So, there are a lot of beavers in Tierra Del Fuego.  According to Uwe, there were 30 mating pairs brought here for fur in the mid 1900's.  There are now over 65,000 beavers here, and not many trees.  65,000 beavers can seriously mess up an ecosystem, and a hiking trail, for that matter.  Slogging through beaver wreckage is not fun.  Beavers are not our friends.