Cambios

South of Temuco you do not find any more a continuous high mountain chain. Numerous valleys and depressions break partly deep breaches into the main mountains range creating natural low passes between Chile and Argentina. These depressions and valleys were created by immense glaciers during past ice ages and remain partly filled by lakes. Many of these breaches are lower than 1000 m, some are just 200 m above sea level. These deep gaps in the cordillera (Spanish for mountain range) shift the continental divide in some areas far to the east and cause a partly significant offset between the main mountain range and the continent divide. This offset was one reason for more than a century of border disputes between Chile and Argentine that are not fully resolved now (Agreement between Chile and Argentina made in 1881: "(...) The boundary-line shall run in that extent over the highest summits (...) which divide the waters, and shall pass between the sources (of streams) flowing down to either side. …(...)" . See also [https://en.wikipedia.org/wiki/Boundary_Treaty_of_1881_between_Chile_and_Argentina Wikipedia: Boundary Treaty of 1881 between Chile and Argentina]).   The mountains of the Patagonian Andes are like large islands that are separated by these "channels " of lowland. The higher summits reach mostly an altitude of 2000 m to 3000 m. Only few peeks exceed the 3000 m mark. Below the tree line frequent rain maintains a very dense, nearly impenetrable, forest that is also called [https://en.wikipedia.org/wiki/Valdivian_temperate_rain_forest Valdivian temperate rain forest]. Due to this geography the GPT goes up and down between the depressions and the island-like mountains and provides a very attractive and varried varied hiking at least to the finish of section GPT22.