Energy forestry

Energy forestry is a form of forestry in which a fast-growing species of tree or woody shrub is grown specifically to provide biomass or biofuel for heating or power generation.

The two forms of energy forestry are short rotation coppice and short rotation forestry:

  • Short rotation coppice may include tree crops of poplar, willow or eucalyptus, grown for two to five years before harvest.[1]
  • Short rotation forestry are crops of alder, ash, birch, eucalyptus, poplar, and sycamore, grown for eight to 20 years before harvest.

Benefits

The main advantage of using "grown fuels", as opposed to fossil fuels such as coal, natural gas and oil, is that while they are growing they absorb the near-equivalent in carbon dioxide (an important greenhouse gas) to that which is later released in their burning.[2] In comparison, burning fossil fuels increases atmospheric carbon unsustainably, by using carbon that was added to the Earth's carbon sink millions of years ago. This is a prime contributor to climate change.

According to the FAO, compared to other energy crops, wood is among the most efficient sources of bioenergy in terms of quantity of energy released by unit of carbon emitted. Other advantages of generating energy from trees, as opposed to agricultural crops, are that trees do not have to be harvested each year, the harvest can be delayed when market prices are down, and the products can fulfil a variety of end-uses.[3]

Yields of some varieties can be as high as 12 oven dry tonnes every year.[4] However, commercial experience on plantations in Scandinavia have shown lower yield rates.[5]

These crops can also be used in bank stabilisation and phytoremediation. In fact, experiments in Sweden with willow plantations have proved to have many beneficial effects on the soil[6] and water quality[7] when compared to conventional agricultural crops (such as cereal).

Problems

Although in many areas of the world government funding is still required to support large scale development of energy forestry as an industry, it is seen as a valuable component of the renewable energy network and will be increasingly important in the future.[8]

Growing trees is relatively water intensive.

The system of energy forestry has faced criticism over food vs. fuel, whereby it has become financially profitable to replace food crops with energy crops. It has to be noted, however, that such energy forests do not necessarily compete with food crops for highly productive land as they can be grown on slopes, marginal, or degraded land as well - sometimes even with long-term restoration purposes in mind.

See also

References
  1. "Establishing an SRC plantation".
  2. "Potential seen to develop short-rotation forestry for wood fuel".
  3. "Scientific Facts on Forests & Energy". GreenFacts Website. 2009-03-13. Retrieved 2009-03-25.
  4. Aylott, MJ; Casella, E; Tubby, I; Street, NR; Smith, P; Taylor, G (2008). "Yield and spatial supply of bioenergy poplar and willow short-rotation coppice in the UK". New Phytologist. 178 (2): 358–370. doi:10.1111/j.1469-8137.2008.02396.x. PMID 18331429. Archived from the original (PDF) on 2013-01-05. Retrieved 2008-10-22.
  5. Mola-Yudego, Blas; Aronsson, Pär (2008). "Yield models for commercial willow biomass plantations in Sweden". Biomass and Bioenergy. 32 (9): 829–837. doi:10.1016/j.biombioe.2008.01.002.
  6. Dimitriou, Ioannis; Mola-Yudego, Blas; Aronsson, Pär; Eriksson, Jan (2012). "Changes in organic carbon and trace elements in the soil of willow short-rotation coppice plantations". Bioenergy Research. 5 (3): 563–572. doi:10.1007/s12155-012-9215-1.
  7. Dimitriou, Ioannis; Mola-Yudego, Blas; Aronsson, Pär (2012). "Impact of willow Short Rotation Coppice on water quality". Bioenergy Research. 5 (3): 537–545. doi:10.1007/s12155-012-9211-5.
  8. "Stern Review on the economics of climate change". Archived from the original on 2006-12-09.
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