November 17, 2007

Hurricane Katrina's greenhouse gas legacy

Hurricane Katrina's legacy is not just the flooding of New Orleans and the destruction of coastal Mississippi. It is also responsible for damaging five million acres of forests - an area the size of the state of Massachusetts. For comparison, the destructive power the 1980 eruption of Mt. St. Helens wiped out 150,000 acres of forests (less than 4% of the forest destruction reach of Katrina).

In a front page article of the Los Angeles Times, Thomas Maugh II and Karen Kaplan reported on new research results by Tulane's Dr. Jeffrey Q. Chambers that has appeared in Science magazine. By using spectral analysis comparisons of before (2003) and after (2006) imagery of the region made by NASA's Landsat V satellite (click to enlarge image above), Chambers and his research team has made a number of alarming findings about the carbon footprint of this very destructive hurricane.

What is the greenhouse gas consequence of all that wasted biomass rotting and decaying?

Left in place without removal, the carbon of the trees will continue to decay for decades. Roughly 50% of the content of trees is carbon. The emissions from decay will contain methane and carbon dioxide. According to Dr. Chambers' analysis, 367 million tons of carbon dioxide will be emitted - which is about the same amount as is absorbed by all U.S. forests in a year. It is also a total that exceeds the combined emissions of national forest fires for an entire year.

What is the time frame for removal?

As it decays, the woody biomass becomes harder to access and harder to remove. Even with modern equipment, it is easier to assess, plan, and harvest standing trees than those lying on the ground at some progression of decay. Besides the remaining obstruction of hurricane-damaged logging roads in the area, foliage regrowth has already begun which makes logging access more difficult.

Should the drought conditions of the South persist, the dead biomass represents a significant fire threat which would add significant amounts of new greenhouse gas and particulate matter emissions to the atmosphere and further complicate restoration.

What will the new forests look like if left to natural regeneration?

According to the Times article, "Chambers and his colleagues said the deforested land, once covered with native species such as longleaf pine, oak and cypress, is being taken over by invasive species that are change the ecology of the area. One of the most prolific, the Chinese tallow, oozes a milky, toxic sap that creates an inhospitable environment for insects, birds and small animals."

How can we pay for forest restoration?

According to Dr. Thomas Bonnicksen of The Forest Foundation, the a privately financed restoration of the forests is straightforward. "Sell the logs to sawmills to be turned into wood products, and use the revenue generated to pay for removing the slash left behind and replanting the forest. Replant native trees in a patchy mosaic so the forest develops naturally. This includes leaving enough snags and logs for wildlife habitat, and returning a few years after planting to remove competing brush so trees grow quickly and are protected against future wildfires."

Who would administer the forest restoration program?

There is a federal committee called the Woody Biomass Utilization Group that includes forestry, energy, and wildlife experts from several departments of government - the Departments of Energy, Agriculture/Forest Service, and Interior. They also have a subgroup studying Disaster Debris that works with FEMA and Homeland Security in an effort to establish and coordinate federal remedial response to environmental disasters like Katrina, floods, tornadoes, and megafires throughout the country.

When asked what the biggest hurdle was to the implementation of harvesting and reforestation programs, Ron Vineyard of the Forest Service responded "infrastructure." By that he meant that there needs to be more sawmills, power plants, forest products companies, and biorefineries who can take possession of the woody biomass harvested from the disaster zones. The carbon would be sequestered in forest products like lumber, paper, and biochar while carbon-neutral bioproducts like ethanol, alcohols, chemicals, and bioplastics could be cleanly produced to reduce the use of carbon-positive petroleum byproducts.

Unfortunately, many of companies of the pre-existing infrastructure have been damaged from the hurricane, too, and the timberland owners of the region are likely to sell their lands to developers rather than pay to reforest their lost inventories. That will not make environmentalist groups happy who recognize the need to keep our forests large and healthy as carbon sinks to mitigate global warming.

Government action is needed now

There is no possible way that the federal agencies - who are already coping with fire-fighting, humanitarian rescue efforts, and capital restitution from each year's mounting ecological catastrophes - can pay for the scope of immediate remedial action needed. Political leadership and coordination with utilities and private industry is required - and the nation will be stronger for it.

Now is the time for federal, state, and local governments to pass policies that reduce regulatory hurdles and create incentives to utilities and private industry to establish new infrastructure. Passage of bioenergy friendly amendments to the stagnating Energy and Farm Bills would be a very timely response demonstrating Congress' recognition of the long-term consequences of the problem while supporting green business and career opportunities for their constituencies.

Emerging technology companies can convert the woody biomass much more cleanly than their predecessors. This will create the economic means to address the gargantuan and urgent task of harvesting and replanting Katrina's catastrophic biomass legacy.

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Tim Hamilton said...

I'm impressed with the quote from Dr. Bonnicksen that describes leaving behind enough snags and logs for wildlife habitat.

On a related note, I wonder if this kind of plan will have any effects on the soil quality (esp. carbon and nitrogen levels)?

My educated guess is that it would as decaying logs are part of any natural forest ecosystem. However, given the threat of invasive species and the huge surge of greenhouse gases this temporary loss in soil quality would definitely be a good tradeoff all things considered.

When I get a chance I will look into this, but I was wondering if you are familiar with any studies that examine this question?


C. Scott Miller said...

I am not familiar with any studies about leaving biomass at the debris site. I know that key people advocating bioenergy - Tom Bonnicksen and Bill Holmberg of the BCC of ACORE - are intensely interested in the subject of harvesting techniques and soil quality. It is at the heart of making any new energy paradigm environmentally sustainable.

You might look up studies on biochar, agrichar, and terra preta while you are at it. They are different names for essentially the same thing - the practice of adding biomass char back into the soil to fertilize it.

See .