AbstractWe examine the interaction between the relative inter‐industry pollution externality and resource stock externality of harvesting in deciding trade patterns and welfare gains from trade in a two‐country model (less‐developed countries) with renewable resources in the absence of resource management. This paper focuses on the impacts of trade policies on resource conservation and welfare outcomes in two countries with different environmental management regimes. Differences in pollution management standards between both countries determine the direction of trade flow and gains from trade in a diversified production case. The country with a lower pollution intensity parameter, an exporter of resource goods, certainly experiences welfare loss in the post‐trade steady‐state and may also suffer a decline in utility throughout the transition path. However, a country with higher pollution intensity and importers of resource goods tend to gain from trade. Under national open‐access resources, given that pollution is regulated up to a certain point in both countries, this study finds that implementing better restrictions on only one externality factor is not optimal from a post‐trade welfare perspective. Lastly, from the point of view of policy suggestion, this paper offers an optimal trade policy that the economic and environmental effects of enforcing import tax on resource goods are likely to be Pareto‐improving consequences compared to the implications of using an export tax.