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Day 16 Explain the Anatomy of an Oak Tree

An oak tree

The oak tree is the undisputed king of the Western World. Under optimal conditions oaks can grow to a height of more than 130 feet (40 m) with a dense canopy and live an average of 600 years.

A mature oak tree has a strong trunk with brownish-grey bark. The cross section shows circles of growth rings which record yearly growth of the tree by adding a new layer of wood in each growing season. They reflect the age of the tree and the climatic conditions in which the tree grew. The growing needs nutrition and it relies on a conducting system of xylem and phloem. The xylem carries water and minerals from the roots to the rest of the tree and gives support to the stem or trunk. Outside the xylem is the cambium and the phloem exists between the cambium and bark. In opposite direction, the phloem transports sugar from the leaves to the other parts of the tree. The roots grow sideways to form a deep, broad root system and it is the deep roots support the gigantic trunk.

As deciduous trees, oak trees experience a cycle of leaves blooming and withering with the rhythm of seasons. The leaves are spirally arranged, one leaf to a stem, on alternating sides of the twig. They have rounded lobes on either side of the main vein. The chlorophyll presented in the leaves traps energy from sunlight and uses it to convert water and carbon dioxide into food as all green plants do. Like all fruit-producing trees, oak trees do bloom in the spring. They produce both male and female flowers, which means they self-pollinate. Male flowers are hanging whereas female flowers are hidden among the leaves. Following pollinating, they produce acorns, or oak nuts, which are enclosed in a tough, leathery shell and borne in a cup-shaped cupule with hard pericarp. They also serve as perfect food for many animals like squirrels. In winter, of course, the leaves fall away and the tree is dormant until spring. The blooming ages of oak trees last from around 20 to 80 years old. After that, oak trees stand majestic and towering like a venerable elder with an average life span as long as 600 years.

2017.2.4