Timber in an archaeological context can be used to establish chronologies, to understand the history of architecture and to reconstruct cultural landscapes and natural vegetation in the past. In this study, we use the xylological identifications and radiocarbon dating results of five timber fragments recently discovered in three palaces or palace-like structures in Fars (SW Iran) dating back to the period of the Sasanian Empire (224-651 CE). We show that Qal'a-ye Dokhtar, a fortified palace to the north of Firuzabad, was constructed during the power transition from the Parthian to the Sasanian period. On the other hand, the so-called Palace of Ardashir I besides Firuzabad, was accomplished after the power takeover by the Sasanians and the political stabilisation of SW Iran under the reign of Ardashir I (224-240 CE) and his son Shapur I (240-270 CE). We also demonstrate that the `Palace of Sarvistan' was mainly used right after the fall of the Sasanian Empire during the first centuries of Islamic domination over Iran. The discovery of timber in stone-dominated Sasanian architecture adds information on timber use in the Late Antique Near East. Mediterranean cypress (Cupressus sempervirens L.) was the only timber found in Sasanian palatial architecture, and its use suggests that the tree was one of themajor cultivated elements in ancient `Persis' most probably for its shade, beauty and building timber, but possibly also for its symbolic significance and sacred status to the Zoroastrians. Cypress trees may have played a major role in Persian gardens since antiquity, along with plane trees. (C) 2017 Elsevier Ltd. All rights reserved.