Using forests to manage carbon: a heated debate

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Tongass National Forest, Alaska.
Joseph/Flickr, CC BY-SA

Michael Tausz, University of Birmingham and Rob MacKenzie, University of Birmingham

The best way of managing trees and forests for climate change and accounting for contributions of forests and forestry activities in carbon budgets remains hotly contested. Forests can either take up carbon dioxide (CO₂) or release more CO₂ into the atmosphere. Wood can substitute fossil fuels or energy-intensive materials, but forests are also large carbon reservoirs that add emission peaks if disturbed.

The atmospheric concentration of CO₂ has increased from a pre-industrial 280ppm (volume parts per million) to just above 407ppm – and will reach 550ppm by 2050. As the main greenhouse gas, CO₂ drives human-induced climate change. Most global CO₂ emissions come from burning fossil fuels, but net deforestation still adds about five billion metric tons of CO₂ per year.

Deforestation in Nigeria.
Foreign and Commonwealth Office, CC BY-ND

Global deforestation is mainly determined by large-scale clearing of tropical forests, still progressing at some 3m hectares a year. In contrast, European forests have been cleared over many centuries and are now expanding, having grown by about 11m hectares since 1990. Regrowing forests on deforested land creates carbon sinks which remove CO₂ from the atmosphere.

Wood can reduce carbon emissions by being substituted for materials such as cement or metal, and replacing fossil fuels in energy generation. The CO₂ released when wood is burnt can be recouped by planting new trees, making wood a renewable source of energy.

Accounting for forests and forestry activities in carbon balance sheets is a controversial task. For example, the amount of timber harvesting that can be seen as sustainable is regularly contested, even among European countries. The increasing use of wood fuels in energy generation is also creating debatable outcomes.

Such controversies often boil down to a choice between locking up the existing carbon reservoirs in trees and forests, or growing forests into wood products that replace fossil fuel-intensive alternatives.

Young, rapidly growing forests remove atmospheric carbon quickly, but have relatively small carbon reservoirs. Ageing forests capture carbon at decreasing rates, but build up large carbon reservoirs in biomass and soils. When an older forest is logged, not only the wood is removed, but carbon from unused biomass and soil is also released back into the atmosphere, creating a “carbon debt”. Especially large, old trees store most carbon, but are often over 100 years old. Repayment of the carbon debt may, therefore, take a long time.

Theoretically, older forests reach an equilibrium, when carbon taken up into new growth is balanced by carbon released through decomposition processes. But this has been proved wrong. Even 800-year-old forests still continue to take up carbon, and, perhaps more surprisingly, individual large, old trees maintain high growth rates, too. Old forests are not only large carbon reservoirs worth maintaining, but actively continue to capture atmospheric carbon.

Protecting older forests

FACE experimental installation.
John James, University of Birmingham, Author provided

There are risks. First, we do not know for how long mature forests will continue to soak up additional CO₂ as atmospheric concentrations increase further and push forest ecosystems even faster into unchartered territory. To study mature forests in a future atmosphere requires large-scale experiments such as the Free Air CO₂ Enrichment (FACE) programme initiated by the Birmingham Institute of Forest Research. Only such elaborate (and rather expensive) technological marvels can supply the real-world data needed to answer this question.

Second, large-scale disturbances such as bushfires, drought dieback or pest epidemics, stop trees from taking up more carbon and also mobilise carbon from soils and decaying or burning trees. For example, forests in British Columbia, Canada, have turned from a carbon sink to a net carbon source following large-scale outbreaks of a native pine beetle. Very little is known about how environmental changes and rising CO₂ affect the vulnerability of trees and the resilience of forest ecosystems.

On the upside, in a country with low forest cover such as the UK, any sensible reforestation (avoiding bogs) is beneficial for carbon balance. Yet managing forests solely for their carbon benefit would miss the point. Especially older trees and forests provide a host of services, including biodiversity, flood mitigation, clean water and human well-being benefits.

The ConversationAny policy incentives must aim at balanced outcomes for all forest goods and services. Incentives that commodify one service but not others, too often create unintended consequences. Where forests are concerned, such mistakes are expensive, because it takes a long time to reverse adverse effects on old trees and forests.

Michael Tausz, Director of Birmingham Institute of Forest Research, University of Birmingham and Rob MacKenzie, Professor of Atmospheric Science, University of Birmingham

This article was originally published on The Conversation. Read the original article.


Antarctica: Ozone Hole Healing

The link below is to an article that brings some good news regarding our environment – the ozone hole over Antarctica is healing and should continue to do so. This is a story that shows we can manage the environment in a much better way when nations actively work together to solve the problems we face.

For more visit:


Peter Garrett, Australia’s Minister for the Environment, Heritage and the Arts, today released a report on the biodiversity, ecosystems and social and economic uses of the oceans of northern Australia. The report entitled ‘The North Marine Bioregional Profile,’ brings together and explores the available knowledge of the Arafura and eastern Timor Seas, from the Northern Territory/Western Australia border to Torres Strait, including the Gulf of Carpentaria.

The report is expected to assist the government to better understand and protect our marine environment, conserve biodiversity and determine the priorities in our marine conservation efforts. It will also assist industry to better plan and manage their activities in the region.

A Marine Bioregional Plan for the region covered in the report is expected to be handed down in 2010. In total there will be five plans covering Australia’s marine regions.

View The North Marine Bioregional Profile at:

BUSH HERITAGE AUSTRALIA – Update September 2008

One of the groups I have a lot of time for in Australia and one which I am planning to support in a more active way in the New Year (once I get back on my feet so to speak) is Bush Heritage Australia.

Bush Heritage Australia is actively seeking to protect 1% of Australia by 2025, ensuring the protection of our unique flora, fauna and wild places. This is done through purchasing land by money donated to it by those wanting to protect the Australian environment and natural heritage. Bush Heritage currently owns some 1 million hectares, meaning it needs to acquire a further 6 million hectares to obtain its 2025 goal.

In September 2008, Bush Heritage Australia purchased the 8 100 hectare Edgbaston Station, 140km north-east of Longreach in Queensland for 3.5 million dollars. In doing so, Bush Heritage has ensured the survival of Australia’s most endangered and smallest freshwater fish species, the Redfin Blue-Eye Fish. This region is the only location in which this fish species now lives.

But it is not only the Redfin Blue-Eye Fish that will be protected by the purchase of this property as this region and the springs found on the property is the only known habitat for several other species of fish, snails, plants and a crustacean.

The springs on Edgbaston Station are located in the upper catchment of Pelican Creek which flows into the Thompson River and Lake Eyre. There are some 50 artesian springs on the property, supporting a large diversity of life.

The 3.5 million dollars required for the purchase of Edgbaston Station included 1.324 Million dollars from the Australian government’s Maintaining Australia’s Biodiversity Hotspots program and donations from the Queensland Department of Natural Resources and Water and the Queensland Department for Sustainability, Climate Change and Innovation.

Bush Heritage will be working alongside of the Iningai people, who are the traditional owners of the land on which Edgbaston Station is located, to manage the property.

For information on what you can do to assist Bush heritage Australia or to get more information on any of the reserves managed by Bush heritage Australia visit the web site below.