In the North, which in the main developed separately from the rest of
the country until the close of the 19th century, monastery doors were
further elaborated by what was called a sum: as carved pediment fixed
directly over the entrance, right against the fa�ade. Because of the
abundance of teak in the northern forests, wood in Chiang Mai and the
surrounding valley s was very much the dominant medium of construction.
The North also produced large numbers of wood carvers. One can see in
these pediments, which serve no structural purpose at all, an
unrestrained display of skill.