The first slopes of the Andes force the moist, easterly winds to rise, provoking very high condensation leading to the formation of clouds that generate copious amounts of rain. The eastern slopes of the mountains receive between of precipitation a year, although some places receive up to of precipitation annually owing to orographic precipitation. Most of the precipitation is concentrated in the summer, with winters being dry. The high rainfall on these first slopes creates a thick jungle that extends in a narrow strip along these ranges, creating an area of great species diversity. At higher altitudes on these slopes, the climate is cooler and more humid, with the vegetation consisting of deciduous and pine trees.