’s School of Natural Sciences, will be collecting and saving these ‘snapshots’ for future studies.  

“Trees are incredibly reliable witnesses to the effects of climate change. They are, in effect, giant biological sensors with the potential to provide scientists with detailed, highly accurate, long-term datasets on the state on the environment,” said McElwain. 

The witness trees vary from different origins and climates, ranging from Australian blackwood, Indian chestnut and strawberry, to date palm and redwood. 

The scientists are collecting various kinds of data including the rate of exchange of water and carbon dioxide between the plant and the atmosphere – also called stomatal conductance – to be used as a general indicator for the tree’s health and to track how this changes with the environment. 

The team will also monitor particulate matter, or smog that can stick to leaves and barks, which will help tell the scientists which trees are better at filtering out pollution. 

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Suhasini Srinivasaragavan is a sci-tech reporter for Silicon Republic

editorial@siliconrepublic.com