For Roger and Marie Haynes of Neepawa, Manitoba the search for a way to heat their farm and greenhouse so they could grow food year-round led them to a unique greenhouse covering and willow plantings as a renewable crop. Willow can produce a large quantity of biomass in a short period of time, has low input requirements and a positive environmental impact. Willow provides biomass for generating heat and electricity, sequesters carbon and has bioremediation potential.
The Haynes started in 2006 by contacting people locally, nationally and internationally for advice. “We learned so many things and found out it was not as straight forward as we thought, but it could be,” explains Roger. “For this project, we wanted to determine what species would grow in Manitoba, the yield produced by different varieties in a wood chip form, the requirements for successful production and to develop necessary machinery.”
There were many lessons learned from the project, starting with sourcing the right willow clones from established nurseries, and ensuring proper transportation and storage of the cuttings at correct temperatures. A well-prepared seedbed was required for planting the eight-inch cuttings, which are pushed completely into the ground. “Currently in Canada, plantings are mostly done by hand as typical tree planters don’t work very well,” says Roger. “Planting a willow cutting is really like pushing a pencil into the soil. Generally, 5000 to 6000 cuttings are planted per acre. A good person can probably plant between 3500 and 4000 cuttings a day properly by hand.”
In Europe and other places, growers often use a step planter to mechanically plant willows at a rate of 15,000 plants per hour. “These step planters take willow whips, pushing them into the ground and cutting them off at the right length,” explains Marie. “In Canada, we currently do not have enough stock to have whips to plant, we are still relying on smaller cuttings so the step planter isn’t ideal. Roger is working on building a cutting planter for us.”
Weed control is another big challenge for production, and until 2011 there were no herbicides registered for control in willow plantations. “The Poplar Council of Canada is starting to address this issue and is working towards some solutions for Canadian producers,” says Roger. “Once we managed to control the weeds, the willow growth was phenomenal, growing from a cutting to 8 feet high in 16 weeks.”
Based on advice and experience from others around the world, the Haynes coppice or cut the willow plantings close to the ground after 12 months.  “After coppicing, we get three shoots from every shoot, which quickly multiplies the plantings and then we harvest either after three or four years,” say Roger. Marie adds that willows should be harvested after the plants have gone dormant and the energy has returned to the roots so the plants will regenerate. “Harvesting the trees before they go dormant can shorten the life of the crop,” she says. “A well established perennial willow plantation should produce for 20 or 30 years.”
In most other parts of the world, a standard farm forage harvester with an adapted header is used for harvest to cut and chip the willow in one step. “We did our first harvest by hand because we didn’t have the special header, cutting down the trees with chainsaws and leaving them to dry in piles over the winter,” says Marie. “After much frustration, we tried driving the forage harvester directly in the piles, which worked very well and produced some beautiful chips that should burn well.” The yields from two varieties provided by the Agroforestry Development Centre in Indian Head, Saskatchewan produced satisfactory yields for the first harvest, with Salix Viminalis averaging 5 lbs of chopped material per plant or 11 tones/acre, while Salix Acute averaged 3 lbs of chopped material per plant or 6 tones/acre.
Willow Biomass Opportunities and Challenges
Markets for biomass are developing, and in Europe some estimates suggest that 50% of the current 100 million tonnes of coal used per year in power generating stations will be replaced with wood biomass. “Canada is one of the markets considered as a potential supplier,” explains Roger. “One advantage is our climate and fall frosts which allows machinery harvest in late fall on marginal lands. Another advantage in Manitoba is the port of Churchill, which is about 300 miles closer to Europe by sea than New York, so shipping costs should be less. I believe we can supply part of that market, which would provide an alternative crop option for farmers on marginal lands.”
The Haynes recognize the challenges to successful production and continue to talk to other producers and researchers around the world. Adapting seeding and harvesting equipment, access to suitable clones, weed control products and proper biomass burners such as new ones being developed in Europe that can burn at 50% moisture are still some of the challenges. “There seems to be small pockets of producers across Canada, but we really need to be talking to one another,” says Roger. “We are happy to talk to people and help out in any way we can and to avoid some of the mistakes we made early on. We are also the Canadian supplier for a unique greenhouse covering product from Europe, which combined with willow biomass heat can produce food year-round even in northern climates.”