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Tree Listening


Have you ever wondered what happens behind the bark of a tree?

The Tree Listening Project uses highly sensitive microphones to make audible the 'rumble' of tree movement and the 'popping' of ascending water mixing with cavitated air in the xylem - the very life of the tree surging up from the roots towards the leaves.


The project aims to provide an experience that engages and inspires a keen interest in trees.


Judi Dench and myself Tree Listening on set of the filming of Judi Dench - My Passion For Trees.


The Tree Listening Project has two forms:

The Tree Listening Device

The Tree Listening Device is a microphone, developed in 2007, to capture the 'hidden sounds' behind the bark. It allows the listener to hear the water, mixing with air, as it travels up through the xylem tubes. This happens as the leaves lose water through the transpiration process. The device is not yet in production and thus not available for sale. It is used, by Alex, in conjunction with the Tree Listening Installation.

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The Tree Listening Installation

The Tree Listening Installation was developed in conjunction with The Tree Listening Device in order to allow multiple listeners to hear the live sound of a tree simultaneously. The sound is presented through the intimacy of headphones to accommodate a truly personal experience. 

The Tree Listening Installation is a travelling, educational tool used to facilitate a deeper understanding of ‘how trees work’.


Workshops can be provided for school groups and give a stimulating environment in which to further explore the transpiration process through the ‘hidden sounds’ behind the bark. These activity-based workshops can consist of either;

-a short 30 minute overview or

-a morning/afternoon session exploring the transpiration process in greater detail.

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Having the Tree Listening Installation at your location.

The Tree Listening Installation travels in three different formats:


A temporary installation:

Installed on a daily basis and accompanied by Alex Metcalf

£260 per day

+ 45p/mile travel

+ £100/day of travel time

+ Accommodation.

I will be with the installation on a daily basis to talk to the public and explain all about the hidden movements inside the tree.


A monthly installation:

Where the installation is self contained and solar powered playing a recording of the tree.

£1600 per month

+ 45p/mile travel

+ £100/day of travel time

+ Accommodation.


A permanent installation:

With a recorded sound from the tree.  £45,000 approx

With a live sound from the tree. £75,000 approx