The overview of the tree above contains many components to it. The bark of the tree is made up of xylem, phloem, cambium, heartwood, and much more. All these components combine together to make up the bark of this cut down tree. Of these components, xylem plays a very important role. Xylem is commonly referred to as one of the two types of transportation tissues throughout plants in general. The other transportation tissue would be phloem. Xylem tissue and phloem tissue make up the vascular tissue of vascular plants. The basic function of xylem is to transport water throughout the plant. However, xylem also transports some nutrients throughout the plant as well. Xylem is usually made of two types of mechanisms, tracheids and vessel elements. Xylem in the bark of trees is usually separated into two categories, secondary xylem and primary xylem. Secondary xylem grows outward after the vascular cambium has formed. Primary xylem grows with the procambium. All in all, xylem plays an important role in the transportation of nutrients throughout plants.