Trees have seven stages of development, similar to those found in human growth and development. These stages are infancy, youth, prime of life, middle-age, senior, twilight and death, says The Arbor Day Foundation.
In the infancy and youth stages, trees are most vulnerable to the environment. Trees in these stages need nurturing so that they make the necessary adjustments to their surroundings, similar to small children. The limbs are thin, small and these trees have pointy tops.
In the prime of life, trees have round tops and a full crown, along with strong branches. Pruning low, dead branches may be the only necessary maintenance for the tree to grow and bear fruit. The terrain may need thinning in forests, so that the trees have extra room to grow and expand without obstruction. In the middle-age stage, trees provide optimum shade. The limbs are thicker and the crown flattens.
Major limbs deteriorate in the senior stage of tree life. Flat canopies and heavy limbs develop, but pruning dead limbs form gaps in the canopy. Small crowns with scattered twigs accompany the twilight stage, which may last up to 50 years. The integrity of the base slowly deteriorates until reaching the final stage, death.