If you want it to be ES then read ALL the ES books you can find - The Imperial Library is good for that
Otherwise you will not know where people have made mistakes in their descriptions - as happens to all
Elsweyr has an area in the north that is desert - but it does not cover the whole of the north - and the Tenmar forest in the south is said to be tropical (so was Cyrodiil's said to be
) - but ask yourself what there is in between - in Big Cat country? I suspect Savannah
Valenwood is NOT
FULL of moving trees. There is one species of GIANT trees that move/d ... the Graht Oaks and they migrated north to south. However the 'king of these' - the City Tree Falinesti - and once if not still capital of Valenwood is rumoured to have ceased to walk ...
you see you need the detail to make it work ... happy reading ^^