Pashtuns were worshipping a giant tree in mid 12th century ?

As late as the mid-12th century, some Pashtuns might not yet converted to Islam, or they were Muslims but still had retained some of the pre-Islamic practices. According to the "Ajaib al-Makhluqat" of Muhammad al-Tusi (written in 1160-1167 AD), there was a large tree with circumference of seventeen arsh (?) in a Tamarisk forest of the Pashtun country. That particular tree was known as 'the tree of Brahman' (درخت برهمن) and Pashtuns would prostrate before it.