Complex sentence: The tall Norfolk Pine trees had attracted interest by the Royal Navy in the 1770s and the island was originally settled in part to supply timber for masts and spars, so it is ironic that this small ship was the only one built there.
Split into simpler sentences: The tall Norfolk Pine trees had attracted interest by the Royal Navy in the 1770s and the island was originally settled in part to supply timber for masts and spars. So it is ironic that this small ship was the only one built there.