1 Introduction 1.1 Environmental setting of the Early and Middle Bronze Age settlement of Tell Mozan The Northeast-Syrian multi-period site of Tell Mozan 1 has been occupied since c. 2800 BC. It is one of the few settle- ments with continuous habitation between the Early and the Middle Bronze Age, 2 and was a Hurrian capital in the third millennium BC. Excavations of its Early and Middle Bronze Age cultural layers by the team of Prof. Peter Pfälzner are elucidating the processes of urbanization in North-Mesopo- tamia during the third millennium BC. The site lies about 8 km south of the Turkish-Syrian border, in the north- eastern part of Syria on the Khabur plains, 3 north-east of the west-Syrian mountains that ind their eastern extension in isolated ridges of Jebel Abd el Aziz (920 m) and Jebel Sinjar (1.480 m). To the north, elevations increase continu- ously to more than 1.000 m at Turkish Mardin, 20 km from Tell Mozan. The diversiied climatic situation in Syria is characte- rized by the east Mediterranean coast in the west, the Anato- lian highlands in the north, and the large desert plains in the southeast. The Mediterranean element has hot and mainly rainless summers, and moist winters with moderate tempe- ratures. Summers are considered to have continental charac- teristics and, winters oceanic characteristics. 4 In summer the subtropic passat zone causes constant weather conditions, while during winter mainly cyclonic activity is responsible for strong regional differences between the coastal area and central Syria, resulting in distinctive climate regions (Figure 1b). Tell Mozan lies in the area of the northeast Syrian steppe climate, with comparatively high precipita- tion, resulting in only three to four rainless months during the summer. Precipitation is, due to its regional and seasonal diversity and inter-annual luctuations in its amount, the most impor- tant climatic factor in Syria. Plant survival in arid environ- 1 37°04’ N, 40°59’ E; 431 m asl. 2 See Bianchi – Geith – Dohmann-Pfälzner – Pfälzner – Wissing in preparation; Dohmann-Pfälzner – Pfälzner 1999, 2000, 2001; Pfälzner 1998; For younger periods see Buccellati – Kelly-Buccellati 1988, 1997, 1998, 1999; and also Doll this volume. 3 Near the headwaters of Wadi Dar’a. 4 Wirth 1971. ments is subject to chronic water limitation and rainfall vari- ability, resulting in the evolution of drought adaptation, for example in wild cereals. Landscape use and agriculture were always more dependent on precipitation than on tempera- tures, thus demonstrating the key role of precipitation in the cultural development of this territory. 5 January is the month of maximum precipitation in most places, followed by December in the west, and February in the east of the country. The mean actual precipitation in a series of drought years, such as between 1957 and 1961, may be 100 to 200 mm below the long-term mean annual precipitation, 6 causing a continuous sequence of crop failures in areas with long- term mean annual precipitation below the critical 400 mm isometer, if mixed rainfed agriculture with cereals and fruit trees is the main strategy. 7 Most of Syria’s Early and Middle Bronze Age sites lie in an area of 200 to 400 mm of modern mean annual precipita- tion, while mean annual precipitation at Tell Mozan is above 400 mm (Figure 1d). Recent research on the variation in the amount of precipi- tation shows reasonable evidence of multi-year to decadal cyclicity in precipitation patterns, 8 i.e., the occurrence of droughts for a duration of three years or longer. Conside- ring a scenario of several drought years during the Early and Middle Bronze Age under the assumption that modern and ancient mean precipitation are more or less equal, the settlements in regions below the critical 400 mm isohyet were under permanent risk of crop failure in occasional drought years, as, e.g., the large settlements along the middle Euphrates, if they had not applied irrigation. Particu- larly highly drought-resistant cereals, such as barley, may therefore have advanced to the main cereal crops under such climatic conditions. At Tell Mozan, with its long-term mean annual precipita- tion of ca. 460 mm, 9 rainfed agriculture should have been possible without serious losses in drought years. 5 Cf. Wilkinson 1997, 2003. 6 E.g. the 250 mm-isohyet in the considered drought years is equivalent to the 400 mm-isohyet of the long-term mean. 7 Wirth 1971. 8 Touchan et al. 2003; Touchan et al. 1999. 9 Qamishli – Wirth 1971. Plant Production in a Changing Environment: The Archaeobotanical Remains from Tell Mozan Simone Riehl