text: Natural occurrence Coppice and pollard growth is a response of the tree to damage, and can occur naturally. Trees may be browsed or broken by large herbivorous animals, such as cattle or elephants, felled by beavers or blown over by the wind. Some trees, such as linden, may produce a line of coppice shoots from a fallen trunk, and sometimes these develop into a line of mature trees. For some trees, such as the common beech (Fagus sylvatica), coppicing is more or less easy depending on the altitude: it is much more efficient for trees in the montane zone.
  For energy wood
  Coppicing of willow, alder and poplar for energy wood has proven commercially successful. The Willow Biomass Project in the United States is an example of this. In this case the coppicing is done in a way that an annual or more likely a tri-annual cut can happen. This seems to maximize the production volume from the stand. Such frequent growth means the soils can be easily depleted and so fertilizers are often required. The stock also becomes exhausted after some years and so will be replaced with new plants. The method of harvesting of energy wood can be mechanized by adaptation of specialized agricultural machinery.
  Species and cultivars vary in when they should be cut, regeneration times and other factors. However, full life cycle analysis has shown that poplars have a lower effect in greenhouse gas emissions for energy production than alternatives.