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Foresters in general and farm foresters in particular have a much more valuable resource than just the logs or lumber.

Forest harvest contractors too could make more money by regarding the total tree, especially what is now left to rot, as a multi-product supply.

"We're getting to a stage now where greater volumes of biomass is required for bioenergy activities," says Bioenergy Association of NZ Executive Director Brian Cox.

"Using wood waste onsite, as in a sawmill has been economic for a decade. It's now becoming economic to buy in such products from forest harvest residues and purpose grown short rotation crops."

Cox gives the examples of wood chips and reformed wood pellets being used directly as a heat source, replacing coal in furnaces. The same chips or pellets can also be burned in a gasifier (retrofitted to an existing gas boiler) and used to replace natural gas .

However, this requires an understanding the science of combustion of biomass, under different pressures, temperatures and amounts of air so that it can be utilised for its solid, liquid and gas characteristics - and sometimes a combination of them.

By using lignocellulose from trees and short rotation crops such as willows to make bioethanol or biodiesel, and extract the other 'good bits' for use in new biomaterials, landowners have new potential income streams. Cox says it will take 10-15 years to develop commercial plant to make bioethanol or biodiesel from such sources, but that people should be planning for it now. Internationally pilot plants are being built and this is the last stage before full commercial investment.

He is a strong advocate that energy crops will be complementary to traditional land uses. He gives an example of kiwifruit growers, whose 10ha property may only have 6ha of crop. The other 4ha could be planted in Miscanthus (a type of woody grass), and cropped annually as a feedstock for ethanol production.

Cereal growers in South Canterbury are doing a similar thing now with regard to growing rapeseed for the production of oils for making biodiesel. The rapeseed is a fourth break crop so their soil fertility is improving along with their financial viability.

Cox says while one property's production may not be enough for a commercial ethanol plant, if say 10 orchardists got together, it would form the basis for contract production from someone willing to install it. The same feedstock could, dried and baled, be an alternative for coal in a boiler .

On more pastoral-type properties, pine trees are probably more suitable for land steeper than 15 degrees, but other woody fibre short rotation crops can be considered on flatter land.

"On many farms you can have an opportunity for a mix and match in terms of production of bioenergy feedstocks, the nature of the land, the market and timing," says Cox. "Farmers might be better off growing other species such as eucalyptus for example, which can have better value because of its other byproducts."

Cox says that as a nation we need to really start thinking about the potential for bioenergy crops as they can be a stimulus for the economic growth that the government is seeking.

His association has produced an 18 page document, 'New Zealand Bioenergy Strategy', which suggests a three phase approach to developing business opportunities that in 30 years could produce 25% of the country's energy needs, including 30% of the country's transport fuels.

The Ministry of Economic development Energy Outlook analysis supports the Association's (quite conservative) numbers and assumptions and that the strategy supports a realistic scenario 10-15 years out.

"We want to get the information out there, and gives the market view that this is what we think could happen," Cox says.

"Entrepreneurs and land owners need to see that there are opportunities here."

Land and forest owners should look beyond the log

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