FORT BENTON, Mont. — An activist who was trying to call attention to climate change was found guilty of criminal charges on Wednesday for closing a valve last year on a pipeline carrying crude oil from Canada to the United States.

A Montana jury found Leonard Higgins of Portland, Oregon, guilty of criminal mischief and trespassing.

Higgins could face up to 10 years in prison and a $50,000 fine on the felony criminal mischief charge. Trespassing is a misdemeanor with a penalty of up to six months in county jail and a $500 fine.

A sentencing hearing is scheduled for Jan. 2. Court officials initially said Higgins would be sentenced Wednesday.

In a written statement, Higgins said he planned to appeal.

Higgins entered a fenced site near Big Sandy, Montana, in October 2016 and closed a valve on pipeline operated by Spectra Energy. The pipeline carries oil from Canada's tar sands region.

Activists simultaneously targeted other pipelines in Washington state, North Dakota and Minnesota.

The protesters called pipeline companies ahead of time to warn about their actions, and workers shut down four of the sites before protesters reached the valves. The pipeline targeted in Washington state was not operating at the time.

Spectra Energy is now owned by Enbridge Inc. of Calgary, Alberta. Spokesman Michael Barnes did not immediately return a telephone message seeking comment.

The company previously condemned the protests as "dangerous and reckless."

Higgins, 65, a retired technology worker for the state of Oregon, said before the trial he wanted to present a "necessity defense" and argue that his act of civil disobedience was necessary because climate change is an emergency that cannot be ignored.

But District Judge Daniel Boucher (boo-SHAY) said in an April order that testimony on climate change would be irrelevant to the charges. Boucher said he would not allow the trial to be used as a vehicle for political protest.

"I was disappointed and surprised by the verdict, but even more disappointed that I was not allowed a 'necessity defense,' and that I wasn't allowed to talk about climate change as it related to my state of mind," Higgins said Wednesday.

A Minnesota judge will allow two activists to use the necessity defense when they go on trial on Dec. 11 for a similar protest.

Emily Johnston and Annette Klapstein are charged with felony counts of criminal damage to critical public service facilities and other counts after closing valves on two pipelines in northwestern Minnesota. Both are from the Seattle area.

Michael Foster of Seattle was convicted of criminal mischief, conspiracy to commit criminal mischief and trespass on Oct. 6 after closing the valve on the Keystone pipeline in North Dakota. His judge barred him from using a necessity defense.

Foster could face up to 21 years in prison at his Jan. 18 sentencing.