classification as shown in Table 3.
„Hardwood Science and Technology”
The 5th Conference on Hardwood Research and Utilisation in Europe 2012
Table 3: Fiber length classification according to IAWA (1989) and Wagenführ (1984)
Species Mean values
Diospyros mespiliformis 0.975 M VS
Cassia fistula 0.929 M VS
Lannea schimperi 0.931 M VS
Boswellia papyrifera 0.912 M VS
Combretum hartmannianum 0.894 S VS
Azadirachta indica 0.834 S VS
Euphorbia tirucalli 0.832 S VS
Tamarindus indica 0.821 S VS
Eucalyptus camaldulensis 0.756 S VS
Tamarix aphylla 0.749 S VS
Dalbergia melanoxylon 0.561 S VS
*L = Long, M = Midium, S = Short and VS = Very short
The fiber diameter significant variations detected in the current study are in agreement with those found by OSMAN (2001) and RASHEED AND DASTI (2003). The highest mean values of fiber diameter were recorded for Adansonia digitata (34 μm), while the lowest mean value was found in Anogeissus leiocarpus (14.2 μm).
The study results are in accordance with OSMAN (2001), RASHEED AND DASTI (2003) who observed significant variation in fiber lumen diameter among species. The values of mean fiber lumen diameter of the studied species ranged from 4.8 μm in Anogeissus leiocarpus to 25.4 μm in Delonix regia. Concerning the fiber wall thickness, the significantly differences found in this study are in agreement with those of OSMAN (2001), but different than those of BABOS (1979) and RASHEED AND DASTI (2003) in which they didn’t find significant variation among species. The values of
The 5th Conference on Hardwood Research and Utilisation in Europe 2012
wall thickness varied from 2.8 μm in Gmelina arborea to 6.96 μm in Acacia sieberana.
In contrast to the slenderness ratio significantly differences found in current study, RASHEED AND DASTI (2003) didn’t find significant variation in slenderness ratio among twenty four plant species belonging to nineteen families. The highest mean value of slenderness ratio (89.1) was associated with Adansonia digitata and the lowest value (28) was associated with with Boswellia papyrifera.
In disagreement with the current study results RASHEED AND DASTI (2003) reported no significant variation in the values of runkle ratio among twenty four monocot and dicot species. Acacia gerrardii had significantly the highest mean value of runkel ratio (2.6), while Gmelina arborea had the lowest mean value (0.27). The flexibility coefficient significant variations detected in the current study are in agreement with those found by RASHEED AND DASTI (2003). The highest flexibility coefficient mean value (0.80) was in Gmelina arborea while the lowest mean value was in Acacia gerrardii (0.32).
CONCLUSION
Highly significant variations were found among species in all the investigated fiber characteristics. These variation leads to expect variation also in their end uses. Some of the study species have long fibers which are comparable with those of softwood. Almost all the study species have good slenderness ratio (> 33). Runkel ratios of more than twenty species are within the acceptable range for pulp and paper making of 0.25-1.5 as sited by VALKOMER (1969). While half the study species have values of more than 60 % flexibility coefficient which is acceptable for pulp and paper making as sited by (PETRI 1952, OKEREKE 1962 AND RYDHOLM 1965). The current study results promote the possibility of using the study species on forest industries.
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