Trees Won’t Fix Global Warming

trees.jpgWe’ve had doubts. Research says we should:

Scientists at Duke University bathed plots of North Carolina pine trees in extra carbon dioxide every day for 10 years and found that while the trees grew more tissue, only the trees that received the most water and nutrients stored enough carbon dioxide to offset the effects of global warming.

Bottom line: “if a drought takes hold, trees won’t be able to do much in the way of carbon storage.”

One researcher noted, “If water availability decreases at the same time that carbon dioxide increases, then we might not have a net gain in carbon sequestration.” Well, climate change is projected to decrease water availability in many parts of the world, including the American West.

Other interesting findings:

“In order to actually have an effect on the atmospheric concentration of CO2, the results suggest a future need to fertilize vast areas,” Oren said. “And the impact on water quality of fertilizing large areas will be intolerable to society. Water is already a scarce resource.”The results of the study, presented yesterday at a national meeting of the Ecological Society of America, also noted that only a few parts of a tree will store carbon for long periods of time.

“Carbon that’s in foliage is going to last a lot shorter time than carbon in the wood, because leaves decay quickly,” said Duke graduate student and project member Heather McCarthy. “So elevated CO2 could significantly increase the production of foliage, but this would lead to only a very small increase in ecosystem carbon storage.”

Trees should not be sold as carbon offests.


8 Responses to Trees Won’t Fix Global Warming

  1. Paul K says:

    Tree planting may be poor for carbon offset, but has other environmental and aesthetic benefits especially in urban and suburban settings.
    Would you agree that the only true carbon offsets are those that provide wind, solar or hydro power production?

  2. Cliff says:

    This is not good. Our contingency plans (or hopes) are getting pared down a bit, though like many, I ‘ve had my doubts. In Phoenix, they have to use precious water to keep trees growing in the city and on private grounds. That doesn’t appear to be sustainable today.

    I agree, trees serve other essential roles (e.g. slowing sand erosion) besides absorbing carbon. It’s a question of triage at this point – where do we put our limited resources to make the biggest difference. I think Joe and others have made the case that ending emissions from today’s coal plants is the smartest first step. But the political inertia in our country is enormous.

  3. Simon D says:

    The results have been misinterpreted to some degree (i’m just an observer, i’m not involved in any way). The research done at Duke’s FACE (Free-Air Carbon Enrichment) site is important for understanding how trees will respond to higher levels of atmospheric CO2. People had assumed that more CO2 = more tree growth, but increasingly, as this study shows, scientists are finding that nutrients and water can place a limit on this CO2 “fertilization” effect. An important finding.

    That’s different than saying planting trees won’t take up ANY carbon. It would — all that wood is made of carbon, where else would it come from? (think about the forest as a reservoir of carbon, though very short-term related to aptly-named “fossil” fuels buried deep in the earth). This research is showing that there won’t be an extra growth bump once expected because there’s more CO2 levels in the air.

  4. Dano says:

    The FACE studies for some time have been noting that forests, being nitrogen-limited, will have a hard time utilizing added CO2. FACE have also discussed the increased O3 in the atmosphere and the deleterious (cancelling) effects on CO2 absorption. FACE have also hinted at less atmospheric water vapor due to changed water relations in trees (closing of stomata in response to elevated CO2. And so on…



  5. TreeBanker says:

    I haven’t read the report yet but I have noticed that it has been referred to on many blogs today.

    It seems to me that either the report is being quoted out of context or it was referring to growing trees in a specific region.

    Everytime I read these comments all I hear Is: “Since it doesn’t rain much in my back yard and the soil in this area isn’t very good for growing trees, trees aren’t good for sequestering carbon.”

    What about growing trees in the tropics where they get 160″ of rain per year and the soil is so fertile that no fertilizer is required?

    If teak trees are measurably sequestering 26 tons of carbon per year per hectare, how can anyone say that trees don’t absorb carbon.

    Like Simon said in a previous post, trees are made of carbon.

    Dan T…the TreeBanker

  6. Grandmacharlottes says:

    Even if planting more trees will not help stop global warming, continuing to cut so many of them down has to have damaging effects on our atmosphere.

    All plants produce oxygen and intake carbon monoxide, especially large trees, yet we are clearcutting our worlds forests at an alarming rate. The percentage of oldgrowth forests that remain everywhere is miniscule to what it once was.

    I think the more trees we leave where they are and the more trees we plant now worlwide the better off our planet will be, now and in the future.

    Old hippie treehugger : }

  7. jawbone says:

    What Treebanker and Simon said.

    Also, some studies show that young, growing trees take in more carbon than older trees, which are, by being, “sequestering” carbon still. But, when forests are cut down on massive scales in South America, the actual weather changes without the ouput from the tree canopy.

    All in all, more trees are good–not a silver bullet, but contribute in more than one way.

    Joyce Kilmer’s poem begins with its two most famous lines: “I think that I shall never see / A poem lovely as a tree.” An old, 70-foot-high white oak tree that used to be located at the Rutgers Agricultural School, later the location of the Labor Education Center on Cook campus, was Kilmer’s inspiration to this world-renowned poem.

    Since then, this famous 300-year-old tree had to be cut down in 1963 because it was dying. Although it was hewed four decades ago, its remnants still exist today, and most of the pieces of the tree are still owned by Cook College. (Poem at link below.)