Social dilemmas require a choice between cooperation, or sacrificing for the greater good, and self‐interest. One commonly studied social dilemma is environmental conservation. Previous work suggests that trust predicts cooperation in the form of environmental protection. We contend that this view ignores cultural factors. Building on prior cross‐cultural research, we predict an interaction between strength of social ties and trust on cooperation. Findings from General Social Survey data indicate that low trust levels found in the U.S. South (a collectivist culture) renders trust ineffective at promoting environmental protection. However, trust predicts cooperation in nonsouthern regions (which are more individualist), where trust levels are higher.