I found a nice web site where you can learn about Tundra. But still I took some text from it, and for you.

tundra

Tundra is the coldest of all the biomes. Tundra comes from the Finnish word tunturia, meaning treeless plain. It is noted for its frost-molded landscapes, extremely low temperatures, little precipitation, poor nutrients, and short growing seasons. Dead organic material functions as a nutrient pool. The two major nutrients are nitrogen and phosphorus. Nitrogen is created by biological fixation, and phosphorus is created by precipitation. Tundra is separated into two types: arctic tundra and alpine tundra.

The characteristics of Tundra are:

1. Extremely cold climate
2. Low biotic diversity
3. Simple vegetation structure
4. Limitation of drainage
5. Short season of growth and reproduction
6. Energy and nutrients in the form of dead organic material
7. Large population oscillations

I heard about the Tundra in a talk today. Because the climate is getting warmer, there are more days in the year when the Tundra is too soft for caribou or reindeer [I forget which, or maybe both] to walk on it. I saw a graph of the changes over the years. When the Tundra is frozen, it is easy for the big animals to walk on, but when it melts; their feet will sink into it. I think there are a lot of primitive plants such as moss and lichen growing in the Tundra.