HOUSTON -- As a protest against the construction of the southern route of the Keystone XL oil pipeline enters its fourth week today, the company that it's aimed at may be moving to work around it.

Eight protesters remained camped in tree houses they built in a canopy along the route where TransCanada Corp. controls the right of way for the pipeline's construction. The protest camp began in late September, and its organizer, the Tar Sands Blockade, says the group has enough water and food to last it for several more weeks.

Last week, the group was joined by another protester who began his own "tree sit," climbing into a tree in the path of the pipeline construction to prevent crews from continuing their work. TransCanada confirmed that it is facing another tree protester on its easement.

But David Dodson, a spokesman at TransCanada in Houston managing the company's communications on the Keystone XL work, said neither the tree camp nor other protest actions are slowing work down.

Rather than wait out the tree protest, TransCanada has decided to simply move work around it, Dodson said.

"We went around them," he said. "We have a construction right of way through that property."

Nevertheless, various acts of civil disobedience against the line's construction -- including activists chaining themselves to equipment and attempts at physically blocking work -- are gaining media and celebrity attention. The actress Daryl Hannah, known for her environmental activism, has joined the campaign and was arrested for trespassing after refusing police orders to move out of the path of ground-clearing equipment.

Through subcontractors, TransCanada is employing off-duty police officers to maintain security at the construction sites, Dodson confirmed. Ron Seifert, a leader in the Tar Sands Blockade movement, accuses these officers of overstepping their legal authority, threatening activists with arrests for trespassing even when, according to Seifert's group, they have permission from the legal landowner to be there.

"This is illegal. This pipeline easement is supposed to be no different than a phone line, power line, water line, et cetera," Seifert said. "Can you imagine the phone company threatening to arrest a landowner for trespassing around a phone pedestal sticking up in someone's backyard? It's an egregious overreach."

Dodson declined to speculate on local law enforcement's reasoning behind such actions. TransCanada maintains that the rules governing easements restrict even the landowner from the easement zone while construction is under way.

Protesters are also crying foul over police restrictions on media access to the tree campsite on land just outside of Winnsboro, Texas.

Last week, The New York Times said that two of its reporters were briefly detained by police and escorted off land where they were attempting to report on the ongoing tree protest. Activists are also protesting the apparent arrest of two freelance journalists last week at around the time the Times reporters were detained.

"They detained the two journalists from a major media outlet that wishes to remain anonymous at this time, for several minutes before releasing them," Tar Sands Blockade said on its website. "While they had them in handcuffs TransCanada's hired thugs made a phone call, presumably to higher ups, and then released them."

The newest events are just the latest in a string of incidents pitting the protest movement against TransCanada in their dispute over the controversial project.

On Oct. 1, protest organizers announced that one of their members had locked himself to "a concrete capsule buried directly in the proposed path of the toxic pipeline." Others have been arrested after chaining themselves to construction equipment, and protest members on the ground have been confronted by law enforcement for attempting to keep construction crews away from the tree protest or otherwise trying to block work on the line.

The Houston refining community is eager to see the southern stretch of Keystone XL completed to alleviate a bottleneck of crude oil supplies at Cushing, Okla., storage terminals caused by the growth in U.S. onshore oil production. Dodson estimates that the first section, from Cushing to Houston, should come online by the end of 2013.

Opponents say the line eventually will carry crude derived from Canada's oil sands projects, which they say carries a greater risk of spills and pollution. Seifert said his group has vowed to continue their tree vigil and other actions against the company's work on Keystone XL.

"The blockaders have all the requisite gear to survive through cold weather and rain, as well as weeks of food and water," he said. "The greatest obstacles to the longevity of the tree blockade are the isolation and psychological stress resulting from TransCanada's 24-hour surveillance, policing and floodlights."

Dodson insisted that the company's chief concern is the group's safety but that the tree protest won't prevent work from proceeding now that TransCanada has rerouted the pipeline around them.

"They're not holding anything up," he said.