Forest scientists have come to a surprising conclusion regarding old growth forests and their majestic, mature trees: They’re not just relaxing in their arboreal old age, but are still actively taking in carbon dioxide from the atmosphere. The new study suggests that protecting old growth forests may be just as important as planting new trees in efforts to reduce carbon dioxide levels and fight global warming.
Previously, researchers believed that only young, fast-growing trees absorbed enough carbon dioxide to be considered significant “carbon sinks.” Old, crowded forests don’t allow for much new growth: The only new growth occurred in the small spaces that opened up when large old trees died and decomposed, releasing their accumulated carbon. The forests at large were therefore considered to be carbon neutral, and accounted as such in climate models [Nature News]. But the new study shows that the slow but continuous growth of old trees means that they continue to suck up more carbon than they release.
For the study, published in the journal Nature [subscription required], researchers examined over 500 studies of forests around the world. They calculated that primary forests in Canada, Russia and Alaska alone absorb about 1.3 gigatonnes of carbon per year, about ten percent of the net global carbon exchange between the ecosystem and the atmosphere. These forests need to be protected not just because they help to absorb carbon dioxide, but also because destroying them could release huge stores of greenhouse gases. “Old-growth forests accumulate carbon for centuries and contain large quantities of it,” [lead researcher Sebastiaan] Luyssaert said. If these pools of CO2 “are disturbed, much of this CO2 will move back into the atmosphere,” he added [AFP].
The new findings suggest that old forests should be included in any policies intended to mitigate global warming. Study co-author Beverly Law says that the findings argue for including credits for preserving old growth forests in the Kyoto Protocol and cap-and-trade schemes for controlling greenhouse gas emissions blamed for global warming [AP].
Image: flickr/paulhami
September 11th, 2008 at 5:10 pm
hi dr. holloway hire is the work
December 16th, 2008 at 1:30 pm
So much to do, so little time, Stand and make your mark.
“We will have to repent in this generation not merely for the hateful words and actions of the bad people, but for the appalling silence of the good people.”
Martin Luther King, Jr.
February 2nd, 2009 at 6:44 pm
This sounds rosy, but it is a typical over simplified, agenda driven article.
First, the balance between CO2 uptake and release by old growth trees can vary considerably by species. For example, Coast Redwood, (as shown in the photo) will not decay nearly as rapidly as a species such as White fir, which can easily be a net emitter in an old growth stand.
Second, a young well stocked stand of healthy, fast growing trees unquestionably absorbs more CO2 from the atmosphere than any “old growth” stand.
Third, the article mentions “stored” carbon and the possible “destruction” of it with subsequent release. Yes, that is exactly what could happen if the forest is left alone, not managed, and has a large scale stand replacing fire event. Poof, there goes your CO2 into the atmosphere. If we manage the forest, we can reduce the possibility of a catastrophic stand replacing fire, and in doing so, store carbon in our walls and floors in the form of lumber and other wood products. Seems like a win-win situation to me.
In conclusion, we all like big trees, but we shouldn’t allow our feelings to get in the way of facts. Preserving old growth with a “hands off” approach may sound compelling for many reasons, but it is certainly not the safest and most efficient way to permanently store carbon. In reality, some old growth forests actually create a lurking danger!
August 31st, 2009 at 3:05 pm
This one reminds me of a Dan Akroyd character on Saturday Night Live. He played this business owner that made toys for kids like bag of glass. He would take toys they had that Jane Curtin would say was safe and would shove it down his mouth a pretend to choke, or slip on it and pretend to fall down to show how dangerous the other toys were. Looks the same to me as this premise.
April 4th, 2011 at 11:54 pm
I was just chatting to my little sister about this yesterday. I also seen something on that over at the ulta website. Isnt it humorous how these things show up in bunches. to be frank, it is kind of intimidating.