By PAUL HETZLER
Cornell Cooperative Extension of St. Lawrence County
Using wood chips for fuel is nothing new, but until recently those chips have come almost exclusively from hardwood whole-tree chipping operations.
Short-rotation willow (also called shrub willow) is a new chip source that uses marginal farmland to produce a harvest of wood chips every three years over a crop lifetime of 20-25 years.
In December 2012, Cornell held a workshop on short-rotation willow at their research station in Geneva, where they have a test plot of shrub willow that’s already producing chips to heat some of the research buildings. Presenters outlined several advantages to growing willow, the first being that marginal fields can be used. Once established, willow can do well in many soil conditions, but it thrives in wet sites that won’t support other crops.
Another plus is that the wood chips can be harvested with a conventional self-propelled silage chopper. This eliminates the expense of buying a dedicated machine, and because harvesting is done in the winter, it extends into another season the use of the chopper. There are, of course, challenges: The initial planting cost is high and there’s no cash flow for three years. Harvesting can be delayed if the ground is too wet or doesn’t freeze. Also, the chopper has to use a special header, as well as forestry-grade tires, which are much more puncture resistant.
Markets are another consideration, although there are many potential users, from small businesses to large co-gen plants and institutions. Colgate University in Hamilton, N.Y. heats about two million square feet of building space using mostly wood chips—22,000 tons a year to be exact. Incidentally, all those chips come from within a 60-mile radius of Colgate.
While the initial cost of converting to wood chips is considerable, the rewards are, too. The East Lycoming School District in Pennsylvania switched to wood chips, having scored a competitive grant to pay for the boiler. But that’s not even their best news: Their energy cost using wood chips is $4.63 per million BTUs, compared to about $10.00/ mmBTU for natural gas and $29.00/ mmBTU for oil. When you have a sustainable energy source that’s half the cost of natural gas, you can’t afford to ignore it!
In the coming years, farming short-rotation willow will become an increasingly viable opportunity for North Country farmers.
Paul Hetzler is a forester and a horticulture and natural resources educator for Cornell Cooperative Extension of St. Lawrence County.