Poplars

Poplars

  • In the Northern Hemisphere, about 35 species of the Poplar family Populus live in the temperate zones.
  • In Britain there are certainly two native members of the poplar family - the aspen P. tremula and the black poplar P. nigra var betulifolia; the grey poplar P. x canescens may be native in southern Britain too.
  • Here, poplars are at the northern limit of their natural distribution and do not grow well outside southern Britain.
  • In Britain, some are grown for their wood but many are planted for screening, shelter or ornament.
  • The well-known Lombardy poplar is a fastigiate or elongated variety of P. nigra, planted for ornament and windbreaks.
  • Growing poplars for timber is very profitable in parts of mainland Europe and other places well suited to their growth.
  • Poplar species hybridise freely, making it difficult to identify some forms and species.
  • Poplars grown for timber include various crosses between the European poplar P. nigra and two N. American species P. trichocarpa and P. deltoides.

    • Poplar foliage © J. Jackson

  • There are numerous cultivated hybrids, varieties and clones which are propagated vegetatively from cuttings or sets.
  • There are about 14,000 ha of poplars in Britain, less than 1% of the total forest area. About half is in East Anglia.
  • Many poplar plantations in Britain were originally planted to produce wood for matchsticks but those are imported now.
  • Poplar can be used for joinery and even musical instruments but it is not one of the best hardwood timbers. Poplar wood is ideal for peeling into thick veneers.
  • Fruit punnets were made from poplar before plastic replaced them.
  • The result of many years of traditional plant breeding, testing and selection, new types of poplar are being introduced into Britain mainly from Belgium. The new varieties grow faster and reach a commercial size at 12-15 years compared to the older types at 22 years.
  • Most poplars flower in early spring but they are normally propagated from cuttings in open nursery beds.
  • Poplars do best on high fertile, base-rich, loamy soils or rich alluvial or fen soils which are well drained and aerated and moist year long with a high water table. Banks of streams and alluvial river valley soils are very suitable.
  • Poplars are light-hungry so are planted at very wide spacing, normally 8 x 8m apart. Young stock needs weeding and protecting from squirrels, livestock, rabbits and deer.
  • To produce knot-free timber, pruning is necessary to remove the side branches.
  • Poplar is a good species in agroforestry systems.
  • Poplars are susceptible to a number of diseases and attacks by insects.
  • There is a lot of recent interest in growing poplars as short rotation biomass crops for producing energy, particularly in countries which do not have large reserves of fossil fuels.
  • A classic publication on poplars is the Forestry Commission Bulletin 92, "Poplars for Wood Production and Amenity" by J. Jobling published in 1990 by the HMSO.