The monoterpenes emitted from a Monterey pine (Pinus radiata) were investigated using a dynamic flow-through enclosure technique. The monoterpenes identified and quantified were α- and β-pinene, d-limonene+β-phellandrene, myrcene, camphene and Δ3-carene, with α- and β-pinene accounting for over 80% of the total monoterpene emissions. The monoterpene emission rate increased with temperature, in good agreement with previous data for other coniferous species. The absence of added CO2 to the synthetic air flow stream, exposure to elevated levels (300--500 ppb mixing ratio) of O3 for 3--4 hours, and increased air movement within the enclosure had no observable effect on the monoterpene emission rate at a given temperature. In contrast, ''rough handling'' of the pine during the sampling protocol resulted in increases in the monoterpene emission rate by factors of 10--50. These results will be useful to those designing enclosure sampling protocols for the determination of the emission rates of biogenic organic compounds from vegetation.