Climate-related sounds
– Clear string sound passing through the zenith: sun
Luminous intensity: volume; interruptions: clouds
no string sound or quiet string sound: overcast
– Muffled medium-frequency bubbling sound slowly changing frequency: humidity
Increasing humidity: higher frequency; decreasing humidity: lower frequency
– Deep gurgling on the ground, very slowly changing frequency: soil moisture
Increasing soil moisture: higher frequency; decreasing soil moisture: lower frequency
– The sound of rain, partly very short (due to speeding up), from above
Heavy rain: loud; light rain: quiet
– Wind frequently changing direction
Strong wind: loud; light wind: quiet.
Tree sounds
– High-frequency crackling (like that of a small fire) varying greatly in volume: sap flow in the trunk
Strong sap flow: loud; weak sap flow: quiet
– Clicking and popping, mostly after strong sap flow: cavitation sounds in the plant’s vessels, embolism of individual vessels
– Frequency of all tree sounds changing slowly: changes in trunk radius
Trunk shrinkage: higher frequency; trunk expansion: lower frequency
– Change in overall volume of tree sounds: amount of solar energy reaching the tree
Loud: large amount of solar energy; sunny day; quiet: small amount of solar energy; overcast