Whatever the systematic position of the ban tak giant trees they are typical for a much wetter climate than that which prevails today in northern Thailand. The ban tak fossil tree demonstrate that humid evergreen forest was still present at the end of the early pleistocene at about 800 ka (middle pleistocene transition)just before the onset of the very long phase of intensifued climatic oscillations which lasted until ca 10 ka (louys and turner2012) this conclusion is of great importance for the interpretation of the rich pleistocene mammalian faunas of the interpretation of the rich pleistocene mammalian faunas of Thailand the evolution of which was strongly con ditioned by the vegetation (tougard and montuire 2006) the contemporaneous archaic pebble tool assemblages found north of tak which have been interpreted as reflecting the continuance of the humid tropical forest since the Pliocene (hutterer1977) disprove that the subtropical primeval rainforest formed an im penetrable ecological barrier between the northern Chinese population of homo erectus and a southern one in Indonesia as hypothesized by ciichon and Betti's(2009)