Pesonen will take the post on January 1, with Wiersum becoming vice-chairman for the next two years.
According to Pesonen the EU needs a competitive forest fibre industry in order to meet its carbon neutrality goals.
He said: "The forest fibre industry is the leading producer of bioenergy and renewable wood-based bio-products in Europe.
"European consumers are most definitely interested in seeing positive progress in substituting oil-based products with renewable and recyclable bio-products. Therefore European policy makers should ensure a competitive operating environment for this industry."
"We need the continued carbon-leakage status for 2015-2020 to remain competitive. Also the EU Renewable Energy Policy, by subsidising biomass for energy use, threatens the supply of essential raw materials for our industry. At a regional level, the sulphur directive of marine fuels increases transport costs in Northern Europe to uncompetitive levels."