Short rotation coppice

Short rotation coppice (SRC) is coppice grown as an energy crop. This woody solid biomass can be used in applications such as district heating, electric power generating stations, alone or in combination with other fuels. Currently, the leading countries in area planted for energy generation are Sweden and the UK. Short rotation coppice (SRC) is coppice grown as an energy crop. This woody solid biomass can be used in applications such as district heating, electric power generating stations, alone or in combination with other fuels. Currently, the leading countries in area planted for energy generation are Sweden and the UK. SRC uses said high yield varieties of poplar and willow. Typically willow species chosen are varieties of the Common Osier or Basket Willow, Salix viminalis. Poplar is generally planted for visual variation rather than being a commercial crop, although some varieties can outperform willow on suitable sites. Species are selected for their acceptance of varying climate and soil conditions, relative insusceptibility to pests and diseases, ease of propagation and speed of vegetative growth. To combat pests such as brassy and blue willow beetles, as well as the fungal pathogen Melampsora (a rust), planting a carefully selected mix of varieties is recommended. The management of the plantations highly affects the productivity and its success. SRC can be planted on a wide range of soil types from heavy clay to sand, including land reclaimed from gravel extraction and colliery spoil. Where used as a pioneer species the SRC yield may be smaller. Water availability to the roots is a key determinant for the success of the SRC. Saplings are planted at a high density, as much as 15,000 per hectare for willow and 12,000 per hectare for poplar. Willow SRC can be established according to two different layouts. In most North European countries (Sweden, UK, Denmark) and in the US, the most frequent planting scheme is the double row design with 0.75 m distance between the double rows and 1.5 m to the next double row, and a distance between plants ranging from 1 m to 0.4 m, corresponding to an initial planting density of 10,000 - 25,000 plants ha−1. . In other countries like Canada, a single row design ranging from 0.33 m between plants on a row and 1.5 m between rows (20,000 plants ha-1) to 0.30 m on the row and 1.80 m between rows (18,000 plants ha-1) is more common .Planting takes place around March to take advantage of the high moisture of the soil in the spring and the amount of sunshine in the early summer. The most efficient planting machines plant four rows at a time and can plant a hectare in around three hours. Saplings are left to grow for one or two years and then coppiced. The primary barrier to establishing plantations is the cost as there is no financial reward for four years from a large initial investment. However, in the UK grants are available to support establishment, and in Sweden an extensive scheme of subsidies was developed during 1991-1996, being reduced after that time. Harvests take place on a two to five-year cycle, and are carried out in winter after leaf fall when the soil is frozen. The established root system and the nutrients stored in the roots and stumps guarantee vigorous growth for the shoots. A plantation will yield from 8 to 18 tonnes of dry woodchip per hectare per year. A plantation can be harvested for up to 20 years before needing to be replanted.