Estonia has over 1,400 lakes. Most are very small, with the largest, Lake Peipus, being ; it is the fifth largest lake in Europe, and also the largest trans-boundary lake in the whole continent. There are many rivers in the country. The longest of them are Võhandu (), Pärnu (), and Põltsamaa (). Estonia has numerous fens and bogs. Forest land covers 50% of Estonia. The most common tree species are pine, spruce and birch.