Joseph Knowland State Arboretum and Park

Some of the natural highlights of the park include rare native plant communities, thriving but threatened wildlife, choice bird-watching locales, and a known-critical migratory corridor for mountain lions and bobcats.

The park is traversed along its northern boundary by Arroyo Viejo which flows to Lion Creek and then San Leandro Bay.

[4] In 2010, the East Bay Chapter of the California Native Plant Society (EBCNPS) included Knowland Park in its South Oakland Botanical Priority Protection Area due to its rich native plant resources that include rare natural communities of Valley Needlegrass Grassland and Maritime Chaparral.

[6] On December 9, 2014, the Oakland City Council voted to block public access to dozens of acres within the heart of the park by granting a mitigation easement to offset the damage that would occur from a planned development by the Oakland Zoo onto the western highland of Knowland Park.

The Save Knowland Park Coalition, which includes the Sierra Club - East Bay Chapter, California Native Plant Society, California Grasslands Association, several other environmental organizations as well as the Green Party are supporting a referendum effort to put the issue to a vote of Oakland registered voters.