The weather during the winter is cold, but when snow melts in the spring, some parts of the forest become swamps. There are not many different types of trees in coniferous forests because of the cold weather, and the poor soil. Fallen branches, needles, and dead animals do not decay as fast as in warmer regions. This is why the soil in coniferous forests is not very fertile. Also, only those trees that have adapted to cold weather and poor soil can survive. These trees have flexible branches that support heavy snowfalls. Less water evaporates from their leaves because of the shape of their needles.