Under the wooden ceiling of the John W. Olver Design Building, constituents, colleagues and friends of former Rep. John Olver gathered on Sunday to celebrate the life and legacy of the University of Massachusetts professor-turned-public servant.

Olver passed away in late February after representing the Amherst community for 43 years, serving as a state representative, state senator and congressman until his final term ended in 2012. Olver pursued public office after teaching chemistry at UMass for eight years, a portion of his career which U.S. Sen. Elizabeth Warren said defined the former congressman’s unique approach to lawmaking.

“John answered the call to public service with the curiosity of an educator, with the precision of a scientist and with the integrity of the man that he was,” Warren said in a video message. “He was as comfortable in the Capitol as he was in the classroom or on a farm.”

Warren recalled having “long conversations” about transportation with Olver, who led the creation of the John W. Olver Transit Center in Franklin County, the nation’s first net-zero transit facility.

U.S. Rep. Jim McGovern remembered Olver for his dedication to the environment and recounted hiking Mt. Holyoke in Hadley with Olver and a group of reporters after the city was redistricted from Olver to McGovern’s constituency.

“John was commenting on everything, telling us about the moss, the trees, the rock formations, the birds and the bugs,” McGovern said. When Olver got ahead of the pack and let out a strange noise, McGovern recalled thinking the former congressman had suffered a heart attack, only to find him marveling at an unusual scene in nature.

“He said, ‘Could that be sassafras growing at this height?’” McGovern said, met with laughter from the crowd. “He was unique, but most importantly, he was effective… He used his position on the Appropriations Committee to make sure that the funding was there for everything that was important to him.”

McGovern noted Olver mentored a new generation of public servants, including State Rep. Natalie Blais and former Northampton Mayor David Narkewicz, who served on his congressional and district staff.

“The people that he attracted, that he brought into public service, were the best of the best,” McGovern said.

McGovern’s district director Jon Niedzielski was one of many former Olver staffers who attended the service, crediting the former congressman for sounding the alarm on climate change before it was a topic of national discussion.

“He had a way of sort of seeing the forest through the trees,” Niedzielski said after the service. “He knew that sometimes it takes a long time to get people to accept an idea — climate change was one of those. John was talking about this way back in the early ‘90s, even before.”

Olver was instrumental in the development of the UMass design building, which the University prides as the nation’s “largest and most technologically advanced academic contemporary wood structure.”

“There is no other project that better personifies John’s commitment to the environment, his love of science and planning and his desire to bring people together for the greater good,” UMass Chancellor Kumble Subbaswamy said in a statement following Olver’s passing.

Architects intended for the building to have a steel frame, but Olver helped convince the University to create a wood structure that exemplified the latest in green building technology. He went on to secure partial funding from the state legislature for the building project to demonstrate the impact of mass timber on the region.

“When [students] come in here, and they see this vaulted ceiling, and we see the trees on the roof, somebody had to have had that idea and been the person who said, ‘You really have to do this,’” Niedzielski said. “John was that kind of person.”

Sophie Hauck can be reached at [email protected] and followed on Twitter @SophieBHauck.