An experiment that pumps carbon dioxide into groups of trees growing outdoors, designed to test how forests will respond to global warming may be ended by the US Department of Energy.

This is not a nefarious plot to squash the results of global warming research, but a genuine disagreement among two groups of scientists over how to proceed in climate change research.

The US Department of Energy has funded nearly 10 years of research at Duke Forest in Durham NC, Oak Ridge National Laboratory in Tennessee, and Harshaw Experimental Forest in Wisconsin. At each forest, rings of plastic pipes release carefully measured amounts of CO₂ into the air around groups of trees.  The experiment is known as FACE, for Free Air Carbon dioxide Enrichment.

Results so far indicate that forests respond to the extra carbon dioxide, an essential plant nutrient, by increasing growth. However, unless the forests are on fertile ground, growth is concentrated in short-lived plant parts like leaves or needles and fine roots. These parts die and decompose, releasing their carbon back into the atmosphere. When fertility is higher, trees may retain more of the carbon in wood. However, fertility experiments are not yet complete.

Project scientists believe that a few more years of data are needed to determine the effects of soil fertility on the ability of trees to sequester carbon.  However, DOE scientists believe that the experiment has run its course and that it is time to sample the trees and soils as a final measure of the long-term impacts of the experiment.

Richard Norby, who oversees the experiment at Oak Ridge, said “"This comes up in all sorts of long-term experiments — when is the right time to say, `Enough,’ There’s no good answer to that."

Picture: Duke FACE Experiment, courtesy of Duke University

Sources:

• Duke FACE
• Oak Ridge FACE
• Aspen FACE
• The Associated Press: Gov’t wants to change course of forest experiments

Earthworms can change the chemistry of carbon in forest soils and litter. Researchers at the Smithsonian Environmental Research Center are trying to figure out the impact of earthworms on forest soils, and how they may change soil chemistry.

Although we may think that earthworms are everywhere, they were actually introduced into North America by early European settlers, and have slowly spread out as people settled more areas.  I remember digging in Adirondack soils and finding earthworms only right around lakes and ponds, where they had been carried by fishermen.  Earthworms spread very slowly – on their own, they would only spread about 200 km in the 10,000 years since the last glaciers wiped out existing soils.  Most earthworm movement is by people carrying bait or moving soils in nursery material.

The impact of earthworms on carbon in soils is not obvious.  Earthworms consume leaf litter and carry organic matter deep into the soil.  Their work could increase carbon deep in the soil. But since they also consume leaf litter, they may strip the insulation off soils and increase temperatures, causing loss of carbon to microbial respiration.

Earthworm action has profound effects on soil processes. The Smithsonian project should help us understand their impacts on carbon storage in soils.  Since soils can store vast quantities of organic carbon, and could offset a lot of mankind’s industrial carbon dioxide emissions, understanding the role of earthworms is important.

The earthworm project is a joint effort between Purdue University, the Smithsonian, Johns Hopkins University and the University of Utrecht.

Picture: The earthworm, Lumbricus terrestris. Picture courtesy of Purdue University.

Links:

• Earthworm activity can alter forests’ carbon-carrying capabilities- Purdue University
• Earthworms, P. Bohlen 2002 – chapter from Soil Encyclopedia. Archbold Biological Station. (pdf)

Global warming is contributing to the increased frequency of forest fires in the American west. A new study by the US Forest Service shows that hot fires in western forests consume soil carbon and nitrogen, reducing the ability of soils to store carbon and reducing soil fertility.  This is a potential feed-forward effect: increasing temperatures due to carbon dioxide in the atmosphere increases fire frequency and intensity, and high intensity fires convert soil organic carbon to carbon dioxide, increasing global warming.

The new study was a fortunate outcome of an unfortunate event: the 2002 Biscuit Fire, which burned about 500,000 acres in southwest Oregon, burned research plots of an ongoing study of forest soils. That meant that there were samples of soils available before and after the fire as well as pre-and post-fire plots measuring tree and shrub growth. Bernard Bormann, the study’s lead investigator, said “Losing our experiment in fire was hard, but the opportunity to better understand fires as a dominant ecosystem process has been very exciting.”

The Biscuit Fire burned soils at more than 1300 F, converting soil organic matter into carbon dioxide, nitrogen oxides and water vapor. Soils lost 10 tons per acre of carbon and 450 to 620 pounds per acre of nitrogen. These losses were higher than estimates from previous studies.  Loss of nitrogen to this degree would take at least a century to recover, in the absence of nitrogen-fixing plants.

The loss of soil productivity means that replacement forests may grow very slowly for long periods. These new forests would not be a vigorous sink for carbon sufficient to offset carbon lost from the soil for many years. The exact balance between carbon loss from the fire, both in the standing tree crop and soils, and the rate at which replacement forests will take up carbon from the atmosphere is not known.

Sources:
Press Release from Pacific Northwest Forest Experiment Station – When it comes to forest soil, wildfires pack a 1-2 punch.
Bormann, BT, Homann, PS, Darbyshire, RL, Morrissette, BA. 2008. Intense forest wildfire sharply reduces mineral soil C and N: the first direct evidence. Can. J. For. Res. 38:2771-2783. doi 10.1139/X08-136.

Old growth temperate forests are an important global carbon sink, soaking up CO₂ at much higher rates than previously thought.The dogma for many decades has been that once forests become mature, they have such a large volume of non-green respiring (and CO₂ releasing) tissue that they do not accumulate carbon.As a result, old growth forests have been left out of discussions of carbon storage and sequestration.

Sebastiaan Luyssaert of the University of Antwerp, Belgium and his colleagues have shown that in forests from 15 to 800 years old, the net carbon balance, including soils, is positive.  That means that forests accumulate carbon regardless of age. 

Luyssaert found that boreal and temperate forests of the northern hemisphere sequester about 1.3 gigatonnes of carbon per year.  Disturbance of these forests would probably result in net release of CO₂.

This research, if borne out by further studies, should provide strong motivation for forests of all ages to be included in carbon sequestration schemes. That means that owners of forests should be able to get income through the sale of carbon credits, and these owners will have an incentive for forest protection and conservation.

Links:
Lysseart et al in Nature (sub. required)

Mongabay article on old growth

A private company, GreenTrees, is creating long-term contracts with landowners in the Lower Mississippi River Alluvial Valley, including Western Kentucky, to plant forests of cottonwood and other hardwoods. The purpose of the project is to create value through a combination of biomass production for industry and carbon sequestration opportunities. Carbon sequestration will create income streams through trading in carbon cap and trade markets.

In exchange for leasing the land to GreenTrees, landowners receive up-front payments, timber harvest income, recreational income, carbon-based income, and appreciating property values, as well as federal and state conservation incentives and payments.  Landowners can engage in these kinds of activities on their own, but they can’t tap into the up-front income offered by GreenTrees.

The Lower Mississippi River Alluvial Valley was a richly forested region until the 20th century, when bottom-land farming of soybeans cleared vast areas of land.  These lands are in the long run more valuable for carbon storage and watershed protection than crop production.

Stay tuned for more information on this interesting development.

Green-Trees.com

Cross posted at Sustainable Kentucky and Tree Trends.

A very important article from Joe Romm at Climate Progress this morning. Evidence is growing that methane in the atmosphere is increasing, and methane is a powerful greenhouse gas (20 times the heat absorption of CO₂ One source of methane may be deep sea-bed deposits that are released as the Arctic Ocean warms.   Joe points out that the evidence is preliminary until the research is published in a peer-reviewed journal, which is planned.

As a general recommendation, if you are interested in the science and politics of climate change, Joe’s Climate Progress blog is the most reliable source of information available.

Climate Progress » Blog Archive » Has runaway climate change begun?

Cross posted at Sustainable Kentucky and Tree Trends.

I’m giving a keynote speech at the Kentucky Governor’s Conference on the Environment.  Notes in preparation for the talk, which will include some discussion of forests and soils for carbon sequestration are at Sustainable Kentucky.

Andrew Revkin  at Dot Earth has a nice article about the proposal by Al Gore and Wangari Maathai to include forest preservation in carbon-trading markets designed to curb greenhouse gas emissions.  Gore and Maathai, both Nobel Peace Prize laureates for their conservation work, are promoting the work of the Avoided Deforestation Partners.

Tropical forest conversion to other uses currently accounts for about 20% of the world’s carbon budget.  In the Kyoto Protocols, the first plan to reduce world carbon emissions, forests received little attention, mainly because of opposition from environmental groups like the World Wildlife Fund and Greenpeace.  These organizations feared that counting tropical forests in carbon credit schemes might take pressure off major greenhouse gas (GHG) producers to reduce their own emissions. There was also concern that carbon credits extended to forest plantations might promote clearing of native forests. WWF has backed off that original position and now acknowledges that carbon credit trading could help conserve tropical forests.

Creating a significant dollar value for keeping tropical forests intact may provide governments and land owners with sufficient incentive to overcome the current incentives to clear tropical forests.  These incentives include profits from illegal logging and the high price for palm oil. Oil palm plantations have replaced large areas of lowland tropical forest throughout Southeast Asia, and the exploding biofuels market is putting market pressure on palm oil producers to expand their operations. Lowland forests, especially the kerangas (peat and heath forests) are critically threatened resources, store vast amounts of carbon and become major carbon sinks when converted to oil palm or other uses.

The challenge in placing dollar values on carbon storage in tropical forests, and paying for tropical forest conservation, is ensuring that the money gets to local people and that corruption can be overcome.  Malaysia and Indonesia have strong forest conservation laws on the books, but they are unenforceable due to corruption, with money flowing from forestry and oil palm interests to local and national government officials.  There has to be sufficient income to national governments from carbon trading credits to overcome the economic incentives that lead to corruption.  If money flows only to national governments and corporate interests, and does not benefit local people, any scheme will fail.

The solution to these problems is the same as the solution to the problems of sustainable forestry: reputable third-party certification.  Third party verifiers can produce management plans and provide evidence to carbon credit buyers so that the system can be trusted.

Pervasive corruption throughout the tropical countries that could most benefit from carbon credit purchases will be difficult to overcome, especially in countries like Indonesia with a weak central government and widespread poverty.

I took the photographs below in 1984 in West Kalimantan, Indonesia, showing the vast Kerangas (peat swamp and heath forest) of lowland Borneo in 1984. Most of this forest is now gone. Illegal logging remains rampant.  More pictures are at my photography site.

Links:

Two Nobelists Call for Forest Carbon Market – Dot Earth Blog – NYTimes.com

Avoided Forest Partners

Borneo Forests at Mongabay

Research by Peter Curtis (Ohio State University) and colleagues shows that northern Michigan forests can store an average of 0.65 tons C per acre per year. This rate of storage is higher than earlier estimates such as those used to develop the Kyoto Protocol, and is consistent with other recent studies that show that temperate forests are more efficient carbon sinks than previously thought.

The use of forests as purchasable carbon offsets will become more attractive as we learn more about how much carbon forests can store. However, there is so much variation in the factors that influence carbon storage in forests that prolonged, broad research like that discussed in this article will be needed at many more locations.

Links:

Press release: Scientists Point To Forests For Carbon Storage Solutions

Research Paper:

Christopher M. Gough, Christoph S. Vogel, Hans Peter Schmid, and Peter S. Curtis. Controls on Annual Forest Carbon Storage: Lessons from the Past and Predictions for the Future. 2008. Bioscience 58(7): 609-622.

Cross posted at Sustainable Kentucky/Green Kentucky