Wood Anatomy

Wood is a plant structural tissue. Wood anatomy is porous and fibrous. Wood is found in the stems and roots of various plants. Wood is also a naturally occurring material and wood anatomy is made up of cellulose. The cellulose fibres are very strong and can withstand high levels of tension. Other than cellulose, wood also consists of a chemical known as lignin that allows it to withstand compression. The anatomy of the wood is important because it provides support to the plant, which allows the plant to grow large. It also helps transport nutrients from the root to the leaves.

Cellular Structure of Wood

The behaviour of wood and the material required for its preservation can be decided by studying the wood anatomy and the physical structure of the wood. Wood is porous and is three-dimensional. It is a hygroscopic substance that is connected by cellulose, hemicellulose, and lignin. In other words, it can be described as a bundle of different vessels. These vessels are also used to transport nutrients from the roots to the leaves and also help in the removal of waste material. The formation of wood occurs when cells grow around the plant in the form of rings just within the bark. Wood anatomy is characterised by its several rings that grow in the form of concentric circles. The stem is composed of numerous cells arranged together. These cells are considered the basic unit of the plant. These cells also possess an outer cell wall that is made up of cellulose and covers an internal cellular cavity. The cells of the wood are longer and not so wide since they are arranged along the longitudinal axis of the plant. 

Classification of Wood

Wood can be divided into two major categories depending on their botanical classification. These categories are softwood and hardwood. Softwood is the form of wood that is derived from conifers and gymnosperms. Hardwood is the type of wood that is derived from angiosperms. The classification of wood does not indicate the hardness or the softness of the wood but rather the presence or absence of pores in the cellular structure of the wood. Hardwood also consists of vessels that perform the function of transporting the plant sap in the upward direction. These vessels are a series of large cells arranged linearly and have open ends. When a piece of wood is observed under the microscope, these vessels can be seen as holes or pores. The size and location of these pores can vary from species to species, but they stay relatively constant amongst the same species. Since hardwoods possess large amounts of these vessels, they are often called porous wood. On the other hand, since softwood does not possess a lot of vessels, they are often known as non-porous wood. Since there is a considerable physical and structural difference between softwood and hardwood, it is easier for them to be distinguished under the microscope.

Wood Anatomy

Below the bark of a tree, a thin layer of cells is present that is not visible to the naked eye. This layer of cells is known as the cambium. In this part of the wood anatomy, the cells divide and convert into bark cells. This type of wood anatomy that is newly formed consists of several living cells and is used to transfer sap in the plant. Sapwood is the light-coloured outer portion of a tree trunk through which the water passes from the roots to the leaves and in which excess food is often stored. Eventually, this sapwood matures and is converted to heartwood. Heartwood is the central core of the trunk. This chemical substance also makes the wood susceptible to an early form of decay. The centre of the trunk is called the pith, and it is the part of the tree from where the growth of the wood takes place. The newly formed wood is seen in twigs. 

Conclusion

Hence, it can be concluded that wood is a dead tissue that is present in various plants. Wood is used to provide the plant with structural support, and it also helps transport nutrition from one place in the plant to another. Wood is a naturally occurring substance made up of cellulose, hemicellulose, and lignin. Wood can further be divided into two categories depending on the presence of vessels in them. These vessels appear like holes and hence give a wood a porous appearance. The wood that has vessels is known as hardwood, and the type of wood that does not possess these vessels is called softwood.