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forest fire. @ Peter J/
July 2012

Forest fires and their causes

The summer of 2010 became a 'once a century' disaster for Russia: the country had to fight over 600 severe forest fires, more than 50 people died. At the height of the incineration almost 200,000 hectares (494,000 acres) were aflame. In the following year, too, disastrous fires swept over vast areas [1]. And in summer 2012 again: in the Amur area alone more than two million hectares (five million acres) of forest were destroyed [2].

This has, of course, something to do with a global trend for higher temperatures that also wipes out eucalyptus forests in Australia, causes a prolonged drought in the southwest of the US, killing over five million urban shade trees in 2011 in Texas alone [3], and has caused even two 'once a century' droughts in the Amazon Basin. But insiders know that the heavy forest fires in Russia are no surprise but rather the quittance for a neglected national forest management: a few years ago, the new national forest law abolished the majority of local forestry offices. How the risk of forest fires is enhanced by forest mismanagement has been shown by recent studies in the USA.


Weltkarte mit Waldbränden

composition of satellite images with overlaid graph of forest fire frequency (2010)
red: very often, yellow: most often

© DPA / NASA / GSFC / MODIS Rapid Response


The USA too are struggling with ever more severe and bigger fires, mainly in the Southwest. Arizona, New Mexico and Texas have become so dry that huge, explosive fires consumed millions of acres of vegetation in the summer of 2011. The role of 'climate change' in this is still unclear, the more immediate cause seems to be the intermittent weather pattern called La Niña. What experts do see is that some areas that are burning this year may never return as forest — they are more likely to grow back as heat-tolerant grass or shrub lands. It is also becoming clear that the wide-spread method of clear-felling contributes to wildfires because the resulting landscape of brushwood and young trees is more susceptible to drought and catching a spark than the old trees with their developed roots and fire-proof bark.

There is also an emerging scientific consensus about another form of forest mismanagement: by suppressing the (natural) mild ground fires that used to clear out underbrush and limit tree density, many US forests are now hopelessly overgrown with brushwood. During droughts, such areas become tinderboxes. In some areas the dense brushwood has become so high that fires also damage the crowns of the old trees – which had been safe from most fires when the forests had been managed by nature.

The government agrees that many forests throughout the West need to be thinned, and some environmental groups have come to agree too. But the small trees and brush have little commercial value, especially in a weak economy, and funding for the thinning is thinning itself. For the time being, the Forest Service can treat only small sections of forest that pose the biggest threats. [4]

[1] Spiegel Online, Juli 2011 and topic overview (both German)
[2] Spiegel Online, Juli 2012 (German)
[3] Jim Robbins, Why Trees Matter, NY Times, April 11, 2012
[4] Justin Gillis, With Deaths of Forests, a Loss of Key Climate Protectors, NY Times, Oct 1, 2011

large buttressed tree in primary rainforest in Ecuador. © Dr. Morley Read/
Jan 2012

World's biggest trees disappear

Long-term studies in Amazonia, Africa and Central America show that proportionally, the biggest and oldest trees of the world vanish more rapidly than the younger tree populations.

Big trees may comprise less than 2% of the trees in a forest but they can contain 25% of the total biomass! They are vital for the health of whole forests because they produce large amounts of seeds. 'With their tall canopies basking in the sun, big trees capture vast amounts of energy. This allows them to produce massive crops of fruits, flowers and foliage that sustain much of animal life in the forests. Their canopies help moderate the local forest environment while their understory creates a unique habitat for other plants and animals,' says William Laurance, a research professor at James Cook University in Cairns, Australia.

But after clearfelling around them, 'their tall stature and relatively thick, inflexible trunks, may make them especially prone to uprooting and breakage near forest edges where wind turbulence is increased.'

Another cause for the disappearance of the ancients is fragmentation of forests, caused by roads, farms and settlements. 'Fragmentation of the forests is now disproportionately affecting the big trees,' says Laurance. 'Not only do many more trees die near forest edges, but a higher proportion of the trees dying were the big trees.'

Droughts and global warming are another problem: 'In cloud forests, big trees use their branches and crowns to rake the mist and capture water droplets. Recurring warmer weather,' however, seems to 'push clouds up to higher elevations depriving them of sources of moisture'.

Big tree species also disappear because their seedlings don't find favourable growing conditions anymore. After human intervention, aggressive shrubs may invade the forest floor or benevolent fungi may be driven out by pathogenic species. And seedling and young tree mortality rates rise due to warm winters which fail to kill pests.

New pests and diseases also spread due to human trade in plants and timber products. In the 1960s and 70s, the peak of the Dutch elm disease which had spread globally via infected timber, killed the majority of the old elm trees of the world. And now, new and often non-native organisms and bacterial infections are threatening oak, ash and other species, while North America's ancient alpine bristlecone pines (Pinus longeava; the oldest trees in the world) are falling victim to a voracious beetle and an Asian fungus (see Jim Robbins, Old Trees May Soon Meet Their Match, NY Times).

source: John Vidal, World's giant trees are dying off rapidly, studies show, The Guardian, 26 Jan 2012

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

Logo der Pan-African Agency of the Great Green Wall
June 2010

The Great Green Wall of Africa

The Great Green Wall (French: Grande Muraille verte) Spanish Gran Muralla Verde is a project to halt the spread of the South Sahara. The transcontinental belt is planned to be 15km (nine miles) wide and 7,775km (4,831 miles) long and will be made completely of trees. This equals the reforestation of 15 million hectares of land.

The project is held by the African Union and funded by the Global Environment Facility (GEF)*. An inter states organization was established to effectively implement the project in each of the eleven member states.

* The Global Environment Facility (GEF) is an independent financial organization uniting 182 member governments, in partnership with international institutions, nongovernmental organizations and the private sector, to address global environmental issues. According to their website, they are the largest funder of projects to improve the global environment, having allocated US$8.8 billion, supplemented by US$38.7 billion in co-financing, to more than 2,400 projects in more than 165 countries.

Landkarte Sahel

On 17 June 2010, the GEF announced that Africa's green barrier will be funded by a US$119 million grant. The project had long been searching for funding: it had begun to take shape in 2005, the idea first appeared in 2002 and can be traced back to projects fighting desertification in Burkina Faso under president Thomas Sankara. Inspirations are the (more decentrally organized) Green Belt Movement initiated by Nobel Prize winner Wangari Maathai, and the Green Wall of China (see tree news Jan. 2010).

source: Great Green Wall website

Iguazu Falls, Brazil. © gary yim/
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.


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

clearfelling area in Brazil. © guentermanaus/
June 2009

Amazon deforestation fails to improve local life

A new study by the department of life sciences at Imperial College London (and published in Science this month) undercuts the persistent argument that deforestation in the Amazon leads to long-term development of the local economy and social conditions.

Doubtlessly this seems to be the case temporarily: logging creates jobs, the new roads can give better access to education and medicine, and newly available natural resources in a cleared forest area attract investment and infrastructure. But once the timber and other resources dry up, things change again! 'A lot of the agricultural land is only productive for a few years,' says Rob Ewers, a member of the study team. 'On top of that you tend to have much higher populations because a lot of people have been attracted to the area.' This higher population has to survive on ever-dwindling local resources, which pushes the standard of living right down again. After the loggers have gone, development quickly falls back even below national average levels.

Every year, around 1.8 million hectares of rainforest are destroyed in the Amazon — a rate of four football fields every minute. Deforestation causes 20% of the world's greenhouse gas emissions. The Amazonian rainforest is one of the most biodiverse regions in the world, and guards against climate change by absorbing CO2 and maintaining geochemical cycles.

'Slashing and burning rainforest to make way for cattle ranches or soya farms is simply not sustainable, because profits are short-lived and the big companies simply move elsewhere. Instead we need sustained international funding to protect this massive natural resource, to make trees worth more alive than dead.'

Fact is: Trees already are worth more alive than dead, always have been, but word hasn't got round yet.

source: Alok Jha, Amazon deforestation leads to development 'boom-and-bust, The Guardian, 11 June 2009

string: The real importance of the Amazon rainforest

old cedar in Lebanon. © AFP Photo/Ho
Feb 2009

Cedar of Lebanon on the Red List

An undated handout picture released by the press office of the Shouf Cedar Nature Reserve on February 2, 2009 shows snow covering a cedar tree in the Baruk forest in the mountainous Shouf area southeast of Beirut.

Lebanon's majestic cedar trees have withstood the test of time for centuries but 'climate change' is threatening the country's most treasured symbol. Or rather: Man's destruction of the expansive forests of Lebanon and the subsequent effects on regional climate now threaten the last remaining pathetically small cedar stands with drought and extinction.

Used by various civilisations throughout history for their strong and durable wood, Lebanon's last remaining cedars are now on the International Union for Conservation of Nature's 'Red List' as a 'heavily threatened' species.

veils of rain over forest landscape. © Dudarev Mikhail/
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