The bridge across Munday Brook is thought to be the oldest
surviving all-wood bridge in Australia.
The Journal of Main Roads Dept of Western Australia had this to say
in an October 1998 article:
"Western Australian bridges have demonstrated the
strength and longevity of wandoo and jarrah hardwood timbers.
...
For the restoration of the Munday Brook bridge at Orange Grove, for
example, it is planned to use a high-pressure water jet for the
first time to remove serious decay from critical timber areas and
to reinstate those areas with structural epoxy
filler."
Once you've admired the bridge, look for a durable piece of
man-made rubbish and an ammo tin underneath it.