Qianling Mountain Park, in the northwest of the city, is more forest than park. It's a great escape from the crowds and city noise and has some lovely paths up to the Hongfu Temple.
Qianling is known locally as 'monkey park' and you're certain to spot some of its furry inhabitants, not least because many visitors to the park feed them. Note that feeding these supposedly wild macaques is not technically allowed, although no one enforces this rule.