Growing trees for carbon trading will not interfere with food production, establishment costs will limit carbon forestry's expansion rate, CSIRO researchers find
DUNEDIN, New Zealand
July 8, 2011
– Agroforestry may become a much more important farm enterprise under the Carbon Farming Initiative, but not to the extent that trees will interfere with food production. New assessments by CSIRO show that establishment costs will be a significant factor in moderating the spread of "carbon forestry", unless the returns on carbon offsets rise above AU$40 a tonne.
Even so, CSIRO scientist Michael Battaglia says, there are physical limits to how quickly forests can be planted, and there are social barriers against blanket changes to land use. "A lot of people are going to prefer to farm their land, rather than plant trees, and they are also going to have preferences based on risk," Dr Battaglia said. "Not everyone will want to reduce their land-use options by planting trees."
CSIRO researcher Phil Polglase and colleagues in AgResearch, New Zealand, and the SA Department of Environment and Natural Resources have looked at the opportunities and limitations of carbon forestry.
"The availability of seed, tube-stock, machinery and labour all limit the rate of establishment, along with the area of suitable land that becomes available over time," the researchers said. "It also takes time to build up a suitable infrastructure to support plantation establishment."
At the height of MIS expansion, the largest area of plantation established in any one year was about 140,000 ha in 2000. Averaged across five years at the peak of the expansion period, from 1998-2002, about 86,000 ha of plantations were established. That makes it unlikely that carbon forests will have a significant spread by 2020, but by 2050, assuming that infrastructure is in place and a strong carbon price, there could be scope for 10-20 million hectares of plantings on marginal land.
That could produce about 50-100 million tonnes a year of carbon dioxide emissions reduction, about 20 per cent of current emissions, the researchers estimated. But the researchers acknowledge a swathe of unknown factors, including future carbon pricing and the possibility that forestry over more than 10 per cent of a land holding might attract a charge for water interception.