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bumble bee on tree flower. © lava777/fotolia.com
March 2013

Trees have electric auras

What has been pootling in the realm of border sciences or even deemed to be esoteric fantasy is slowly coming to light. Plants do have electric auras, and they are used for communication between organisms.

A team around Daniel Robert at Bristol University conducted a series of tests that show how bumble bees make use of the electric charge of flowers. As insects fly through the air they acquire a positive electric charge. Plants, on the other hand, are grounded in the Earth and so have a negative charge.

The team in Bristol created a number of artificial flowers which were filled either with sucrose or with quinine, a substance bees don't feed on. These flowers smelled identical and the bees visited them randomly. But when some of these flowers were charged with a 30-volt-static electric field (typical for a flower of 30cm height) the bees detected the fields from a few centimetres away and visited the charged flowers 81 per cent of the time.

Further tests revealed that bees are influenced by the shape of the electric field as well. The bees preferred to visit flowers with fields in concentric rings, these were visited 70 per cent of the time compared to only 30 per cent for flowers with solid circular fields. It is speculated that flower plants developed differently shaped fields in the course of evolution to attract pollinators more efficiently.

When an insect visits a flower it transfers some of its positive charge, thereby incrementally changing the flower's field. A flower's decrease in pollen or nectar finds a quick and up-to-date monitor in its electric field, thereby informing the insects as they approach. [1]

Little is known about the electric properties of trees, although the first systematic measurements of trees were performed at Yale University already from 1943 to 1966, when Harold Saxton Burr recorded the bio-electrical fields of a sycamore and an elm tree which showed electric potentials varying up to 500mV [2]. In Europe, the only tree species that does not hibernate is yew (Taxus baccata) which at midwinter (21 December) can have an electric flow of 70 micro ampere per millimetre, at 0.833V. [3]

sources:
[1] Douglas Heaven, Electric plant auras guide foraging bees, New Scientist, vol. 217, no. 2906, p. 14
[2] Fred Hageneder, The Spirit of Trees, p. 32
[3] Fred Hageneder, Yew – A History, p. 69

world map showing degrees of solar radiation. © Wikimedia Commons
Jan 2012

All climate models questionable

In an article titled 'Include trees in climate modelling, say scientists' The Guardian reports that 'current climate models and projections may be inaccurate because measurements are based on guidelines that do not include the effects of trees on the local climate.'

It refers to a book which agroforestry experts at the World Agroforestry Centre (ICRAF) published in December 2011: How Trees and People can co-adapt to Climate Change.

'Trees can influence many of the climate factors predicted by modelling, and their effects should be added to climate maps…'

'"Following the guidelines of the World Meteorological Organization (WMO), global weather stations collect climate data on open ground — away from trees", says Meine Van Noordwijk, an editor of the book.' The WMO standards intentionally 'avoid tree canopy effects on the measurements.' – Why?

'"Unfortunately … climate scientists have not made much effort to quantify [the effects of trees]. By not looking at that, we are missing a large opportunity to understand how we can adapt."'

For six years now, climate scientists have ignored the call from Russian scientists to allow for the massive impact of continental forests on climate (READ MORE). Hopefully the new pressure from agroforestry will have an effect…

source: Dyna Rochmyaningsih, Include trees in climate modelling, say scientists: Climate models should include the effects of trees on the local climate, say agroforestry experts, The Guardian Environment Network, 16 January 2012

string: The real importance of the Amazon rainforest

'Forest Hero' Shigeatsu Hatakeyama. © Ryo Murakami/UNU
Dec 2011

Forests 'activate' coastal seas

Already decades ago, Katsuhiko Matsunaga, a marine chemist at Hokkaido University in Japan, discovered that when tree leaves decompose, they leech acids into the ocean that help fertilize plankton. And when plankton thrives, so does the rest of the food chain. [1]

This was put into good practice by Japanese fisherman Mr Shigeatsu Hatakeyama who inherited an oyster farm business from his parents. But the waters in Kesennuma Bay in Miyagi, Japan, had become unsuitable for oyster cultivation after an outbreak of red tide plankton. On a trip to France in 1984, Mr Hatakeyama saw healthy oysters in the Loire river estuary and noticed a vast deciduous broadleaf forest upriver. He made the connection and he realized the positive influence forests have on ocean ecology and biodiversity.

Back home, he held the first Mori wa Umi no Koibito (Forests are Lovers of the Sea) campaign in 1989: with other fishermen he planted broadleaf trees upstream along the Okawa River to reduce pollutants flowing into the sea. These afforestation activities became an annual event and have since gained momentum – so far, more than 50,000 trees have been planted. It has led to a region-wide proactive movement to preserve the environment, including water drainage regulation and promoting farming practices with less agricultural chemicals. [2] [3]

Mr Hatakeyama became known as 'Grandpa Oyster' after spending more than twenty years developing the forest that keeps the Okawa River clean and his thriving oysters healthy.
In 2009, he established another Forests are Lovers of the Sea programme which provides hands-on education for children, bringing them closer to the ocean and the forest.

He has now received a Forest Heroes Award from the UN International Year of Forests 2011 committee.

sources:
[1] Jim Robbins, Why Trees Matter, NY Times, April 11, 2012
[2] Asia & Japan Watch
[3] UN Forest Heroes Award

Iguazu Falls, Brazil. © gary yim/shutterstock.com
March 2010

The real importance of the Amazon rainforest

Peter Bunyard, the science editor of The Ecologist and of Science in Society, has published an article called 'The Real Importance of the Amazon Rain Forest'. He hopes to draw attention to the work of two scientists from the St Petersburg Nuclear Physics Institute who show to what unexpected extent the rainforests are responsible not only for the moist, fertile climate of South America and Central Africa, but the equilibrium of world climate.

The research by A.M. Makarieva and V.G. Gorshkov, the Russian scientists, challenges the established views of climatologists and renders all current computer simulations regarding 'global warming' incomplete and inaccurate. Hence they have been adamantly ignored by the scientific community.

Bunyard states that 'the implications of Makarieva and Gorshkov's thesis are enormous; essentially it means that South America cannot do without its rainforests' …and neither can we in the northern hemisphere.

READ MORE

source: Peter Bunyard, The Real Importance of the Amazon Rain Forest, ISIS Report, 15/03/2010
string: All climate models questionable!, Amazon deforestation fails to improve local life

veils of rain over forest landscape. © Dudarev Mikhail/fotolia.com
Oct 2008

Tree vapours cool planet

Forests store carbon and help in this way to prevent global warming. But they do more: scientists in the UK and Germany have now discovered that trees release a chemical that thickens clouds above them, which then reflect more sunlight and cool the Earth more sufficiently.

The scientists looked at chemicals called terpenes that are released from boreal forests across northern regions such as Canada, Scandinavia, Russia and Siberia. But other trees also produce terpenes so the cooling effect should be found in other regions too, including the tropical rainforests.

The terpenes react in the air to form tiny particles called aerosols. The particles help turn water vapour in the atmosphere into clouds. The particles released by pine forests, for example, double the thickness of clouds some 1,000m above the forests, which causes them to reflect an extra 5% sunlight back into space. 'It might not sound a lot, but that is quite a strong cooling effect. … It gives us another reason to preserve forests,' says Dominick Spracklen of the Institute for Climate and Atmospheric Science at Leeds University.

The research suggests that the destruction of old-growth forests could accelerate global warming more than was thought, and that protecting existing trees could be one of the best ways to tackle the problem.

source: David Adam, Chemical released by trees can help cool planet, scientists find, The Guardian, 31 October 2008

woman, taking a deep breath beneath trees. © Fotowerk/fotolia.com
May 2008

Trees improve human health

Trees release various beneficial chemicals. Some of these form aerosols which assist cloud forming and thickening and thereby regulate the climate (compare tree news: Tree vapours cool planet). Others are anti-bacterial, anti-fungal and anti-viral and thereby have beneficient effects on human health.

Forests also act as water filters in nature, capable of cleaning up various forms of toxic waste. Trees achieve this by cooperating with a dense community of microbes around their roots that biochemically clean water in exchange for nutrients, a process called phytoremediation. [1] (Microorganisms in the soil of pot plants also clean the air in rooms, see article at Tree World.)

Trees also counteract air pollution. A 2008 study by researchers at Columbia University found that children living on tree-lined streets are less likely to develop asthma. This study was conducted in New York City, where the leading cause of hospital admission for children under the age of 15 is asthma. Since more trees in urban neighbourhoods seem to correlate with fewer cases of asthma, and New York City counted about 500,000 trees outside of parks and private land in 2008, the Million Trees NYC tree-planting initiative developed, under the umbrella of the New York Restoration Project founded by actress Bette Midler. [2]

In Japan, on the other hand, the positive effects of trees on human health have been known for a very long time. Researchers have long studied a Japanese custom called 'forest bathing' (Shinrin-yoku) – which does not literally mean bathing but simply spending time in the woods. Breathing in volatile substances called phytoncides (essential oils), which are anti-microbial organic compounds derived from trees, invigorates the human organism. Forest time reduces the level of stress chemicals in the body, boosts the immune system and hence helps to ward off viruses, bacteria and even tumours. Various studies confirming this have been conducted by the Department of Hygiene and Public Health in Tokyo. [1] [3]

In Britain in 2001, the Department of Health sent out thousands of leaflets to all health authorities and hospitals, pointing out the health benefits of trees. The leaflet was called Sustainable Urban Forestry – Benefiting Public Health, and informed about the advantages for bedridden patients if they can see trees:

'They need less pain-relieving medication, they are better patients and they need to stay in hospital for a shorter period of time, so surrounding hospitals with trees can improve both healthcare and economic efficiency.'

Getting patients involved in tree-planting and care is another recommendation. 'Trees will also make staff feel less stressed.' [4]

Sources:
[1] Jim Robbins, Why Trees Matter, NY Times, April 11, 2012
[2] Jane Akre, Trees May Cut Asthma – NYC Study Finds, The Legal Examiner National NewsDesk, May 01, 2008
[3] Int J Immunopathol Pharmacol
[4] quoted in Tree News, issue 2, autumn/winter 2001. The leaflet was prepared by the National Urban Forestry Unit of the UK.

oldest spruce in the world: 'Old Tjikko' in Fulufjäll, Sweden. © Karl Brodowsky/Wikimedia Creative Commons
Feb 2008

The world's oldest spruce found in Sweden

In spring 2008, a 9,550 year-old spruce at Fulu Mountain in the Dalarna province of Sweden was proclaimed the 'world's oldest recorded tree'.*

* This might only be true if you swap 'world' for 'Europe' or 'tree' for 'spruce'. If you want the real superlative go to 'Pando', the gigantic American aspen colony in Utah.

The existing tree itself is actually not that old but under the crown of the (bonsai-sized) tree, scientists found four 'generations' of spruce remains in the form of cones and wood. Carbon-14-dating at a lab in Miami, Florida, showed the samples to be 375, 5,660, 9,000 and 9,550 years old respectively. 'Clear signs that they had the same genetic make-up as the trees above them' suggest, according to the Swedish scientists, that this tree had been alive all this time. Which is feasible because spruce trees are able to multiply with root-penetrating branches, in other words, they can clone themselves.

However, pre-dating the arrival of spruce in the region challenges the theory that the species came to Sweden from the east. Spruce is able to survive harsh conditions but would it have been possible for the seeds to travel 1,000 kilometres over inland ice that covered Scandinavia at the end of the last Ice Age?

Hence, Leif Kullman, Professor of Physical Geography at Umea University, suggests that spruce survived in places west or south-west of Norway and later spread north along the ice-free coastal strip. 'In some way they have also successfully found their way to the Swedish mountains.'

source: TreeNews, Issue 16, Spring/Summer 2009, p27;
Wikipedia: Old Tjikko

ice on Greenland (2009). © Halorache/Creative Commons
July 2007

Oldest DNA samples found on Greenland

The world's oldest DNA samples have been retrieved from beneath the Greenland ice sheet. Contained in sediments from the bottom of a 2km (1.2 mile) ice core they show that Greenland was covered in a dense conifer forest teeming with flora and fauna less than a million years ago.

Scientists extracted fragments of DNA estimated to be between 450,000 and 900,000 years old. The organisms they stem from include insects such as beetles, butterflies and moths, and pine, yew and alder trees. 'These correspond to the landscapes we find in eastern Canada and in Swedish forests today,' says Professor Willerslev of the University of Copenhagen, who led the research team. 'The yew trees reveal that the temperature during the winter could not have been lower than minus 17C and the presence of other trees shows that summer temperatures were at least 10C.'

It is the oldest authenticated DNA to be recovered from ancient biological material and represents a milestone for scientists trying to reconstruct past habitats eliminated by natural climate change. 'We've learnt that this part of the world was significantly warmer than most people thought," says Martin Sharp, a glaciologist at the University of Alberta.

source: Steve Connor, Oldest DNA samples found on Greenland, The Independent, 06 July 2007

prehistoric root system in the excavation field. © Nathalie Cohen
Oct 1998

Prehistoric forest discovered near London

Prehistoric forest discovered near London

A mile and a half of Neolithic prehistoric forest has been discovered on the south bank of the Thames at Erith on the outskirts of south-east London. The crumbling remains of oak, ash, alder, Scots pine and yew are thought to date from the Neolithic, and to represent a wooded island between two channels … Bronze Age pottery has been found overlaying the forest remains, and an early Neolithic wooden club, made of oak, about 2ft 6in long, which has been radiocarbon-dated to 3630-3350BC. The excavations of the Thames Archaeological Survey are directed by Mike Webber.

source: British Archaeology, Oct 1998

viruses. © psdesign1/fotolia.com
Oct 1998

Epidemics vs. intact rainforest

The destruction of the tropical rainforest is often accompanied by the outbreak of new unknown diseases. An unknown virus, for example, was discovered in the blood of the workmen who cut the road from Belém to Brasília through the jungle in 1950. Subsequently, 11,000 people fell ill with high fever and muscle pains. And the construction of the railtrack from Lima to La Oroya in Peru resulted in an outbreak of the so-called 'Oroya fever'. The origin of the Aids virus, too, is thought to lie in the tropical rainforest.

The high biodiversity of the rainforest also promotes a high potential for unknown viruses – which can be set free by the ecological destabilisation of these areas. In Latin America, the extinction of big cats and the expansion of agriculture led to a massive increase of rodents, and hence of the Machupo virus. Other epidemics, like the Rift Valley fever, can be traced to the spreading of huge cattle herds and the explosion of mosquito populations that often accompanies clearfelling. 'A change of host, for example from rodent to human,' says virologist Kurt Roth of the Georg-Speyer-Haus, an Aids research institute in Frankfurt, 'is favoured by a preceding mass increase of the virus population because the chances of successful mutations are growing too.'

source: GEO [German equivalent to National Geographic]