Fire and Smoke Can Be Good and Bad

Fire and Smoke Can Be Good and Bad

29 January 2010

published by

USA — Recent ecological research has shown that forest fire is an integral component to the function and biodiversity of many ecological communities, and that the organisms within those communities have adapted to withstand and even exploit it. A fire may destroy one ecological community but allow greater long term diversity. It is not just the fire but the smoke too. Smoke plays an intriguing role in promoting the germination of seeds of many species following a fire. Even the carbon dioxide from a fire has an impact on the overall ecosystem.

Fire behavior is different in every ecosystem and the organisms in those ecosystems have adapted accordingly. One sweeping generality is that ecosystems fire create a mosaic of different habitat patches, with sites ranging from just burned to untouched by fire for years, through a process known as succession. Succession is the progress of a site through continuous and directional phases of colonization by and extinction of species populations after a disturbance, such as fire.

After a fire, the first species to colonize are those whose seeds are already present or those whose seeds disperse to the burned area quickly. These are generally fast growing herbaceous plants that need lots of light and are poor competitors in crowded areas.

As an example in a recent study published in the Journal of Natural Products it was reported that a chemical compound in smoke from burning plants promotes seed germination. Such seeds, which remain in the undercover on forest and meadow floors after fires have been extinguished, are responsible for the surprisingly rapid regrowth of fire devastated landscapes.

In their research, the scientists report discovery of an inhibitor compound that may block the action of the stimulator, preventing germination of seeds. They suspect that the compounds may be part of a carefully crafted natural regulatory system for repopulating fire ravaged landscapes. Interaction of these and other compounds may ensure that seeds remain dormant until environmental conditions are best for germination. The inhibitor thus may delay germination of seeds until moisture and temperature are right, and then take a back seat to the germination promoter in smoke.

A recent study at Oregon State University indicates that some past approaches to calculating the impacts of forest fires have grossly overestimated the number of live trees that burn up and the amount of carbon dioxide released into the atmosphere as a result. A forest fire does not cause a complete destruction or release of carbon dioxide to the atmosphere as compared to the deliberate combustion of fossil fuels. So though a contributor to atmospheric carbon dioxide levels and potential global warming, forest fires are not a significant new contributor.

A forest fire is part of the overall ecology and is part of the overall balance despite earlier fears that forest fires were only destructive.

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