The Forest Owners Association says the only way New Zealand can meet its international obligations to reduce carbon emissions by 30 percent in the next ten years is to plant 500-thousand hectares of trees.
Land is needed for planting and a number of sheep and beef farms have been sold for forestry.
The lobby group 50 Shades of Green says it wants the sale of productive farmland to stop until there's been an assessment of the social, economic and environmental impact of the Government's Billion Trees programme.
Fifty Shades of Green says blanket planting will destroy rural communities and will reduce the amount of land available for food production.