Mixed indigenous species plantations in Ghana

Compiled by: P.P. Bosu, J.R. Cobbinah, B. Darko-Obiri, E.E. Nkrumah, S.S. Stephens & M. R. Wagner

Most forest plantations all over the world have been established using monoculture or single-species approach. Plantations consisting of two or more species on the same site, otherwise known as mixed-species plantations (or polycultures) are very few by comparison. One does not need to be an expert to figure why most tree growers prefer monoculture over mixed-species or polyculture systems. To a large extent, the motivation for most individuals or corporations to undertake tree plantation projects is economic. The objective may be to produce timber for construction, manufacture of furniture or some other secondary wood products. Plantations may also be established with the aim of producing utility poles, or raw materials for the manufacture of pulp and paper products. As the economic or financial return is key in all these ventures efforts are made to maximize the production of wood fibre with as little an investment as possible. Under such operational conditions, monoculture plantations are often preferred because of relative ease to establish and manage whether under small, medium or large-scale operations.

Why then are mixed-species planting necessary?

There are many reasons why mixed-species plantations are needed and should be promoted.

  1. Mixed-species plantations are widely acclaimed as more environmentally friendly and sustainable forest plantation systems than monoculture plantations. Mixtures of especially indigenous species are regarded as being ecologically closer to 'natural' forest ecosystems than monocultures
  2. Mixtures also have some economic and social advantages over monoculture plantations.  Undoubtedly, there are also challenges in the management of mixed species plantations but within the context of this handbook the advantages are over and above those disadvantages.

The preparation of this handbook follows the successful execution of the International Tropical Timber Organization (ITTO) Project on mixed native species plantations which was executed in Ghana (PD 256/03 Rev. 1(F)).  It provides technical and socio-economic basis for establishing and managing mixed species plantations in Ghana and tropical Africa in general.