Torrance Coste of the Wilderness Committee said consistent budget cuts over the last decade mean park rangers rarely monitor remote sites such as the Carmanah-Walbran Provincial Park, from where the cedar was chopped.
He said that last month, a member of the environmental group became aware of the poached tree and took a photo of about 20 per cent of its remains.
But when Coste went to the park about two weeks ago, more of the cedar had been cut and removed, he said.
"In the first photo, there were two big sections of the trunk beside the stump and when I went up there, there was only one."
He said a stump measuring about three metres in diameter is all that remains of the tree that was dragged across a parking area, where steel cables were left lying around.
"It's an example of how poorly protected our parks are that people can come and take our trees, without fear of repercussions, from our provincial parks."
Coste said 10 full-time park rangers monitor about 1,000 parks and protected areas across British Columbia, down from about 40 full-time positions in 2001.
Don Closson, who supervises the Cowichan area for B.C. Parks, said Parks officials at the site a year ago noticed that about 80 per cent of the tree had been cut through and that a professional faller was hired to bring it down because it posed a safety hazard.
"On our return this year we noticed that somebody had gone in and cut up a large portion of the butt and dragged portions of it into the parking lot," he said.
Blocks of red cedar are valuable as a roofing product, Closson said, adding officials have little information in the case.
"We have no eyewitnesses or licence plates at this time."
RCMP Sgt. Dave Voller of the Cowichan Lake detachment, which is about a two-hour drive from the park, said police are investigating the case of the stolen tree but so far don't have much to go on.
"There's not much we can investigate since we have no physical evidence or description of offenders and once wood is removed from the forest, it's extremely difficult to track where it came from," Voller said.
"That's one of the logistical problems with having a park that's miles from anywhere, with no one who is on site as far as management goes," he said.
One RCMP officer works at the Ditidaht First Nation reserve, about 45 minutes from the park, but doesn't have time to patrol the area, Voller said.
He said whoever took the time to chop down the cedar was likely interested in the valuable return from cedar shakes used for roofing.
"It's obviously much more gain than going out and taking a whole pile of firewood. A logging truck loaded with cedar would be worth thousands and thousands of dollars."
Opposition New Democrat MLA Scott Fraser criticized the Liberal government in the legislature for inadequate protection of the province's parks, saying it's obvious people can chop down old trees without being detected.
"To suggest that anyone is able to protect all of those areas to the level that the member suggests is fiscally irresponsible," said Environment Minister Terry Lake.
"I'll tell you what irresponsible is, 10 years ago there were 194 park rangers in British Columbia, there's under 100 now," Fraser said.