To commemorate Earth Day 2016, the ASU Wrigley Institute partnered with the City of Tempe to host a clean-up of "A" Mountain on April 22. Roughly 150 volunteers from at least seven organizations hit the trails of Tempe's only preserve, armed with trash pickers and bags. Staff from the Department of Public Works – who had come in on their day off, in some instances – hauled away four dump trucks of debris, with many more small loads taken away in golf carts. According to Robert Bartelme of the City of Tempe, up to 150 bags of trash were removed. This is a testament to the impressive volunteer turnout – the largest in the event's seven-year history.