TREES CAN DO PART, THE REST IS UP TO PEOPLE

Trees are a valuable ally, but we ask too much of them at our own peril.

Global Warming: Carbon Dioxide ‘Tree Banking’ May Help, Provided Trees Have Optimal Water, Nutrient Levels
August 7, 2007 (Duke University via Science Daily)

WHO
Ram Oren, project director, Free Air Carbon Enrichment (FACE) experiment and professor of ecology, Duke University's Nicholas School of the Environment and Earth Sciences; Heather McCarthy, fellow, UC Irvine, former graduate student with FACE and report presenter; Other FACE researchers: Kurt Johnsen, U.S. Department of Agriculture's Forest Service; Adrien Finzi, Boston University; Seth Pritchard, University of Charleston; Robert Jackson and Charles Cook, Duke; Kathleen Treseder, University of California, Irvine.

WHAT
The results of the FACE experiment demonstrate that trees continue to grow more tissue in the presence of higher saturations of CO2 but only if they get optimal water and nutrients.

This aerial view shows the research forests with the rings of CO2-saturating towers amid them. (click to enlarge)

WHEN
FACE was conducted 10 years before these conclusions were drawn. Report made August 7.

WHERE
Report to the Ecological Society of America (ESA).

WHY
- 4 North Carolina loblolly pine tree stands were daily administered CO2 at 1.5 times present conditions via computer-controlled valves mounted on a ring of towers. 4 matched plots received no CO2. Carbon accumulations were studied. CO2 drenched stands on average had 20% greater biomass. Stands with optimal water and nutrients added as much as 40%, while those with sub-optimal conditions gained 5-10%.
- Self-thinning was unchanged—survival of the fittest still applied. CO2 was also stored in unchanged proportions throughout the tree system (wood, leaves, roots and underlying soil).
- Funding by US Department of Energy.

A schematic demonstrating the central role of trees in the carbon (life) cycle. (click to enlarge)

QUOTES
- Oren: "If water availability decreases to plants at the same time that carbon dioxide increases, then we might not have a net gain in carbon sequestration…In order to actually have an effect on the atmospheric concentration of CO2, the results suggest a future need to fertilize vast areas…And the impact on water quality of fertilizing large areas will be intolerable to society. Water is already a scarce resource."
- McCarthy: "Carbon that's in foliage is going to last a lot shorter time than carbon in the wood, because leaves quickly decay…So elevated CO2 could significantly increase the production of foliage but this would lead to only a very small increase in ecosystem carbon storage."