There was a dead tree in 2012 but there wasn't when I've been to there this summer.
Beetle. It had a tendency to drop immediately when disturbed. Fortunately, unlike some weevils, its bright coloration made it actually feasible to find the beetle again on the ground.
蓬萊細矮吉丁蟲 Nalanda formosana
Possible Dicerca divaricata. Ovipositing on a dead Red Elm tree