1. Trunk is the main vertical supporting structure of trees. ? Trunk refers to the main vertical supporting structure of the whole tree, usually located between the root and crown. It is the main part of trees and plays an important role in supporting, transporting water and nutrients and storing energy. Trunks are usually made of cellulose and lignin, which makes them strong and elastic. The outside of the stem is usually called bark, while the inside includes the woody part of the trunk.

2. The trunk is the woody part in the stem. ? Trunk is the wooden part inside the trunk, which is the main mechanical support and transportation system of trees. Trunk includes heartwood and sapwood of wood parts. Heartwood is usually located in the center of the trunk. This is the oldest and strongest part, and usually has a dark appearance. The sapwood is located on the periphery of heartwood, which is relatively young and usually lighter in color. One of the main functions of the trunk is to transport water and nutrients, which rise to the crown through the wooden part of the trunk and distribute to all parts of the whole tree.

3. There are obvious differences between trunk and trunk in structure. The trunk is usually located at the root, and the trunk extends to the crown. The trunk is the main visible part of the tree, and the trunk is usually wrapped under the bark, which is not easy to see directly. Therefore, the trunk is mainly composed of wood tissue, and the trunk includes the whole visible part of the tree, including trunk, branches and leaves.

Trunk and trunk have different functions. ? Trunk is the main mechanical support of trees, which can resist wind and external pressure and maintain the stability of trees. It also undertakes the task of transporting water and nutrients to ensure the growth and maintenance of trees. On the other hand, the trunk is the main visible part of the tree, which expands the volume of the tree through growth and branching, and is also an important place for photosynthesis, which absorbs sunlight through leaves and converts it into energy.

The shape and appearance of trunks and stems are also different. ? Trunk usually has a thick appearance, and its surface may be full of texture and bark texture. The appearance of the trunk varies with the tree species. Some trunks may be smooth and uniform, while others may have potholes and uneven surfaces. On the contrary, the trunk is usually the whole visible part of the tree, including the trunk, branches and leaves. Its appearance depends on the type and growth conditions of trees, and it can take on various shapes and colors.