Sap Rising — Listening to an Ancient Oak Forest
Early April. The first real warmth of spring has begun to move through the land, and with it the slow awakening of the great oak. This recording forms part of my ongoing project exploring new ways of listening to trees in order to better understand how ecosystems are responding to climate change.
Working with an ancient oak, I installed specially adapted contact microphones fitted with fine probes, carefully inserted into the tree’s cambium layer, the living tissue where growth and nutrient transport occur. These sensors were connected to specially designed ultra-low-noise, high-gain preamps capable of revealing signals far below the threshold of ordinary hearing. The aim was to listen to the hidden interior of the tree: a sonic world that normally remains completely inaccessible to human perception.
As the morning warmed, the microphones began to reveal faint pulses and subtle internal movements. What we are hearing is the rising of sap; water and nutrients being drawn upward through the vascular system of the tree as spring growth begins. These minute vibrations manifest as delicate crackles, murmurs and rhythmic flows within the wood itself. Occasionally the structure of the oak responds with gentle creaks and micro-vibrations as temperature shifts expand the fibres and the trunk adjusts to the day’s warming air.
These sounds offer a rare glimpse into the physiological processes of the tree. The movement of sap reflects hydration levels and metabolic activity, while structural sounds can indicate how the tree responds to environmental stresses such as drought, heat, or sudden temperature change. In this sense, the oak becomes both instrument and archive, its internal acoustics recording the environmental conditions it lives through.
This recording forms part of a broader effort to map the soundscape of a tree and its ecological relationships.
By combining internal recordings with the surrounding habitat, insects, wind in the canopy, and the subtle exchanges between organisms living on and around the tree,the project seeks to create a holistic sonic portrait of a living system.
Listening in this way reveals the tree not as a silent object, but as a dynamic participant in a complex network of life. Through this sonic exploration, the project aims to draw attention to the fragile interconnections of ecosystems increasingly affected by climate change, and to encourage a deeper form of listening to the living world.