Bukit Lima Forest Park is Sibu's easiest patch of urban forest, a boardwalk-and-trail escape from traffic and concrete. It protects peat-swamp forest on the edge of town, with birds, insects, and the damp green stillness that makes Borneo feel close even in an ordinary city.
Do not expect wilderness. Come for a morning walk, bring water, and wear shoes that can handle mud if it has rained. It is a good antidote to the hard surfaces of central Sibu.