A Letter from David L. Smith
A Response from the Publisher

You write (Commentary, July 14, 1998):

However, to understand the plan's environmental consequences and its long-term impact on the economy of British Columbia, a number of questions must be answered.

Well, and good. However, I noticed a number of leading questions like:

How much carbon will be released to the atmosphere following selective logging as a result of the decay of logging slash, stumps and roots of harvested trees, and the organic matter of soil warmed by exposure to the sun?

You neglected to note the amount of carbon absorbed from the atmosphere by the rapidly growing plants nourished by the decaying organic matter and warmed by exposure to the sun. If the unscientific, capitalistic lumber company can be faulted for not being detailed enough, why shouldn't the impartial, scientific authors that had a hand writing this commentary?

What is wrong with:

What is the balance of carbon cycled to and from the atmosphere over a period of two hundred years in the logged area as opposed to the unlogged areas?

See? Easy. A simple question that is interesting to either side of the subject, but without personal bias from the onset.

David L. Smith
davids@invtools.com

Reply to David L. Smith

Our question, which David Smith cites, is more relevant to the point at issue (see naturalSCIENCE Commentary) than the alternative he suggests.

At issue is the impact of old-growth logging on atmospheric carbon dioxide concentration during the next several hundred years, and the consequences of that impact for global climate. In attempting to deal with this, David Smith confuses two questions: the amount of carbon stored in trees and forest soils, and the flux of carbon between forests and the atmosphere.

There is no question that young forests absorb carbon dioxide from the atmosphere more rapidly than old forests. But there is also no question that, in general, old-growth forests, including their soils, contain vastly more carbon than young second-growth forests.

Altogether, the carbon bound in forests and forest soils is equal to twice that presently in the atmosphere. It is inevitable, therefore, that rapid conversion of large tracts of old-growth forests to young second-growth stands will significantly increase atmospheric carbon dioxide concentration. The increase occurs during the years immediately after logging as a result of the decay or combustion of stumps and logging slash and the hastened decomposition of organic matter in soil warmed by exposure to the sun. In addition, there will be a more or less rapid return of carbon to the atmosphere from extracted timber (e.g., caused by the combustion of fuel wood, or the decay of other wood products, few of which last as long as old-growth forest stands). Destruction of old-growth forests is thus among the most significant potential causes of anthropogenic global warming.

David Smith may be correct to assume that if one logs an old-growth forest and waits for it to regrow over a period of several hundred years, one will have back the forest that one started with. During the interim, however, if the extent of logging is sufficient, the increased atmospheric carbon dioxide concentration due to the loss of old carbon-rich forests may have a catastrophic climate impact.

The Publisher

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