Vertical and Horizontal Cell Structural Appraisal of a 9-Year Cedrela odorata L. (Miliaceae) for Pulp and Paper Making

Paper is a material of importance in human life and produced from wood. However, is not all wood that have the qualities to be used for paper production. This study assesses the suitability of a 9-year old Cedrela odorata wood in both vertical (bottom to top) and horizontal (sapwood to heartwood) directions for pulp and paper making. Specifically, we evaluated the variations in fibre dimensions and other derived technical requirements needed for wood to be used for paper production. Franklin’s maceration process was adopted for the study. Collected data was subjected to statistical analysis using IBM Statistical Package for Social Sciences (SPSS) version 17.00. Mean fibre length was found to be short (i.e., ranged from 0.822 ± 0.142 mm – top heartwood to 1.142 ± 0.144 mm –base heartwood) which were all less than 1.6mm (1600μm). Runkel ratio was highest in top heartwood (0.26 ± 0.08); Flexibility Coefficient was highest in bottom sapwood (0.83 ± 0.05); and Slenderness Ratio was highest in bottom sapwood (49.18 ± 10.42). The derived fibre values were all within acceptable standard ranges for wood to be used for paper production: runkel ratio <1.0, Coefficient of Flexibility >75%, and slenderness ratio >33 indicating that the 9-year old Cedrela odorata hardwood in Ghana is a potential species to be used to produce pulp and paper of desired qualities, especially when it is mixed with other long fibre wood species. Thus, the 9-year fast grown Cedrela wood species is recommended for consideration among other known species for paper manufacturing in Ghana and elsewhere.


INTRODUCTION
Wood products especially fibre is reported to be one major DOI : https://doi.org/10.35702/msci.10008 product recognized in the socio-economic development in forest-based industries across the world on account of their applications in the pulp and paper industries [1]. This recognition is also emphasized by the important role papers play in the lives of human beings in the areas of human and environmental sanitation, communication and Secretaryship, mother care, health care etc. However, in recent times, inadequate fibre has been identified as one of the major challenges facing the pulp and paper industries [2]. Though paper is made from wood, it is not all wood species that have the fibres which Conform to the desired qualities to be accepted for pulp and paper production.
For a wood species to be classified as a material for pulp and paper, its growth rate should be rapid for economical plantation management, the fibre it produces should be longer than average fibre length, the runkel ratio of the fibres should be less than 1, it should have low basic density, low ash content and low chemical extractives [3]. Thus, it is said that the quality of pulp and paper products is contingent on the morphology of the fibres and the chemical composition of the wood species [4]. Additional qualities of importance for considerations are that the species should have straight boles which aid debarking, and high fibre to non-fibrouis tissue ratio [5]. Thus, it is always important that more and more wood species are assessed in terms of the qualities expected of a potential pulpwood in order to recommend such species to augment the supply of fibre for the pulp and paper industry.
For some years now, Cedrela odorata species, a member here of the family Meliaceae has been planted in plantation forests in most regions of Ghana [6]. However, studies on the morphology (i.e., the anatomical cells characteristics) of the species in Ghana, especially in relation to vertical and horizontal variations and directed towards evaluation for paper production are either limited or unavailable. It is in this light that our present study focused on the variations in some anatomical characteristics of a 9-year C. odorata, at different vertical (bottom to top) and horizontal (sapwood to Heartwood) positions to ascertain the species' suitability for pulp and paper production.

Sampling site and Sampling
A total of five 9-year old Cedrela odorata trees were felled, extracted from Tano-Offin reserve, and processed. This reserve is the largest among four in the Atwima Mponua District of Ghana, and it has the following descriptions (Table 1).

Vegetation
Temperature Average  to which a few crystals of potassium chlorate (KClO3) had been added. After teasing the macerates in glycerol, the fibre morphological measurements were taking ( Figure 1) using Image J software (National Institute of Health, Bethesda, MD, USA).

Humidity Average Precipitation Geology
Where FL is the fibre length (µm); FWT is the fibre wall thickness (µm); FD is the fibre diameter (µm); and FLD is the fiber lumen diameter (µm).

STATISTICAL ANALYSIS
Data collected were subjected to Student's T-test (with SPSS 17.0) to ascertain whether or not there are significant differences between the obtained values (vertical and horizontal samples).

Variations in Fibre Morphological Characteristics
At who observed similar trend. It is reported that, wood fibres of lengths above 1.6mm (1600.00 μm) are considered to be long fibres [8]. It could therefore be said from this present study that, Cedrela odorata has short fibres with fibre lengths ranging from 0.822 μm to 1.142 μm - Table 2).
Long fibres have been found to produce paper with higher tear resistance [8,9]. Therefore, C. odorata papers may have low resistance to tearing, but the short fibres also tend to produce fine sheet structured paper [10]. Hence, though C. odorata may not produce papers of high tensile strength but it will produce papers of fine structure. Findings also indicate that, some grades of printing and writing papers need a mixture of both short and long fibres together in order to yield good printability and opacity [2].
From the foregoing, at least, the C. odorata wood (short fibre wood) could be mixed with some other wood with long fibres so as to produce papers of a better improved qualities.  Generally, according to the standards, RR should be <1 and is considered most suitable for producing paper with desirable qualities. Fibres that have FC ranging from 0.50 to 0.75+ are also considered to be highly elastic. Such are the desired qualities of wood species suitable for paper making, especially paper of good tensile and bursting strengths [1,11]. SR should be >33 to be able to produce paper with acceptable qualities [12,13]. Hence, the SR range of 38 -49 for C. odorata (Table 3) is also a favourable indicator that the 9-yrs tree fibres are better materials to produce paper of good quality.

CONCLUSIONS AND RECOMMENDATIONS
From the foregoing analysis and discussions, we conclude and recommend that 9-year C. odorata wood species in Ghana is a potentially good material to produce paper of desired qualities. There appears to be varied consistencies in vertical (from bottom to top) and horizontal (from sapwood to heartwood) in fibre morphological differences in the 9-year old Cedrela wood. We however recommend further studies into the chemical consumption during cooking and other properties of the species for better informed decision on the 9-yr C. odorata, in terms of its use for commercial paper production in Ghana and elsewhere.