ASSESSING CARBON SINKS AND OTHER BIOGEOCHEMICAL CHANGES WITH PLANTATIONS: A GLOBAL SYNTHESIS
Carbon sequestration programs have gained considerable
attention as a mechanism to offset human-induced greenhouse
gas emissions and reduce atmospheric carbon dioxide concentrations.
The most prevalent type of carbon sequestration program
in use at present, and likely to be used in the near future,
is tree planting, especially afforestation (the creation
of plantations in areas that had not previously supported
trees such as grasslands and croplands) and reforestation
(the creation of plantations in areas that had previously
supported trees). Much attention has been paid to estimating
the net amount of carbon sequestered in vegetation and
soils over specific periods of time as a result of tree
planting, and to estimating the financial costs of tree
planting programs, but little consideration has been given
to the non-carbon biogeochemical changes that result from
these programs.
The plantations working group will:
•Evaluate the carbon and financial assumptions behind
plantation carbon sequestration programs, including
the importance
of rotation rates, a full accounting of carbon costs
(e.g., planting and site preparation), and how the
stored carbon
would be safeguarded. This activity will include evaluations
of both above- and belowground carbon storage.
•Examine the scale of the process needed to offset
a substantial portion of global fossil fuel emissions
(more specifically,
about 25% of current annual CO2 emissions from developed
countries each year for 50 years, or about 50 Pg C
total).
•Determine and summarize the evidence for other biogeochemical
changes that will likely occur. Some of the factors
to be evaluated include soil acidification, changes
in water
fluxes and water-table dynamics, nutrient losses and
redistribution, changes in soil fauna and biodiversity,
volatile organic
carbon emissions, and erosion.
The group will examine four regions (the United States,
South America, Australia, and China), with a goal to recommend
optimal sequestration measures based on a full consideration
of both biogeochemical and economic factors.
The group is composed of individuals from a number of
disciplines (forest ecology, biology, biogeochemistry,
hydrology, geography, and economics) and a number of institutions:
Robert B. Jackson, William H. Schlesinger and Kathleen
Farley (Duke University)
Troy Baisden (Landcare Research, New Zealand)
Damian Barrett (CSIRO Plant Industry, Australia)
Josep Canadell (Global Carbon Project, Australia)
Alex Guenther (National Center for Atmospheric Research)
Marcel Hoosbeek (Wageningen University, the Netherlands)
Esteban Jobbágy (University of Buenos Aires,
Argentina)
Steve Pacala (Princeton University)
