Atmospheric composition, local climate and sapling gas exchange were monitored to assess the short-term effects of smoke-haze from the 1997 Indonesian forest fires. Atmospheric concentrations of particulate matter, SO2, CO, CH4 and CO2, and relative humidity were elevated, and photosynthetically active radiation and ambient temperature were reduced by the smoke-haze. Despite elevated CO2 levels, photosynthesis in three tree species was reduced by the smoke-haze, both indirectly through reduced PAR levels, and directly through elevated aerosol and atmospheric pollutant levels.