Casuarina equisetifolia (木麻黃)
This sometimes massive tree certainly lives up to its name. It is one tough tree that can cope with almost all Hong Kong conditions.
At the USRC it is tall and could be mistaken for a pine tree because it bears needle-like branchlets. Its leaves are minute (a few mm in length) and sit as mere scales around the nodes of thin, ribbed, needle-like, green branchlets. Such structures; tiny leaves and needle-thin branchlets, help to conserve water. It has extremely hard wood. Interestingly, it has separate male and female flowers (most plants have both sexes integrated within the same flower). In addition, the flowers are small with minimum decoration.
Fauna you may find here: