The Ministry of Agriculture and Forestry says owners of older forests who are entitled to free carbon credits under the Emissions Trading Scheme will need to make a decision about that over the next year.
MAF is holding a series of regional seminars which started this week to help more than 5000 owners of forest land planted before 1990 decide whether they want to apply for a one-off allocation of carbon credits or an exemption from deforestation liabilities.
Those forests cover more than 1 million hectares and make up more than half of New Zealand's exotic plantations.
MAF's operations manager Rob Miller says they can't earn carbon credits as their trees grow, but under the international Kyoto protocol they still face penalties if any of their trees are cut down.
Mr Miller says pre-1990 forest owners who opt for a deforestation exemption need to apply before the end of September next year, and those wanting an allocation of carbon credits have until end of November next year.
The carbon credit seminars will continue throughout August.