The pulp-producing parent company of the eucalyptus lumber brand Lyptus recorded a net loss of US$50m during the first quarter.
Brazil-based Aracruz recorded net profits of US$116.9m a year earlier.
It was stung by the weakening Brazilian currency and increased costs.
Aracruz’s subsidiary Aracruz Produtos de Madeira produces Lyptus-branded lumber at a sawmill in Bahia state.