From the UC Berkeley newspaper The Daily Californian:
Environmentalists drop clothes at UC Berkeley to protest tree cutting in East Bay hills
Environmentalists shed their clothing Saturday morning on campus to rally against what they see as plans to cut down an estimated 450,000 trees in the East Bay hills.
About 50 people participated in the rally, which took place in the Eucalyptus Grove on the west side of campus and was organized by Jack Gescheidt, founder of the TreeSpirit Project. The project aims to “raise awareness of the critical role trees play in our lives, both globally and personally” through photos of people, often naked, interacting intimately with trees, according to its website.
Little do they realize that the Eucalyptus is an invasive species - FEMA signed off on their removal (PDF file). Fire hazard and the wood is not good for building - more here