When a two-ton tree burns to the ground, as in a forest fire, it emits into the atmosphere roughly three tons of carbon dioxide.

This is comparable to the CO2 emissions from a car consuming 1,400 litres of gasoline — more than most cars use in a year.

This is an unfortunate fact for us to have to face because, in this province, there are many more trees burning in the forests than there are cars on the roads.

When you add the effect of the pine-beetle infestation to net greenhouse-gas production it makes car emissions secondary, compared to nature’s events in our forests.

As with all discussions of climate change, it is basically a numbers game. So, to outline the basis of the approximate calculation here, it should be noted that trees are composed mainly of cellulose, which is about 40-per-cent carbon atoms by weight, and that gasoline is a hydrocarbon, which is about 85-per-cent carbon by weight.

All C-atoms, when combusted, finish up as CO2. Thus, two tons of wood result in about three tons of CO2 being emitted into the atmosphere. Likewise, 1,400 litres (or 0.95 tons) of gasoline results in three tons of CO2 being emitted. This 1,400 litres of gasoline corresponds to a lot of driving each year, even in an SUV.

In effect, there is too much hype about the car and not enough about controlling forest fires and pine beetles. The pine beetle poses a greenhouse-gas threat by killing trees. These, when no longer consuming CO2, become an extreme fire hazard and give off methane as they decay. We need more balance in the discussion of climate change.

David Walker

University of B.C. emeritus professor of chemistry, Vancouver

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