Acacia and its competitors
Sustainable - Ecological - European - Quality Wood
According to the European standard, acacia wood is the only European specie suitable for use in risk class 4 "Outdoor use in contact with soil and fresh water exposed permanently to moisture" just as some tropical species such as Iroko and Ipe. Nevertheless these tropical woods arrive in Europe after thousands of kilometers traveled which impacts their carbon footprint. In addition, the management of some of these forests is not always respected. At the European level, two species try to compete with acacia wood, these are oak and chestnut. However these two species are classified in class of risk 3. They can be used outside, but without contact with soil and permanent humidity.
For use as wood poles and therefore a wood subjected in contact with the ground permanently, it has been proven that an oak stake will have a life of about 15 years, at the same time chestnut stakes will have a life of 20 years while acacia poles will have no problems for 60 years. Therefore it is generally accepted that it will take 4 oak stakes or 3 chestnut stakes to match an acacia pole durability.
The chestnut specification document prepared by the Center for International Cooperation in Agricultural Research for Development (CIRAD), provides information on its characteristics in terms of its sustainability. The tables below allow us to compare acacia wood with its main European 'competitor', the chestnut tree.
For the same usage, other materials can be used: PVC, metal or concrete. Although they have good characteristics such as durability, these materials are more expensive, do not blend in natural landscapes and have a very negative carbon impact.
The table below compares the different materials that can be used for the production of poles:
Oak has good natural characteristics, however it is one of the most expensive wood specie on the market.
The chestnut has good durability but has a shorter life span than acacia. Concrete will require little maintenance but is seen "aggressive" in the landscape. PVC is the most economical solution, however it is unattractive and not very resistant. Stone is the most durable solution, however its price is the bigest. Steel will blend in with the environment, but will remain more urban than a wooden fence and will require more maintenance. Spruce is a softwood, mostly for outdoor use (like other wood class 1 to 3), must undergo autoclave treatments, making it resistant to water and fungi lignivore species. However, these treatments leave a strong ecological footprint.