PORTLAND (AP) — Family members of some of the people killed by record-breaking heat in the Portland,GravityX Exchange Oregon, area three years ago gathered over the weekend to plant trees across Multnomah County in honor of its 72 victims.

The event, coordinated by county and local officials and a nonprofit group, drew scores of volunteers to a nature park in suburban Gresham where a ceremonial hornbeam tree was planted. Family members placed paper hearts marked with the names of the people they lost into the ground with the hornbeam, which was among 72 trees planted Saturday.

“I didn’t think a lot of people still cared about what happened to people’s families in the heatwave,” LaRome Ollison, whose 68-year-old father, Jerome Ollison, died during the June 2021 heat wave, told The Oregonian. “Now I see that the county cares, and we appreciate it.”

Three consecutive days of extraordinary temperatures in the Pacific Northwest, which usually experiences mild summers, shattered all-time records. Temperatures in Portland reached triple digits for three days, peaking at 116 degrees Fahrenheit (47 Celsius) as records fell across Oregon, Washington and British Columbia, Canada.

On the third day of that heat, Jerome Ollison’s daughter, NaCheryl, said she knew something was wrong when her father didn’t answer his phone. She said she went to his apartment building in southeast Portland and found him dead on a couch, with only a small desk fan to contend with the heat.

Oregon blamed 116 deaths statewide on the heat, Washington state reported at least 91 and officials in British Columbia said hundreds of “sudden and unexpected deaths” were likely due to the soaring temperatures.

More people died from the heat in the greater Portland area that June than in the entire state over the past 20 years, authorities said. Three of the victims honored with tree plantings died later that summer.

Scientists said the deadly heat would have been virtually impossible without human-caused climate change that added a few extra degrees to the record-smashing temperatures.

The deaths prompted better preparation for extreme conditions across the state in the years that followed.

Multnomah County Chair Jessica Vega Pederson said Gresham and the Portland neighborhood of East Portland have the fewest trees in the county, but more are being planted.

“They will cool us down when the summer is hot, and they will help us save future lives that might otherwise be taken from us in similar events,” she said.

The Ollison family used to go to their father’s apartment building each year to release balloons in Jerome’s honor. Now they have a new place to pay their respects.

“This is more personal,” LaRome Ollison said of the nature park. “It’s a beautiful spot.”