**1. Introduction**

Oil palm tree is one of the perennial oil crops that generate economic growth in Malaysia. It belongs in the species *Elaeis guineensis* under *Palmacea* family that comes from the tropical forests of West Africa. Palm oil production has almost doubled in the past decade. It is produced in 42 countries around the world at about 27 million hectares [1]. Oil palm cultivation has also become the first fruits of the world in terms of production for nearly 20 years.

Currently, Malaysia is the regional leader in biodiesel production with an output of 540 million liters per annum as of 2009 [2]. Meanwhile, Indonesia is second with the production of 400 million liters in 2010 [3]. During the process of replanting in Malaysia, large quantities of oil palm trunks (OPT) and oil palm fronds (OPF) waste are produced in oil palm plantations. The trunks are normally left in the field without any utilization thereafter. They are usually cut into pieces and burnt down to avoid insect and incidences [4].

Oil palm trunks have such special characteristics as high moisture content (1.5 to 2.5 times the weight of the dry matter), low cellulose and lignin content and high content of water soluble and NaOH soluble in comparison with rubberwood and bagasse. Physical properties of trunks showed heterogeneity and varied depending on both radial and vertical directions. Some difficulties in utilizing oil palm trunks also lie in extremely tough outer bark and high content of decay able parenchyma cells [5].

From the previous study [1, 6], found that the sugar content in the sap of felled palm trunks increased during storage after logging. This suggests that oil palm trunk can be a promising source of sugar as proper treatment after logging. Sap analysis can be an efficient raw material for bioethanol [6, 7]. In addition, oil palm trunk was considered as a useful material for pulp and paper properties which have been studied [5, 8, 9]. However, the physical, morphological properties and chemical compositions of individual cell of oil palm trunk such as parenchyma and vascular bundle have not been well studied [10].

The aim of this study therefore was to examine the chemical composition of parenchyma and vascular bundle of oil palm trunk that were separated based on storage time [11]. Fibers useful for materials occur in vascular bundle, while living cells containing sugars and starch useful for energy and livestock foods mainly exists in parenchyma. The outcome of this study forms the basis in realization of the full potential of the chemical compositions and it can guide us for particular applications and uses.
