How Trees Grow
Just like humans, trees need to breathe to survive. Respiration converts glucose and oxygen into carbon dioxide and water. In a tree, glucose (a form of energy) is created by a process called photosynthesis. Glucose is stored as starch, and this energy will allow the tree to respire and grow.
Photosynthesis occurs in the leaves, turning carbon dioxide and water into glucose and oxygen. There are a range of factors for photosynthesis to be successful which include the correct amount of sunlight, water, nutrients, the optimum temperature, and chlorophyll. In addition, trees only photosynthesise during the day in the growing season (spring and summer months), so it is important that trees generate enough energy for the whole year.
The structure of a tree trunk includes heartwood, xylem cells, phloem cells, the cambium layer, and bark. The xylem cells are responsible for transporting water and nutrients needed for photosynthesis from the roots to the leaves. The phloem cells are responsible for transporting the energy produced in photosynthesis from the leaves to the rest of the tree in a process called translocation.
The growing season of a tree occurs in the spring and summer months, in which there are two main forms of growth. The first is primary growth, which occurs in the tips of the roots and branches, and secondary growth is when a tree grows in width. During winter, trees remain dormant waiting for the temperatures to warm up so they can start growing again.