Nine provenances of Turkish red pine (<i>Pinus brutia Ten</i>.), an eastern Mediterranean conifer, taken from a wide range of locations in Turkey, were grown in individual pots in a greenhouse either with or without joint goose goatgrass (<i>Aegilops cylindrica</i> L.) under either high or low soil water availability for two growing seasons. The study consisted of two separate experiments started at times with varying microenvironmental conditions and Turkish red pine (TRP) provenances. Diameter and secondary needle, stem, and root biomass were measured at the end of the second growing season, while height was measured after both the first and second growing seasons. Pine stem water potential (SWP), measured at the end of the second growing season, was the only physiological variable in the study. / Master of Science