Electricity from trees

Researchers from Queensland University of Technology (QUT), in Brisbane, Australia have published findings from a study showing ion concentrations in heavily wooded areas to be twice that of grassy areas. The increased ion counts are believed to be caused by the trees transporting watersoluble radon from ground water into the atmosphere as they transpire. The research paper is available from Environmental Science & Technology.

The role of ions in the production of atmospheric particles has gained wide interest due to their profound impact on climate. Away from anthropogenic sources, molecules are ionized by alpha radiation from radon exhaled from the ground and cosmic gamma radiation from space. These molecular ions quickly form into ‘cluster ions’, typically smaller than about 1.5 nm. Using our measurements and the published literature, we present evidence to show that cluster ion concentrations in forest areas are consistently higher than outside. Since alpha radiation cannot penetrate more than a few centimetres of soil, radon present deep in the ground cannot directly contribute to the measured cluster ion concentrations. We propose an additional mechanism whereby radon, which is water soluble, is brought up by trees and plants through the uptake of groundwater and released into the atmosphere by transpiration. We estimate that, in a forest comprising eucalyptus trees spaced 4m apart, approximately 28% of the radon in the air may be released by transpiration. Considering that 24% of the earth’s land area is still covered in forests; these findings have potentially important implications for atmospheric aerosol formation and climate.

( Via PhysOrg )

Brains from the BBC

3 BBC News items on brains

Is this what thoughts sound like?

University of California psychology and neuroscience professor Bob Knight explains how computers are being used to decode imagined speech.

World premiere of brain orchestra

Brain waves from thoughts of sounds used to move cursor

Moving a computer cursor by thinking about a series of vowels.

Archaeoacoustics around the world

The Landscape & Perception project of Jon Wozencroft & Paul Devereux is conducting ongoing research in "Archaeoacoustics."

Previously mentioned here by Gordon, ancient sites with acoustic "ringing rocks" have been discovered all over the globe. Of note is research conducted by the L&P team with ICRL fellows ( lead by Robert Jahn, formerly of PEAR ) whose paper "Ancient Architectural Acoustic Resonance Patterns and Regional Brain Activity" appeared in Time and Mind, March 2008.

Percussionist Z'ev has played on lithophones in Carn Menyn, Wales ( see the bottom of the sidebar here for photos and a sampling of the sound ).

The Sound Machine

Roald Dahl's "The Sound Machine", first published in the September 17, 1949 issue of The New Yorker, proposes a device that can pick up high frequency sounds and convert them into the range audible by humans. The inventor of the machine first hears shrieks of roses being cut by a neighbor. Taking an axe to a beech tree the next day, he is surprised to hear "a harsh, noteless, enormous noise, a growling, low-pitched, screaming sound..."

A radio dramatization of the story is on in MP3 format.

Several short films have been inspired by the short story. Two on YouTube are embedded below.

Scans of the original issue of The New Yorker are available via one-time payment or subscription at their site.


Researchers from Columbia University, the University of Maryland, and the Smithsonian Institution have joined forces to develop a series of electronic field guides. Their first effort, Leafsnap, uses visual recognition algorithms to identify trees via photos of their leaves. Their species list is currently limited to trees found in the New York City and Washington D.C. areas, but will soon grow to cover the continental United States. Leafsnap is available as a free iPhone app at the iTunes App Store. ( Via Kottke and Garden Design )