Management strategies in agriculture and forestry for mitigation of greenhouse gas emissions and adaptation to climate variability and climate change : report of the CAgM-XII Working Group on the Impact of Management Strategies in Agriculture and Forestry to Mitigate Greenhouse Gas Emissions and to Adapt to Climate Variability and Climate Change; [at the] twelfth session [of CAgM) held in Accra, Ghana, in February [18-26], 1999.