甘比拓展写作 the oak tree 张成

The oak tree is the truly king of the Western world. It is known for its lobed leaves and the large cap of its acorn. Under optimal condition oaks can grow to a height of more than 130 feet(40m) and live an average of 600 years.

How the oak grow.

In general, the source of oak's energy is sunlight. The key part for the whole process is chlorophyll. At the very first, the root absorb the water and minerals from ground. The xylem transports water and minerals to the rest of the tree. The leaves absorb CO2 and produce sugars by means of photosynthesis. The essential part for photosynthesis is chlorophyll. The chlorophyll traps energy from sunlight and uses it to convert water and carbon dioxode onto food.  The phloem transports sugars from the leaves to the rest of the tree. In the whole process of transpiretion, the leaves pulls the xylem sap upword. As the oak growth, there are growth rings in trunk. The trunk becomes stronger and stronger and grows straight uoward. The top of the tree widens with branches, which may be twisted, knotted, knotted or bent.

Oak Tree Pollen & Acorns

Oak trees produce both male and female flowers on the tips of their uppermost branches, which are relatively unnoticed. The tree produces hanging male flowers, whereas female flowers are are hidden among the leaves. Pollen from the male flower fertilizes the female ovary, which develops into an acorn. The petals and sepals of the ovary fuse to from the acorn falls off the tree in late summer or early fall, and under the right conditions will germinate and grow into a new oak seeding.