It is unlawful to cause or permit the emission of dense smoke from any fire, chimney, engine, oil burner, or any other agency in the village so as to cause annoyance and discomfort to the residents thereof; provided, however, that upon obtaining appropriate permission from fire district officials, burning shall be allowed in areas designated as wetlands for the purpose of maintaining, preserving, and improving the quality of the wetland ecology. (1990 Code §13.113)