The impact of olive orchard abandonment and rehabilitation on pollen signature: An experimental approach to evaluating fossil pollen data

For millennia the olive was an important cultivated tree in the southern Levant, as evidenced by numerous archaeological finds and Holocene pollen assemblages. However, the impact of abandonment and rehabilitation of olive orchards (a recurrent historical process) on the fossil pollen record has not been studied. We documented quantitative differences in the olive pollen signature in a well-managed traditional olive orchard, an abandoned orchard, and an orchard rehabilitated after decades of abandonment, establishing the biological basis for understanding the olive pollen signature. The results indicate a strong decline in flowering and pollen production for decades following the cessation of cultivation and a rapid increase following rehabilitation. This strong response suggests that the fossil pollen curves are a reliable marker for determining the extent of olive oil production in ancient times. In terms of agricultural/economic efficiency, rehabilitation of an orchard takes much less time than establishing a new orchard. This could have been one of the reasons why the same sites were reoccupied during peaks of settlement activity in antiquity. The recent field results are compared to fossil pollen data from the Sea of Galilee during the Bronze and Iron Ages.