Biochar becoming a hot topic

When it comes to forests and climate change, the big New Hampshire angle is that we should create more energy by burning trees: making more heat from wood pellets or electricity from biomass power plants.

But maybe we should also be thinking about making "biochar," a version of charcoal.

That, anyway, is the point of view that will be taken at a Saturday conference in Temple, where biochar will be the topic of discussion as a way to fight climate change and help our forests, since it can be used as an energy source, as a fertilizer and as a way to trap and store carbon from the air.

Basically, biochar is wood or other organic material that has been burned in ticular ways, absorbing large amounts of carbon in the process. The temperature, timing and lack of oxygen are controlled in such a way as to cause pyrolysis, a form of combustion in which organic compounds break up and are bound into the resulting clumps of biochar.

Biochar, which looks like a cross between charcoal briquettes and cooled lava, is a hot topic. I had never heard of it until this spring; now it's all over "green" publications and Web sites, and it had its first major academic/industry conference in Boulder, Colo., earlier this year. It is the subject of much research by both agriculture and energy scientists.

For example, a researcher at the University of Georgia told the United Nations that the U.S. could offset 11 percent of its emissions each year by creating 650 million metric tons of biochar annually and burying it.

Agriculture folks are excited because biochar is a great fertilizer. This is no surprise to those of us with wood stoves, whose ashes are valuable components of compost.

I admit to being a little confused about all this.

Burning wood in forest fires is cited as a source of greenhouse gas, so how can burning wood to create biochar reduce greenhouse gas? And I don't understand how something can sequester carbon and also be a fertilizer, which requires the release of material into the soil.

But then again, if it was screamingly obvious, we wouldn't need conferences to explain it.

Which brings us to Saturday's event, sponsored by the Harris Center for Conservation Education in Hancock.

It will feature David Yarrow, a biochar advocate who has been spreading the word throughout the Northeast; and a Cape Cod blacksmith who is making retorts – vessels in which things can be heated – for creating biochar.

The conference will also feature a bunch of foresters and forestry officials, because of biochar's possibility both as a market for wood products and a source of large-scale fertilizer for woodlands.

Finally, there will be a research director from a Canadian company called Alterna Energy, which makes biochar and similar products from wood and municipal waste.