In Sweden, fast growing tree species such as willows have been cultivated for many years as snort rotation energy crops. 

A demonstration of the techniques and equipment for "energy farming" was one of the highlights of the opening day at Elmia Wood.

The Jaguar chopper by CLAAS is the business end of this process.  Watch it on video

A combined feller and processor, the Jaguar is used to harvest approximately five-year-old trees (maximum trunk circumference of 7 to 8 cm) by mowing them down and chipping them in one continuous operation. The trees are planted in double rows with 75 cm between them and a minimum of 150 cm between the double rows. 

Chips are blown into a "field shuttle" trailer system which can attached directly behind the chopper or pulled by a tractor alongside. 

The Jaguar chopper features the company's HS2 header with two saw disc blades designed to provide an even cut and leave a smooth surface on the stumps. The height of the header is adjustable to cut the stems as close to the ground as possible. According to CLAAS, the chopper's production capacity for crops with good mass growth is up to 70 tonnes per hectare of fresh biomass and a work rate of one hectare per hour. 

When not in use for tree harvesting, the Jaguar can be put to work for harvesting grasses or corn with a few modifications to the machine, mainly the cutting mechanism. 

A tractor-driven unit for cutting and planting willow shoots is also part of the system. 

Tree species that have been tested for short rotation energy crops are willows, which work well but need a good supply of water; poplars, which require less water; and the locust tree, which needs very little water and can take its nitrogen from the atmosphere. These species grow very deep root systems in their first year which allows them to regrow quickly after cutting and continue to produce for about 20 years.

Chips from short rotation crops have been found best for use as direct fuel for combustion or power plants and not as suitable for pellet manufacturing because of their high bark content which results in a higher ash content. 

Short rotation energy wood cropping takes planning and an initial investment of capital and time for the first planting to grow, but it is can be part of the solution for reliable and renewable fuel for the future.