The date palm biodiversity is obvious all around the world where about 5,000 date palm cultivars can be found (Jaradat and Zaid 2004). Based on botanical descrip­tions, about 1,000 cultivars can be found in Algeria, 400 in Iran, 370 in Iraq, 250 in Tunisia, 244 in Morocco, and 400 in Sudan, as well as many additional cultivars in the other countries (Benkhalifa 1999; Osman 1983; Zaid and De Wet 1999). The date palm trees (Phoenix dactylifera L.) is the tallest Phoenix species, it can be found with heights of more than 30 m and has fruit reaching up to 100 mm x 40 mm in size. The fruits are very tasty and nutritious (Jaradat and Zaid 2004). Date palms have characteristics that adapt them to varied conditions. Date palm trees can grow well in sand, but it is not arenaceous. It can also grow well where soil water is close to the surface because they have air spaces in their roots. Although date palm tree can grow well in saline conditions, it can do better in higher quality soil and water. The leaves of the date palm are adapted to hot and dry conditions, but it is not a xerophyte and requires abundant water (Benkhalifa 1999; Jaradat and Zaid 2004).

The date palm tree is characterized by numerous offshoots produced at its trunk’s base. The trunk of the date palm tree is covered with persistent grayish leaf bases. It is surmounted by a handsome array of pinnate divided long leaves and needle sharp fronds. Usually, around 10-20 new leaves are produced annually. The leaves of the date palm are subtended by a cylindrical sheath of reticulate mass of tough, fibrous material, at their bases. These together form a tight protective envelope for the terminal bud (Benkhalifa 1999; Dakheel 2003). A young actively bearing date palm tree showing offshoots is shown in Fig. 1.2 and fruit of the date palm is seen in Fig. 1.3 . Detailed morphological traits of date palm tree leaf can be shown in Fig. 1.4. where different parameters of the leaf can be demonstrated like the leaf length, thickness, angle, length of leaflet part, rachis thickness, leaf lets number as well as others (Salem et al. 2008).

Once the date palms’ fruit are harvested, large quantities of date palm rachis and leaves wastes accumulated every year in agricultural lands of different countries. These amounts of important and valuable biomass wastes are of potential interest in different countries since they can be considered as new cellulosic fiber sources. Thus, innovative ways of valorizing this abundant renewable resource should be found (Chandrasekaran and Bahkali 2013). One of these ideas is to use such natural fibers in natural fiber composites suitable for different industrial applications. This can be one way of meeting the increasing demand in renewable and biodegradable materials. Therefore, the agricultural residues of date palms mainly rachis and leaves can be viewed as sources of reinforcing fibers for polymeric matrices in com­posite. The competitiveness of the date palm fibers in forming natural composites suitable for automotive industrial applications was demonstrated (Al-Oqla and Sapuan 2014). On the other hand, several studies proved that date palm fibers have the potential to be an effective filler in both thermoplastics and thermosetting mate­rials to be used in different industrial applications (Abdal-hay et al. 2012; Agoudjil et al. 2011; Al-Oqla and Sapuan 2014).

Key to the diagram

Parameter Label

Leaf length Leaf width Leaf angle Spinctcd part length Length of lcaflcted part Petiole width

Rachis thickness between the last spine and the first leaflet

Leaf lets number

Terminal leaflet length

Terminal leaflet width

Ventral angle of middle leaflet

Middle leaflet width

Middle leaflet length

Leaflets spacing index at the middle

Angle of leaflets on both sides of

terminal one

Spine number SN

Middle spine width WS

Middle spine length LS

PW

Fig. 1.4 Detailed morphological traits of date palm tree leaf (Salem et al. 2008)

Date palm tree can produce annually large number of natural fibers that can be utilized in different industries. It is estimated that the annual date palm agricultural wastes are more than 20 kg of dry leaves and fibers for each date palm tree (Al-Oqla and Sapuan 2014). Moreover, the date palm tree produces another type of wastes as date pits which are about of 10 % of the date fruits (Barreveld 1993). Unfortunately, these agriculture wastes are not properly utilized in any biological process or industrial applications, in most of countries, despite of their contents of potential amount of cellulose, hemicelluloses, lignin, and other compounds. Typical date palm fibers can be seen in Fig. 1.5.