Dafen of the Yushan National Park (YNP) is a critical habitat for locally endangered Formosan black bears (Ursus thibetanus formosanus). The phenology and acorn production of Cyclobalanopsis glauca potentially influence the temporal and spatial movement, activity and relative abundance of bears and other wildlife. The objective aimed to continue the 8th-year acorn and bear monitoring project. The study was further designed to estimate the population size and genetic variation of the bears and to provide guidelines for conservation and representative data sampling. The 2013 acorn production estimated by the Graves’ modified scale and the 30 second counting method revealed an index of 1.2±1.03 (±SD) and 23.6±35.2 acorn/per tree, respectively. The production of intact and damaged acorns collected and estimated by 195 seed traps were 30 acorns/m2. Based on 166 fecal DNA samples with D-loop sequence successfully amplified, 73 bear individuals were identified during 2009-2012, including 10 individuals revisiting Dafen in different years. According to the clustering analysis with STRUCTURE and Population software, the result showed 3 clusters, but further studies about individual movement and behavior would be helpful. The transect sign survey in mountainous national park, we totally found 22 bear signs in transect. Yushan National park was highest in sign density(6.7 sign/ha, n=16), Shei-Pa National park was second(0.62 sign/ha, n=6).