There are three types of tundra: Arctic tundra, Antarctic tundra, and alpine tundra. In all of these types, the plants are mostly grass, moss, and lichens. Trees grow in some of the tundra. The boundary between the tundra and the forest is known as the tree line or timberline.The area itself encircles the Arctic Ocean of the Northern Hemisphere. The climate in a tundra biome consists of freezing cold and dryness in the winter and cold summers. The tundra ground is a barren place, often covered with rocks.