sentences:  The lower reaches of Guadarrama Mountain Range are populated by species such as the "Juniperus thurifera", the maritime pine, the Portuguese oak, the stone pine; only in the somewhat more humid westernmost end of the region, near the , there are forests of chestnut tree.54,4% of the surface of the region is soil categorised as forest areas of which the 51.4% (27.7 % of the total of the region) it is already covered by forests, so there is room for tree re-population.The first modest efforts towards tree re-population were taken in the Lozoya Valley in the late 19th century intending to achieve a purer water from the river, that provided the capital with water for consumption.