Key barriers and issues to the extensive deployment of short-rotation plantation and agroforestry energy systems in Canada

Description

Dedicated short-rotation woody crop (SRWC) systems of concentrated willow or hybrid poplar are also known as short-rotation intensive culture (SRIC), short-rotation coppices, and concentrated biomass for energy plantations. These intensively managed area-based systems are characterized by very high planting density (approximately 15,000–20,000 cuttings/ha) and very short harvesting cycles of 3 to 4 years. Various clones can be used, depending on their physiological characteristics (for example: hardiness) and environmental site conditions. Periodic harvesting can continue over a period of approximately 20 years, after which the stumps must be removed. Average yield ranges between 6 and 12 odt/ha/year.

References

Keoleian, G.A.; Volk, T.A. 2005. Renewable energy from willow biomass crops: Life cycle energy, environmental and economic performance. Crit. Rev. Plant Sci. 24:385-406.

Labrecque, M.; Teodorescu, T.I. 2006. La culture intensive de saules en courtes rotations (CICR). Institut de recherche en biologie végétale et Jardin botanique de Montréal, Montréal, Quebec. 4 p.

A 3-year-old concentrated hybrid poplar plantation (2007)

A 3-year-old concentrated hybrid poplar plantation (2008)

A 3-year-old concentrated hybrid poplar plantation (2009)

Aerial view of a 3-year-old concentrated hybrid willow plantation (2010)

Description

Dedicated SRWC high-yield afforestation systems of hybrid poplar or aspen involve area-based plantations characterized by moderate planting density (1,100–1,600 cuttings/ha), a 15- to 20-year harvesting cycle, and typically a single rotation before large stem harvest/recovery. Mean yield ranges between 13.6–20.0 m3/ha/yr (5–8 odt/ha/yr).

1-year-old high-yield afforestation plantation of hybrid poplar (2010)

6-year-old high yield afforestation plantation of hybrid poplar (2010)

Description

Linear rows of fast-growing poplar or willow planted adjacent to a water body with the primary intent of regulating the movement of materials in surface runoff and groundwater that flows from uplands to streams and providing biomass feedstock for bioenergy. As with short-rotation woody crop systems of willow, the harvesting cycle can be as short as 3–4 years. In this way, both stream bank protection and biomass production can be achieved. In Canada, willow-based riparian buffer systems have been developed over approximately the past 5 years.

References

Fortier, J.; Gagnon, G.; Truax, B.; Lambert, F. 2010. Biomass and volume yield after 6 years in multiclonal hybrid poplar riparian buffer strips. Biomass Bioenergy 34:1028-1040.

Tufekcioglu, A.; Raich, J.W.; Isenhart, T.M.; Schultz, R.C. 2003. Biomass, carbon and nitrogen dynamics of multi-species riparian buffers within an agricultural watershed in Iowa, USA. Agrofor. Syst. 57:187-198.

Willow riparian buffer planted adjacent to water drainage channel.

Aerial view of willow riparian buffer project in Prince Edward Island.

Three year old willow riparian buffer in Prince Edward Island planted at a density of 4000 stems/hectare.

Description of the system

In willow- or hybrid poplar-based alley cropping systems, shrubs and/or trees are grown in single or multiple rows at a relatively wide spacing between the rows to leave room for crops to be grown in alleys. This approach seeks to take advantage of positive ecological interactions between trees or shrubs in rows and alley species, especially at the soil and light levels. In Canada, R&D on willow- or hybrid poplar-based alley cropping systems began about 6 years ago.

References

Garrett, H.E.; McGraw, R.L. 2000. Alley cropping practices. Pages 149-188 in North American Agroforestry: An Integrated Science and Practice. H.E. Garrett, W.J. Rietveld, and R.F. Fisher, eds. American Society of Agronomy Inc., Madison, WI.

Williams, P.A.; Gordon, A.M.; Garrett, H.E.; Buck,  L. 1997. Agroforestry in North America and its role in farming systems. Pages 9-84 in Temperate Agroforestry Systems. A.M. Gordon and S.M. Newman, eds. CAB International, Wallingford, U.K.