Industrial Crops and Products 37 (2012) 200–206 Contents lists available at SciVerse ScienceDirect Industrial Crops and Products journa l h o me pag e: www.elsevier.com/locate/indcrop Variations in the morphological characteristics of Stipa tenacissima fiber: The case of Tunisia Samia Belkhir a,b,∗ , Ahmed Koubaa b , Ayda Khadhri a , Mustapha Ksontini c , Samira Smiti a a University of El-Manar II, Faculty of Sciences, Unity of Research of Vegetal Ecology, Campus Academia, 2092 Tunis, Tunisia b Canada Research Chair on Wood Development, Characterization and Processing, Université du Québec en Abitibi-Témiscamingue, Rouyn-Noranda, QC, J9X 5E4, Canada c National Institute of Research in Farming Genius, Waters and Forests, 2080 Tunis, Tunisia a r t i c l e i n f o Article history: Received 4 May 2011 Received in revised form 8 November 2011 Accepted 11 November 2011 Keywords: Esparto (Stipa tenacissima) Morphological characteristics Pulp Biology Variation Environment a b s t r a c t Esparto fibers are cellulose-based fibers extracted from esparto (Stipa tenacissima) leaves. Morphologi- cal characteristics (length, width, and coarseness) of esparto fibers are analyzed in relation to growing conditions and plant biology. Seven localized sites in Kasserine in central western Tunisia are examined. The analysis of variance showed that all investigated characteristics vary significantly with site, season, and leaf level. Leaves reach minimum level in winter and maximum level in fall. Fiber differentiation is closely related to the vegetative cycle. Fibers are short and wide at the leaf base (basal level) and grow longer and thinner above the leaf. Results on the raw material (esparto leaves) were confirmed by results on esparto pulp. © 2011 Elsevier B.V. All rights reserved. 1. Introduction Stipa tenacissima, or esparto grass (Alfa), is a fast-growing peren- nial plant that thrives in dry areas of North Africa and southeast Spain (Cerda, 1997). It belongs to the poaceae family. Its fiber- rich leaves can reach 1 m in length. The tufts of S. tenacissima are circular and homogeneous when young but become empty at the center as they age and begin to die. The leaves are thin, ribbon-like, smooth, shining, solid, and covered at the base with a hairy sheath. Esparto leaves mature in the fourth to eleventh month after budding, depending on location and climatic con- ditions (Ghrab, 1981). For example, in Tunisia, the leaves of S. tenacissima take from four to six months to mature in the Thelepte region, which belongs to the arid superior bioclimatic stage. On the other hand, they take from eight to eleven months in the Nadhour region, which belongs to the arid lower climatic stage (Ghrab, 1981). According to Harche (1978), the biological cycle of S. tenacissima comprises two growing seasons (fall and spring) and two latent seasons (winter and summer). In fall the esparto tufts are in full vegetative phase. Thus, most leaves are mature, and the younger ∗ Corresponding author at: University of El-Manar II, Faculty of Sciences, Unity of Research of Vegetal Ecology, Campus Academia, 2092 Tunis, Tunisia. Tel.: +216 99 973 600. E-mail address: samiabelkhir@yahoo.fr (S. Belkhir). ones start to develop and lengthen. However, in winter most leaves are young and the growth halts due to the cold weather. In spring, the season of inflorescence, flowering generally begins in May and finishes at the end of June (Mehdadi et al., 2006). Early flowering may be observed in April if the previous autumn rains were suffi- cient and the winter was warm. Thus, flowering varies according to the location and the variability of climatic conditions over the years (Ghrab, 1981). In an ecological study, it was shown that esparto grass grows in almost all the geomorphological units, regardless of land typog- raphy. It even clings to rocky hillsides. However, the most dense and spatially extended populations are found in low-lying areas and on permeable glacis (Ghrab, 1981). Besides, in edaphic terms, esparto grass grows in shallow, permeable, calcareous soil with a very sandy texture and less well in clayey, salty soil. According to Pouget (1980), esparto prefers a stony soil with high calcareous content (30–40%) and low gypsum content (∼2%), and does not adapt well to soils with clay and loam content ranging from 12 to 20% (Ghrab, 1981). Moreover, Esparto grass thrives in a wide range of bioclimates and is resistant to large variations in tempera- ture. Nonetheless, it achieves optimum growth in arid superior and semi-arid lower bioclimatic stages (Ghrab, 1981; Nabli, 1989). The uses of this plant are very diverse. Indeed, it is used to make handcrafted espadrilles and baskets (Akchiche and Messaoud Boureghda, 2007), as alternative livestock feed during periods of forage scarcity (Genin et al., 2007), and to manufacture rope and mats. Furthermore, this plant serves as an invaluable natural barrier 0926-6690/$ – see front matter © 2011 Elsevier B.V. All rights reserved. doi:10.1016/j.indcrop.2011.11.021