The Language of Trees II

A few months ago I wrote about the communication of plants and trees using hormones, which was often when a member species was under threat. However, this is not the complete picture as more research starts to come through of the influence of sound on plants as well as sound being produced by the plants themselves, and the production and measurement of electrical signals.

Lyall Watson (1939 – 2008) earned degrees in botany, zoology, geology, chemistry, marine biology, ecology, anthropology and a doctorate in ethology

This is not a new concept – South African born zoologist Lyall Watson  in 1973 wrote about the electromagnetic signals of plants connected to a lie-detector which could measure their ‘emotions’ which was dismissed by the scientific community. There is also the Federation of Damanhur, a communal ecovillage in Northern Italy, which have been conducting experiments on plants since 1975. The researchers there have used a variation of a simple electric circuit, known as a Wheatstone bridge to measure unknown electrical resistance. They found that the greatest signal variation occurred in the plants upon the arrival of the person who tended the specific plant most regularly.

Is there more going on when we water plants? (Getty Images)

Regarding sound, a recent paper1 shows  how young roots grow towards sound at 220 Hz which suggests they exhibit a frequency selective sensitivity. Moreover, they recorded the production of sound by plants, measured using a laser Doppler vibrometer, had definite spike-like structures which could not be explained by tension release in their water transport system. The researchers posit that sound could be particular useful for short range communication as well as being much cheaper biologically for plants to produce than hormonal chemicals. They also noted that the reception of sound underpins the behavioural organisation of all living organisms and the relationship with their environment – thus it should not be necessarily deemed as irregular in the life of plants.

Roots of young plants grew towards the specific sound source of 220 Hz (1)

What this suggests is that there is much still to learn regarding plants and trees, and these investigations may require interdisciplinary approaches. It also raises questions about the effect of the frequency of human vocal chords on plants, and if specific frequencies of sound can be used to help plants grow, as well as to encourage growth in particular areas of landscape.

  1.  Towards understanding plant bioacoustics. Gagliano et al. Trends in Plant Science, Vol. 17, Issue 6. pg 323-325, 22 March 2012

Inhibiting the Mafia and the Prevention of Illegal Logging

The value of rare wood attracts petty thieves, government officials and the Mafia. In fact, a new report from the United Nations finds that up to 90 % of tropical deforestation can be attributed to organised crime which controls 30 % of the global timber trade. Unfortunately illegal logging rates have actually been rising, with many ploys being initiated such as fake permits, bribed officials, hacked databases and mixing illegal timber amongst common stock.

The theft of tropical wood. Photo source: see ref (1)

Last month, Hang Serei Oudom, a Cambodian journalist who exposed illegal logging and corrupt officials involved in forest crimes was found murdered in the boot of his car. In April this year, tireless campaigner Chhut Vuthy, was shot dead by a Cambodian military policeman after refusing to hand over photographs showing illegal logging in the southwestern Koh Kong province. Or that’s the official version – his family insist a third person was involved. According to the UN, Cambodia’s forest cover has decreased from 73 per cent in 1990 to 57 per cent in 2010.

Chhut Vuthy, killed in April. (The Economist)

This destruction of natural habitat is with a double-edged sword, not only are threatened forests and their creatures destroyed, but deforestation followed by burning, largely of tropical rainforests, is responsible for an estimated 17 per cent of all man-made emissions (50 per cent more than that from ships, aviation and land transport combined)1. As the UN report notes, today only one-tenth of primary forest cover remains on the globe.

Project LEAF, an Interpol and UN collaboration

Unlike with drugs or ivory, shipping timber is still legal. However, Interpol recently stepped into the logging foray this year in June with the creation of LEAF (Law Enforcement Assistance for Forests). This is a combined effort by the UN and Interpol funded by the Norwegian government. The project’s objectives are:

  • Providing an overview and review of extent, primary geographic locations, routes, causes and structure of networks involved in illegal logging, corruption, fraud, laundering and smuggling of wood products;
  • Supporting countries in improved enforcement efforts;
  • Providing training and operational support;
  • Providing insights into the way organized criminals organize their activities;
  • Developing best practices for combating REDD-related and forest-related corruption.

While it is certainly positive that this initiative has been launched, enforcement is difficult when dealing with governments who are involved in the profits, and illegal logging is often taking place in countries with lesser degrees of law and order. This suggests to me that a combined use of tracking technology and enforcement would aid this project.

RFID tag, commonly attached to goods we buy. (BBC)

Radio chip tracking technologies are already on the increase by global brands to monitor products and customer behaviour, and some environmental use has started. The Instituto Ação Verde (The Green Action Institute) is using thumb-sized RFID devices to track over 2,500 Amazon trees. The Fraunhofer Institute is even working on a RFID tag comprised mostly of wood, to prevent adding impurities and extra labour in downstream processing, thus overcoming some objections from timber companies.

Perhaps LEAF is looking at this line of thought already, but it seems to me a global database of tree RFID tags allowing effective tracking would make Interpol’s and the UN’s life easier. These could be created by LEAF and given to local enforcement and forestry agencies, with initial supervision of their attachment to the tree or/and shipment of trees leaving ports and harbours. An international legal requirement of tracking timber shipments would be a further boon.


1. Green Carbon, Black Trade: Illegal Logging, Tax Fraud and Laundering in the World’s Tropical Forests. UNEP and Interpol. 2012.