The Hammonds, father and son, had been serving five-year federal prison sentences and will be immediately released.
The Hammonds were convicted in 2012.
"We brought it to the attention of the vice president, " said David Duquette, a Hermiston resident who serves as national strategic planner for the advocacy group Protect the Harvest.
Jamie Rappaport Clark, president of the group Defenders of Wildlife, noted that the Hammonds were convicted of arson, a serious crime.
The pardons are the latest in a growing list of clemency actions by Trump. Several convoys of supporters from central OR and elsewhere were planning to converge in Burns to greet the Hammonds.
Federal prosecutors painted sinister portraits of the Hammonds at their trial.
Prosecutors say the Hammonds set the fires to cover up their illegal deer poaching. "Jurors were told that Steven Hammond handed out "Strike Anywhere" matches with instructions that they be lit and dropped on the ground because they were going to 'light up the whole country on fire.' One witness testified that he barely escaped the eight to ten foot high flames caused by the arson".
"All of those who went with us and supported the Hammonds", he said, "they should be pardoned also". They were found guilty by a jury and faced mandatory sentences of five years. Trump blamed the Obama administration for filing an "overzealous appeal" because the judge's sentence was too lenient under federal sentencing guidelines.
Dwight Hammond, 76, has served three years in prison. However, in October 2015, a federal appeals court ordered them to be resentenced to the mandatory minimum.
An armed militia group occupied the headquarters of the Malheur National Wildlife Refuge from January 2, 2016 to February 11, 2016 to protest federal land management, and the leaders of that occupation said they were trying to bring attention to the Hammonds' ordeal. Another key occupier, Robert "LaVoy" Finicum, was fatally shot that day by Oregon State Police.
Not everyone in Burns was in support of the Hammonds returning, KOIN reports. The two paid $400,000 to the Bureau of Land Management to settle a related civil suit. He declined further comment Wednesday. They changed the name of the refuge to Harney County Resource Center, reflecting their belief that the federal government has only a limited right to own property within a state.
The arrest of the two men sparked rancher Ammon Bundy to launch an armed standoff in 2016.
Militants who occupied the Malheur National Refuge and previously confronted federal agents at the Cliven Bundy ranch in Nevada will also see the Trump administration as sympathetic to their aims, he said.
The OFB, which has advocated on the Hammonds' behalf, said on Tuesday that their punishment was a case of "prosecutorial overreach and bureaucratic vendetta".
"Obviously, when we get some good news like the pardoning of the Hammonds to start our day it makes everything just a little bit better around here after a couple of year of working on this tough issue", said Ethan Lane, Executive Director of the Public Lands Council and NCBA Federal Lands.