Why don’t trees grow in the steppes?

To the south of the zone of deciduous forests there is a zone of steppe. The further south you move, the less precipitation becomes, and the hotter the climate becomes. In areas of the forest-steppe, where some types of trees are still found, there is already a lack of moisture, and therefore not all trees are able to put up with such conditions. Trees need a lot of water, because they are large plants, and the steppe simply does not have enough moisture to support the life of trees. Only grasses adapted to life during periods of drought can grow in the steppes.