Wise management of our soils is a critical requirement for New Zealand to be fully sustainable. In order to farm sustainably we need to manage our hills and slopes free of erosion and tree planting is ideal for that. Those trees can also be a crop if planted appropriately and with appropriate species. Managed erosion control requires the trees to be managed and harvested at appropriate times. The residues from that tree harvest can be used as a source of biomass to produce energy.
Similarly we can sustainably manage other soils by recycling the residues from crops or animal effluent as a biofertiliser. The residues can be processed in an anaerobic digestion facility to produce high grade fertiliser.