Return
to the Reasons To Believe Home PageNo one needs a scientist to prove that life on Earth would be severely impacted, m both in quantity and in diversity, if wild fires were more frequent and widespread. scientists have been helpful, however, in identifying the primary factors that determine fires' prevalence: 1) the quantity of atmospheric oxygen, and 2) the electric discharge rate.1 If these were greater, we wouldn't be here to learn about them.
New soil science studies reveal we'd be in the same kind of trouble without enough forest and grass fires.2 Farmers have long recognized the benefits of burning. For centuries they have been burning their fields periodically (if nature doesn't) to increase crop yields. The new findings simply enhance our understanding of why and how burning works and how much burning is ideal for the planet.
First, fires get rid of certain growth inhibitors. Anyone walking through an old forest notices the accumulation of dead vegetation on the forest floor. Burning off this organic litter enhances germination as seeds and seedlings gain greater access to the mineral soil beneath. Old forests also accumulate certain plant- and microbe-suppressing agents. Burning stimulates essential microbial activities, such as nitrification of the soil. A byproduct of forest and grass fires is charcoal, which benefits the soil by absorbing tannins and other chemical plant- and microbe-inhibiting agents that have settled there. During and after a fire, charcoal is easily broken down into fine dust and ash, which is easily transportable by wind and water to land adjoining the burn area, especially into valleys. This dust and ash, relatively chemically inert, greatly enhance the soil's water retention capacity. Dust and ash can transform even sandy soil into a clay-like material.3 This transformation process is a significant source for the development of new wetlands. It could also play a role in the development of peat bogs and, thus, coal formation. Like charcoal filters used in water purification systems, the benefits of soil charcoal dwindle with time. Studies of Swedish forests indicate that the benefits of the charcoal steadily decline after a fire, down to one-eighth of its original effectiveness in100 years. After 200 years, no measurable benefit remains. Studies in American forests demonstrate that fires every 20 years, for example, do much less damage than fires every 150 years. These findings have led researchers to estimate that Earth's biomass and biodiversity are maximized if forests and grasslands bum every 20 to 100 years-precisely the natural rate ecologists measure for much of the planet.
How much fine tuning of oxygen abundance, atmospheric electric discharge rates, wind, rainfall, and plant chemistry is necessary to keep the rate of natural fires within the ideal range? Numbers are difficult to assign, but we know it's at least a few orders of magnitude more than we knew before soil scientists began their research. We can say that scientific investigation has, once again, augmented the case for God's meticulous and comprehensive design of Earth, a design that seems to have humans' needs in focus.
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