Guus van Kouwenhoven was convicted at a court in The Hague but acquitted on war crimes charges.
The trader, who runs the Royal Timber Company and Oriental Timber Corporation, was found guilty of selling arms to former Liberian president Charles Taylor.
The court heard that Kouwenhoven was at the centre of a timber-for-arms trade between 2000-2003, when Taylor fled the country, with the trader allegedly receiving logging concessions in Liberia.
A UN report submitted to The Hague said militias formed by Kouwenhoven’s companies had allegedly taken part in massacres.
But the court ruled that there was insufficient evidence to show factual involvement and knowledge of this by the defendant.