Date palm (Phoenix dactylifera L.)

The date palm (Phoenix dactylifera L.) is an emblematic plant of the arid regions of the Arabian Peninsula where it constitutes the key species in traditional date palm gardens. It has been grown by local populations for almost 5000 years and might even have been domesticated in this part of the Middle East.

The multi-purpose “tree”

The date palm belongs to the large family of palms (Areacaceae or Palmae in Latin) and shares the main characteristics of other members of this group. Despite its size (it can grow up to 30 m high) and tree-like habit, the date palm is not a tree in the true botanical sense of the word and its stem, called trunk, is not made of wood like those of trees and shrubs. The large feather-like leaves (3-5 m long) are compound, with numerous leaflets inserted on each side along a central midrib, and form a wide crown at the top of the stem (Fig. 1). To botanists the date is a berry, that is a fleshy fruit containing – in this case – a single lignified seed. The dates are borne in large bunches with yields that can attain 30-100 kg per tree (Fig. 2).

The date palm is a so-called dioecious plant with female and male inflorescences occurring on separate individuals. In natural populations, the proportions of female and male trees are more or less equal (50 % each) and pollination is usually carried out by the wind even though insect-pollination may occur occasionally (Fig. 3). In cultivated date palm gardens, fruit-bearing female trees are preferred over male palms and only a few pollen-producing individuals are kept for yearly fecundation. Pollination then has to be carried out artificially, that is by humans who first climb up male trees to gather mature inflorescences before bringing these to the top of female palms where the pollen is sprinkled over the flowers, an act that ensures the development of fruit within a few months (Fig. 4).

The cultivation of date palms is to a large extent based on vegetative multiplication, that is the cloning of desired morphotypes. Basal shoots or suckers naturally form at the base of the palms and if not cleared they grow into supplementary stems flanking the original trunk. When such shoots develop at the base of a cultivated female palm producing good quality fruits, they are tended, protected and finally separated from the mother tree before being transplanted elsewhere in the garden. These young palms are genetically identical to the original palm (they are clones) and will strongly resemble their unique parent, for example when it comes to fruit characteristics. Occasionally, individuals grown from seeds are also cultivated but the result of sexual reproduction is much less predictable because of the genetic diversity induced by cross-pollination. Vegetative reproduction using basal shoots is an ancient practice in the Middle East described in cuneiform texts from southern Mesopotamia and even depicted on a fragment of a soft stone vessel from the Bronze Age palace of Mari, Syria (Tengberg 2012: 144).

Besides its precious and abundant fruits, rich in sugar and vitamins, practically every part of the date palm is useful for various purposes. The stem and woody midribs of the leaves can be used for construction work (Fig. 5) and as fuel. The latter are also transformed into furniture and small boats and are frequently used as a medium for inscriptions in southwest Arabia [See cursive inscriptions]. The large leaves are used for covering roofs and the construction of huts. The leaflets are transformed into basketry, matting and cordage and the rough fibres surrounding the base of the leaves (fibrillum) are employed for making ropes and baskets as well as for packaging and padding (Fig. 6).

Beyond these direct and valuable uses, the date palm also constitutes the main species and structural element in date palm gardens. The large fronds of adult trees ensure protection from the hot sun and thus allow the cultivation of other crops on lower levels (Fig. 7). Traditionally, these are organised according to several vertical strata with annual crops being cultivated on the ground and medium-sized fruit trees (fig trees, pomegranate, olive, lemon, etc.) forming an intermediary level between these and the date palms. Horizontally, date palm gardens can be organised in many different ways with plots and fields alternating with irrigation canals and more and less permanent constructions. Similarly, date palms can either grow in cultivated fields or rather around their borders depending on the spatial organisation of the garden. In any case, traditional palm gardens in Arabia, as elsewhere in the arid Middle East and North Africa, are known to host a large array of species, ranging from cereals, pulses, vegetables and herbs to cash crops such as tobacco and cotton. Crops can be cultivated together in the same fields but also successively according to annual rotations where winter crops (for example wheat, barley, potatoes) follow on from summer crops (millets, sorghum, tropical pulses, etc.).

Early use and domestication of Phoenix dactylifera

The tools at our disposal for reconstructing the early history of date palm use and cultivation mainly belong to two fields of study: archaeobotany and genetics. Remains of date palm are found at many archaeological sites in the Arabian Peninsula from Prehistory to modern times. Macrobotanical remains such as fruits, seeds, stem and leaf fragments are usually preserved in a carbonised state due to their exposure to fire (Fig. 8), either by accidental burning or due to their use as fuel. Microfossils (pollen, phytoliths) from date palms are recovered from sediment samples collected from settlements or natural sites and bear witness to their local presence and use. The analysis of gene sequences of present-day Phoenix dactylifera varieties allows us to understand the phylogenetic relationship between different forms and provides new clues to the still elusive domestication process of Phoenix dactylifera (Gros-Balthazard et al. 2018).

The earliest evidence for the use of date palm in the Arabian Peninsula comes from two Neolithic settlements in the Persian Gulf region: H3 (as-Sabiyah) in Kuwait and Dalma in Abu Dhabi, where date seeds have been recorded and radiocarbon dated to the late 6th and early 5th millennia BCE (Beech 2003). Even though it is likely that these early date fruits were collected from the wild, they raise questions about the initial distribution and the subsequent domestication of the species. In the absence of truly wild date palm populations, the distribution of Phoenix dactylifera and the potential regions of its first domestication have been the subject of much speculation (Gros-Balthazard et al. 2013). The recent discovery of what seems to correspond to authentic wild populations in Oman suggests however that the date palm might have had a wide natural distribution in the Middle East with the possibility of local domestications in several regions, including the Arabian Peninsula (Gros-Balthazard et al. 2016).

The development of date palm cultivation in the Arabian Peninsula

The first evidence of the cultivation of date palm in the Arabian Peninsula dates to the early 3rd millennium BCE and comes from the site of Hili 8, situated in the oasis of al-Aïn in the Emirate of Abu Dhabi (UAE) (Cleuziou and Costantini 1980). Date palm is well represented in archaeological contexts by both seeds and fragments of the fibrous tissue found in palm stems and leaves. Moreover, the association of date palm remains and other crops, such as cereals and pulses, in an environment where rain-fed agriculture seems out of the question, suggests that cultivation took place in irrigated date palm gardens.

Throughout the early Bronze Age and in particular during the Umm an-Nar period (c. 2700-2100 BCE), examples of oasis agriculture multiply in East Arabia. At Bāt, located in a wādī in the Oman Mountains, date palm remains are associated with mud brick impressions of free-threshing wheat and barley. Several sites along the Persian Gulf coast, such as Umm an-Nar and Tell Abraq (UAE), have also produced evidence of date palm together with annual crops (Tengberg 2012). Date palms are moreover attested in the northern part of the peninsula, as shown by recent research in present-day Saudi Arabia where sites located in the valley of al-ʿUlā and dated to the late 2nd millennium BCE have yielded seeds as well as leaf and stem remains (Rohmer et al. 2022).

Date palms and date palm gardens continued to play a central role in Arabian agricultural production systems up to the modern era, with archaeobotanical remains of Phoenix dactylifera being ubiquitous on sites from the Iron Age, Antiquity and Islamic times. The presence of numerous seeds and fruits bears witness to the importance of the species in local diets. Dates were probably also used as fodder, a practice known from historical sources and still in use today.

Even though direct evidence is scarce, date fruits and sweetening products derived from dates are likely to have been exported to neighbouring regions. Mesopotamian cuneiform texts for example mention a special brand of “Dilmun dates”, thought to have originally come from the island of Bahrain. A sort of date syrup or ‘honey’ was prepared in special rooms where ripe dates (in clusters or in bags) were placed on a plastered floor with channels leading to a recipient in which the sweet liquid exuding from the disintegrating fruits was collected. An example of such a room, traditionally known as a madbasa in the Persian Gulf region, was discovered in an early-2nd-millennium context at Qalʿat al-Bahrain on the island of Bahrain (Højlund 1990, fig. 9).

Finally, dates could also accompany the dead on their ultimate journey as shown by the discovery of stoned date fruit preparation in a collective burial pit from the Umm an-Nar period at Hili North in the United Arab Emirates (Méry and Tengberg 2009).

Margareta Tengberg

References and suggested readings

• Beech, M. 2003. Archaeobotanical evidence for early date consumption in the Arabian Gulf, in The date palm – from traditional resource to green wealth: 11-31. Abu Dhabi: The Emirates Centre for Strategic Studies and Research.
• Bouchaud C., R. Thomas & M. Tengberg 2012. Optimal use of the date palm (Phoenix dactylifera L.) during antiquity: Anatomical identification of plant remains from Madâ’in Sâlih (Saudi Arabia), in E. Badal (ed.) Wood and charcoal. Evidences for the human and natural history (Saguntum-Extra, 13): 173-185. Valencia: University of Valencia.
• Cleuziou, S. & L. Costantini 1980. Premiers éléments sur l’agriculture protohistorique de l’Arabie orientale. Paléorient 6: 245-251. DOI: 10.3406/paleo.1980.4278.
• Gros-Balthazard, M., C. Newton, S. Ivorra, M. Tengberg, J.-C. Pintaud & J.-F. Terral 2013. Origines et domestication du palmier dattier (Phoenix dactylifera L.). Etat de l’art et perspectives d’étude. Revue d’ethnoécologie 4. https://ethnoecologie.revues.org/1216
• Gros-Balthazard, M., C. Newton, S. Ivorra, M.-H. Pierre, J.-C. Pintaud & J.-F. Terral 2016. The domestication syndrome in Phoenix dactylifera seeds: towards the identification of wild date palm populations. PLoS ONE 11(3): e0152394. DOI: 10.1371/journal.pone.0152394.
• Gros-Balthazard, M., K.M. Hazzouri & J.M. Flowers 2018. Genomic insights into date palm origins. Genes 9(10): 502. DOI : 10.3390/genes9100502.
• Højlund, F. 1990. Date honey production in the mid 2^nd millennium BC. Steps in the technological evolution of the madbasa. Paléorient 16(1): 77-86. DOI: 10.3406/paleo.1990.4520.
• Méry, S. & M. Tengberg 2009. Food for eternity? The analysis of a date offering from a 3^rd millennium BC grave at Hili North, Abu Dhabi (United Arab Emirates). JAS 36(9): 2012-2017. DOI: 10.1016/j.jas.2009.05.017.
• Rohmer, J., F. Lesguer, C. Bouchaud, L. Purdue, A. Al-Suhaibani, F. Tourtet, H. Monchot, et al. 2022. New clues to the development of the oasis of Dadan. Results from a test excavation at Tall al- Sālimīyyah (al-ʿUlā, Saudi Arabia), in R. Foote, M. Guagnin, I. Périssé & S. Karacic (eds) Revealing Cultural Landscapes in Northwest Arabia. Supplement to the Proceedings of Seminar for Arabian Studies: 52: 155–88. Oxford: Archaeopress. https://cnrs.hal.science/hal-03930118/
• Tengberg, M. 2012. Beginnings and early history of date palm garden cultivation in The Middle East. Journal of Arid Environments 86: 139-147. DOI: 10.1016/j.jaridenv.2011.11.022.

_{Alternate spellings: Palm tree, Palm-tree, Palm, Palmgrove}