By Pat Tigges
If we must include environmental science in a public school curriculum that is already more fluff than substance, at least we should demand good science. Scores of children have told me we must save the rainforests because they are the lungs of the planet.
There are many good and scientifically sound reasons for saving rainforests, but oxygen supply is not one of them. In spite of their lush vegetation, rainforests developed on very poor soils and most of their nutrients are located in the plants themselves or in the decomposing layer on top of the soil. Only 8% is located in the soil itself.
All the systems of plant nutrition in the rainforest are engineered to guarantee very little net loss. In other words, very little uptake from the nutrient sources. They conserve nutrients and cycle them around and around. They evolved as closed nutrient cycles.
Closed nutrient cycles are mature forests and mature forests operate at their climax. In other words they don’t produce more than they use. They have been recycling the same amount of carbon for centuries. The oxygen they produce is totally consumed by the vegetation breathing. The balance between oxygen production and consumption is zero! And in fact, mature (old growth) non-tropical forests actually consume more than they produce.
The lungs of the planet are young, actively growing trees: new forests, replanted forests, plantation or farmed forests.
Pat Tigges is president of the Pacific Northwest Aerial Applicators’ Education Foundation (PNWAAEF)
Reprint permission given by AgAir Update, P.O. Box 850, Perry, GA 31069 - an international agricultural aviation publication.
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