This 63.9 sq km expanse of mixed forest holds one of the largest stands of ancient red hinoki cypress trees left in Taiwan. The most ancient of the ancients is over 2800 years old. A 3.7km boardwalk trail winds through the dense forest via a couple of dozen cypresses, with signs indicating the age, species, height and diameter of each giant.
The visitable area of the reserve is small, and you'll see everything within two hours. To make a day (or two) of it, hikers can take on the 18km Fu-Ba National Trail, which starts (or finishes) in the reserve itself.
You'll need your own vehicle to get here, unless you're prepared to catch a (very) slow bus from Taoyuan train station to Lalashan entrance (route 5301 leaves at 6:30am, route 5090 at 6:47am, both taking around four hours).