CO2: Trees Taketh and Trees Giveth Away

Canada has vast forests and Canadian political leaders are counting on the trees of these forests to take up enough carbon dioxide to offset the carbon dioxide emitted by the burning of coal, oil, and gas in Canada when it comes to meeting their Kyoto Protocol targets. However, an article in the Ottawa Citizen points out that scientists have found that trees do not appear to take up carbon dioxide over time. Rather, their measurements in a black spruce forest in Canada show that at certain times trees do take in carbon dioxide but at other times tree give off carbon dioxide with the net effect being about zero change in carbon dioxide. The issue gets more complicated when it comes to planting new forests which can store carbon dioxide and the burning of forests which releases carbon dioxide and whether it is the short-term effects or the long-term effects on carbon dioxide levels that are being considered. It seems unlikely that there will be any consensus soon about the role of trees in combating global warming making the whole issue of offsetting carbon emissions with trees that much more confusing.