Model shows ‘waves of forest degradation’


An international team of researchers has developed a model that suggests degradation of tropical forests occurs in a series of “waves”, reports the BBC News website’s Mark Kinver.

High-value trees were felled in the first “wave”, followed by a wave that removed mid-value timber before the remaining wood was felled for charcoal.

The team hopes the model will help manage forests as vital carbon sinks and limit the loss of biodiversity.

The findings appear in the Proceedings of the National Academy of Sciences.

The researchers said an economic theory was used to provide a general model to predict patterns of tree loss.

This translates to a prediction that waves of forest degradation will emanate from major demand centres and expand into nearby forested areas, targeting resources in sequence, starting with those of highest value,” they wrote in their PNAS paper.

“Such a sequence of demand, linked to resource utilisation, has been demonstrated for unmanaged fisheries… but has not been shown for the exploitation of differently valued tropical forest products.”

The team used data collected in the area surrounding Tanzania’s largest city, Dar es Salaam, to see how far the degradation “waves” had travelled between 1991 and 2005.

“The first wave that emanates is high-value timber, and that is mostly used for export,” explained co-author Antje Ahrends, an ecologist at the Royal Botanical Garden, Edinburgh.

“There has been a massive demand for this in China, and this is where most of the timber ends up.”

Dr Ahrends said the first wave moved out from Dar es Salaam rapidly, averaging about nine kilometres each year, because the “timber companies had lorries and loads of people working for them”.

“For the firms, it is only worthwhile to stay in a forest when timber can be accessed relatively easily,” she told BBC News.

“So once it becomes not so easy to get hold of the rest, the companies generally move on.”

The first wave had already moved outside of the team’s study area, and Dr Ahrends estimated that it was already more than 200km from Dar es Salaam.

The second wave saw trees being felled for medium-valued timber, which was generally used in the city for construction and furniture.

“This is expanding very rapidly, in line with urban migration,” she explained. “The town has an average growth rate of about 7% each year, so there is – again – a rapidly growing demand for this material.”

The timber is harvested by local companies, again with lorries, allowing large volumes to be collected in a relatively short space of time. This resulted in this degradation wave to also cover about nine kilometres each year.

The third and final wave involved local people collecting wood to make charcoal for cooking.

“It’s the most destructive of all of the waves because charcoal burners would collect everything,” observed Dr Ahrends, who was based at the York Institute for Tropical Ecosystem Dynamics when she carried out this research.

“It is only worthwhile moving on once there are no sizeable trees left in the forest.”

As a result, the charcoal wave had moved relatively slowly – from 20km outside Dar es Salaam in 1991 to 50km away in 2005.

“It is the most difficult of the waves to tackle because it is very poor people who burn charcoal and their livelihoods depend upon it.”

“Targeting that wave would mean trying to provide alternative resources for cooking, and alternative incomes for people who burn charcoal.

Species loss

The team also developed their model to gauge what impact forest degradation had on “public good” services, such as carbon storage and biodiversity.

They did this by recording what species of trees were in a particular area of the study, and what size the individual trees were.

“This later enabled us to calculate species richness and also the amount of carbon those trees were storing,” Dr Ahrends said.

“We found that there was a very strong linear impacts; for example, tree species richness dropped to only 14 species-per-sample-unit close to Dar es Salaam, whereas it is more than 40 species in areas 200km away.”

Dr Ahrends suggested that the model could be used to understand the impact of forest degradation in other sub-Sarahan nations in Africa.

“This is because conditions are very similar: high levels of corruption, weak law enforcement and very rapid rates of urbanisation.”

She added that the team’s model could help policymakers who were looking at ways to limit deforestation rates.

“What is really important is to understand the pattern of degradation and the way it spreads,” she suggested.

“While we have a good understanding of deforestation – which is the complete clearance of a forest – it is much more difficult to measure degradation.

“So if you have this simple model, then you have a basic understanding of how degradation might spread… which may help you develop some prediction of where it might spread from and how far it might spread.”

Source: BBC News website

Date: 03/08/2010

Study links forest fires to climate shift


A warming climate will fuel larger, more frequent wildfires in the Sierra Nevada and other parts of the West, and the fires will contribute to climate change, according to a new study reported in Insurance Journal.

More than 20 international scientists, in the report published in the journal Science, said fire is not only a consequence of climate change but an important cause.

“Fire also influences the climate system. This is what we call a feedback,” Jennifer Balch, a fire expert at the University of California, Santa Barbara, told the Reno Gazette-Journal.

Scientists determined intentional deforestation fires, many set in tropical areas to expand agriculture or ranching, contribute up to a fifth of the human-caused increase in emissions of carbon dioxide, a heat-trapping gas helping to boost global temperatures.

The researchers called on the Intergovernmental Panel on Climate Change (IPCC) to fully integrate fire into its ongoing assessment of climate change.

Fire-climate feedbacks, they said, have been largely absent from global climate models.

“Extraordinary (fires are) occurring like a rash all over the planet,” said David Bowman, a forestry and wildlife expert at the University of Tasmania.

Fire of unprecedented ferocity swept across parts of Australia in February, killing about 200 people.

Similar fire activity can be expected elsewhere as the climate warms, including in the Sierra, where a 2007 blaze at Lake Tahoe destroyed 254 homes, scientists said.

“We are witnessing an increasing amount of so-called megafires,” said Thomas Swetnam, an expert on fire history and forest ecology at the University of Arizona. “Unfortunately, I think we are going to see more large fires in the western United States. The western United States is in a bull’s-eye.”

Swetnam was involved in a 2006 study that indicated increased fire activity is associated with increasing spring and autumn temperatures and an earlier spring snowmelt in western mountains.

That study found that wildfire frequency spiked to nearly four times the average experienced from 1970 to 1986, with the area burned more than six times previous levels.

The average length of the fire season increased by 78 days between 1987 and 2003 compared with 1970 to 1986, with fires starting earlier and burning later into the season.

Source: Insurance Journal

Date: 30/04/2009

Key role of forests ‘may be lost’


Forests’ role as massive carbon sinks is “at risk of being lost entirely”, the BBC’s Mark Kinver has reported top forestry scientists as warning.

The International Union of Forest Research Organizations (IUFRO) says forests are under increasing degrees of stress as a result of climate change.

Forests could release vast amounts of carbon if temperatures rise 2.5C (4.5F) above pre-industrial levels, it adds.

The findings will be presented at the UN Forum on Forests, which begins on Monday in New York.

Compiled by 35 leading forestry scientists, the report provides what is described as the first global assessment of the ability of forests to adapt to climate change.

“We normally think of forests as putting the brakes on global warming,” observed Professor Risto Seppala from the Finnish Forest Research Institute, who chaired the report’s expert panel.

“But over the next few decades, damage induced by climate change could cause forests to release huge quantities of carbon and create a situation in which they do more to accelerate warming than to slow it down.”

The scientists hope that the report, called Adaption of Forests and People to Climate Change – A Global Assessment, will help inform climate negotiators.

The international climate debate has focused primarily on emissions from deforestation, but the researchers say their analysis shows that attention must also be paid to the impacts of climate change on forests.

While deforestation is responsible for about 20% of greenhouse gas emissions from human activities, forests currently absorb more carbon than they emit.

But the problem is that the balance could shift as the planet warms, the report concludes, and the sequestration service provided by the forest biomes “could be lost entirely if the Earth heats up by 2.5C or more”.

The assessment says higher temperatures – along with prolonged droughts, more pest invasions, and other environmental stresses – would trigger considerable forest destruction and degradation.

This could create a dangerous feedback loop, it adds, in which damage to forests from climate change would increase global carbon emissions that then exacerbate global warming.

The report’s key findings include:

  • Droughts are projected to become more intense and frequent in subtropical and southern temperate forests
  • Commercial timber plantations are set to become unviable in some areas, but more productive in others
  • Climate change could result in “deepening poverty, deteriorating public health, and social conflict” among African forest-dependent communities

The IUFRO assessment will be considered by delegates at the eighth session of the UN Forum on Forests, which has the objective of promoting the “management, conservation and sustainable development of all types of forest”.

Co-author Professor Andreas Fischlin from the Swiss Federal Institute of Technology commented: “Even if adaption measures are fully implemented, unmitigated climate change would – during the course of the current century – exceed the adaptive capacity of many forests.

“The fact remains that the only way to ensure that forests do not suffer unprecedented harm is to achieve large reductions in greenhouse gas emissions.”

Source: BBC News website

Date: 18/04/2009

UK firm barcodes trees to save the world’s forests


Barcoding every tree in an African rainforest sounds as plausible as counting grains of sand on a beach, but this is exactly what one British company has set out to do, reports Kate Walsh for the Times.

Helveta, a technology firm based in Oxford, is developing a system for tracking timber that will help prevent illegal logging and could become a template for forest management all over the world.

Using a system of barcoding similar to that used by supermarkets for stock control, Helveta aims to tag all 90 million trees in 4.3 million hectares of rainforest in Liberia.

The marking process will allow customers in Britain and elsewhere to trace every timber plank or piece of garden furniture back to its stump.

The Liberian government has awarded the company a £1m, four-year contract to implement the system.

A 14-year civil war destroyed much of Liberia’s forestry sector, along with the country’s infrastructure.

At the height of the fighting, the country’s fragile forests were being stripped to pay for weapons. Niangon and Lovoa, high-quality timber used in furniture making and worth up to £180 a cubic metre, was sold to buy guns and ammunition.

Helveta claims its system of mapping is the only one in the world that can guarantee the “sustainability and legality” of timber.

Climate change is making the protection and management of forests a priority – the provenance of timber is therefore becoming “critically important” to retailers such as B&Q and Habitat, the company said.

“Our appetite in the West for ethically-sourced goods – whether it’s coffee or chocolate – is growing and retailers are responding to that,” said Derek Charter, Helveta’s project manager in Liberia.

“There is also a raft of different legislation being put in place – at EU and UK-government level – that will enforce the legality of timber on the retailer. In other words, if retailers cannot prove where the timber has come from, they could be penalised.”

The process of barcoding each tree – about one million of the 90 million tagged trees will actually be harvested – is fairly simple.

A 4cm plastic tag, which has a unique identity number, is hammered into the tree trunk. Only trees over 40cm in diameter can be tagged; anything smaller than that is protected.

After the tree has been felled, another tag (carrying the same identity number) is hammered into the stump.

“The barcode gives a record of where exactly the tree stands in the forest,” said Mr Charter.

“Ultimately, it will create a map of the forest. It also records the species and what that tree would be expected to yield. All this information is stored in our database in Reading.

“If you went into a furniture retailer on the high street and asked where a garden table came from, they will look at the ticket and say it is from a forest in Bolivia but they have no proof – that’s just where they have been told it is from or where the invoice was paid.

“With our system you could go to our website, type in the tree’s identity number and it will show you a map of Liberia and then zoom into the stump where your timber was harvested from. The current principle is that the country can use that information to market its natural resources to the buyer.”

The government hopes that the first tagged log will be exported before the end of the year.

Some conservationists have criticised Liberia’s plans to cut down trees – sustainably or not – instead of setting aside its rainforest for carbon offsetting.

Employment is the government’s biggest argument in favour of logging, together with the tax revenues it will generate.

It is estimated that the forestry sector could employ 10,000 people directly by 2012 and another 30,000-40,000 indirectly.

US Aid, the American development agency, together with the UN and the World Bank, have invested $20m in the country’s forestry sector to prevent a return to the days of illegal logging.

The result is that not a single log has been exported from Liberia since the lifting of the embargo three years ago.

Peter Lowe, forestry co-ordinator at the World Bank, said: “Liberia really has bravely taken the challenge to set regional standards in forest conservation.

“[Barcoding] is the most sophisticated system I’ve seen because it requires levels of transparency that don’t normally exist.”

Source: The Times newspaper

Date: 22/03/2009

Africa’s tropical forests ‘absorbing more carbon’


Trees across the tropics are getting bigger and offering unexpected help in the fight against climate change, scientists have discovered.

A report in the Guardian newspaper described how a study of the girth of 70,000 trees across Africa has shown that tropical forests are soaking up more carbon dioxide pollution that anybody realised.

Almost one-fifth of our fossil fuel emissions are absorbed by forests across Africa, Amazonia and Asia, the research suggests in the journal Nature.

Simon Lewis, a climate expert at the University of Leeds, who led the study, said: “We are receiving a free subsidy from nature. Tropical forest trees are absorbing about 18% of the carbon dioxide added to the atmosphere each year from burning fossil fuels, substantially buffering the rate of change.”

The study measured trees in 79 areas of intact forest across 10 African countries from Liberia to Tanzania, and compared records going back 40 years. “On average the trees are getting bigger,” Lewis said.

Compared to the 1960s, each hectare of intact African forest has trapped an extra 0.6 tonnes of carbon a year. Over the world’s tropical forests, this extra “carbon sink” effect adds up to 4.8bn tonnes of CO2 removed each year – close to the total carbon dioxide emissions from the US.

Although individual trees are known to soak up carbon as they photosynthesise and grow, large patches of mature forest were once thought to be carbon neutral, with the carbon absorbed by new trees balanced by that released as old trees die.

A similar project in South America challenged that assumption when it recorded surprise levels of tree growth a decade ago, Lewis said.

His study, he added, was to check whether the effect was global.

The discovery suggests that increased CO2 in the atmosphere could fertilise extra growth in the mature forests.

Lewis said: “It’s good news for now but the effect won’t last forever. The trees can’t keep on getting bigger and bigger.”

Helene Muller-Landau of the Smithsonian Tropical Research Institute in Ancon, Panama, used a commentary piece in Nature to suggest that the forests could be growing as they recover from past trauma.

“Tropical forests that we think of as intact [could have] suffered major disturbances in the not-too-distant past and are still in the process of growing back,” she said.

Droughts, fire and past human activity could be to blame, she added: “This recovery process is known as succession and takes hundreds or even thousands of years.”

The research comes as efforts intensify to find a way to include protection for tropical forests in carbon credit schemes, as part of a new global climate deal to replace the Kyoto protocol.

Lee White, Gabon’s chief climate change scientist, who worked on the new study, said: “To get an idea of the value of the sink, the removal of nearly 5bn tonnes of carbon dioxide from the atmosphere by intact tropical forests should be valued at about £13bn per year.”

David Ritter, senior forest campaigner at Greenpeace UK, said: “This research reveals how these rainforests are providing a huge service to mankind by absorbing carbon dioxide from our factories, power stations and cars.

“The case for forest protection has never been stronger, but we must not allow our politicians to use this as an excuse to avoid sweeping emissions cuts here in the UK.”

Source: Guardian newspaper

Date: 18/02/2009

Brazil announces 70% cut in deforestation


Brazil has announced a plan to reduce deforestation rates in the Amazon region by 70% over the next 10 years, the BBC News website reports.

The plan follows a call for international funding to prevent further loss of the Amazon rainforest.

This year, the rate of Amazon deforestation increased after falling for the past four years.

The new initiative by the Brazilians came as the UN’s latest round of climate talks began in the Polish city of Poznan.

Tasso Azevedo, head of the Brazilian government’s forestry service, said: “We can now adopt targets because we now have the instruments to implement them.”

He was referring to a new Amazon fund, where foreign nations are being encouraged by Brazil to contribute financially to the conservation of the vast Amazon region.

Last month, Norway announced its intention to support the fund, saying it will give $130m (euros 103m; £88m) next year, the first instalment of $1bn to be given over the next seven years.

However, Norway will only make each year’s donation on the condition that there has been a reduction in deforestation during the previous year.

The 70% figure is based up on averaging levels of deforestation in the 10 years up to 2005.

The new plan aims to see a reduction in deforestation of nearly 6,000 sq.km. per year, or about half the current annual rate of deforestation.

A crackdown on illegal settlements and increased policing in the Amazon region came earlier this year, following an estimated 3.8% increase in deforestation compared with the previous year.

Burning of the forests has contributed to increases in global atmospheric carbon dioxide levels, but Brazil’s Environment Minister Carlos Minc said the initiative showed the country was committed to reducing global emissions.

“Just in terms of avoided deforestation in the Amazon, the plan foresees a reduction of 4.8bn tons of carbon dioxide that won’t be emitted up to 2018 – which is more than the reduction efforts fixed by all the rich countries,” he said.

But environmental campaigners have said more needs to be done.

“The biggest Brazilian contribution to the fight against climate change is to bring deforestation to an end in the Amazon,” said Sergio Leitao, Greenpeace director of public politics in Brazil.

“In adopting timid targets the government is showing that it is going in the right direction, but at the wrong speed, because the problem requires urgent solutions,” he told the BBC.

“By connecting the reduction of deforestation to obtaining international resources, in a moment of economic crisis, the government has an argument ready for not achieving targets in the future,” Mr Leitao said.

Source: BBC News website

Date: 02/12/2008

Trees ‘grow faster, store more carbon’


In a press release, issued via Newswise, Mitchigan Technological University researcher Dr Andrew Burton suggested that moderate climate change was beneficial for northern hardwood trees.

In a very brief notice of the findings, reproduced in its entirety below, it offers a very basic explanation of how a slight warming changes the growth dynamics of the trees:

More than 20 continuous years of research into the effects of climate and atmospheric pollution on forest productivity in the Great Lakes region indicate that moderate increases in temperature with sufficient moisture and increased nitrogen deposition have extended the growing season in northern hardwood forests, causing the trees to grow faster and to store more carbon.

Dr. Andrew Burton, director of the Midwestern Regional Center of the National Institute for Climatic Change Research, can talk about his NSF-funded Michigan Gradient Study referenced above and the effects of temperature, moisture and acid rain on northern hardwood forests.

Tree Cover decided to attempt to find out more about this project and found an abstract for the project on the University’s website:

We will assess the degree to which temperature acclimation occurs in root systems of a variety of woody plants and determine if such acclimation is a short-term, direct physiological adjustment to warmer temperatures (days to months) or a longer term response to changes in nutrient, moisture and C availability and mycorrhizal status as the ecosystem adjusts to long-term warming (years).

Specific questions we will address include: Does rapid temperature acclimation occur in roots of large perennial woody plants? How do root biomass, root N concentration, and root respiration rates adjust to long-term changes in soil temperature and moisture and concomitant changes in N availability? How are rates of mycorrhizal infection influenced by the effects of warmer soil temperatures on host C balance and soil N availability? How do the short- and long-term responses of roots and mycorrhizae to warming and associated changes in soil nutrient cycling affect soil CO2 efflux and C availability for aboveground NPP? Are the interrelationships between warmer soil temperature regimes and C fluxes to and from roots and mycorrhizae adequately described by current ecophysiological models?

To understand both immediate and long-term effects, plots with 0 to 16 years of warming will be utilized. These include northern hardwood forests in Michigan, with warming to be initiated after a year of pre-treatment measurements; willow and alder in the shrub layer of a fen peatland in Michigan, with warming to be initiated in 2008; and mixed hardwoods at Harvard Forest that have been warmed since 1991, 2003 and 2006.

We will measure specific root respiration, root N concentration, root biomass, N mineralization, root N uptake, litter inputs, biomass increment, soil C content and mycorrhizal abundance, community composition and respiration. Treatments at the two Michigan locations include both soil warming and moisture manipulations, allowing us to examine the interaction of these two important global change factors.

We will know in the first year if rapid, physiological acclimation of root respiration occurs or if warming immediately alters mycorrhizal abundance. What may be of more importance are the amounts of C allocated to root respiration and mycorrhizal symbiosis that will exist in an ecosystem after N cycling, aboveground productivity, litter quantity, quality and decomposition, and microbial community composition and function have equilibrated to the altered climatic regimes. We will assess the interrelationships that exist between such processes and determine the factors that will ultimately control soil CO2 efflux and NPP in an altered climate.

However, there are no further details about the study’s findings, making it hard to know whether the project has completed gathering field data or whether this part of the research was ongoing. The abstract appears to have been uploaded on to the website in 2008.

It seems strange to release a statement saying “moderate climate change” was beneficial, especially when previous research papers have highlighted that forests are projected to responsed differently to a warming world, depending on what latitude they are located.

While there could be benefits to the region’s timber sector, it is seems bereft of key parameters – such as what extent of warming constitutes “moderate” warming, and to what degree is this warming projected to alter other factors, such as precipitation.

Also, in the context of the global carbon cycle, how does this degree of warming alter other carbon sinks – tropical forests, oceans etc – in  terms of sequestration; do we see a net increase or net decrease in the amount of atmospheric carbon being absorbed?

Looking forward to see more data on this interesting project being made available.

Source: MTU press release

Date: 17/10/2008

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