Most of British Columbia's old-growth forests of big trees live only on maps, and what's left is quickly disappearing, scientists have found.

A report revealed the amount of old-growth forest still standing in the province has been overestimated by more than 20% and most of what's left is at risk of being logged within the next 12 years.

The scientists reported that most of the forest counted as old growth by the province is actually small alpine or boggy forest. Less than 1% of the forest left in the province is composed of the productive ground growing massive old trees, some more than 1,000 years old.

While the authors agree with the official tally that 23% of the forest is old growth, "that is incredibly misleading," said ecologist Rachel Holt.

Change is in the works, but won't be immediate, said Doug Donaldson, minister of Forests, Land, Natural Resource Operations, and Rural Development. "We agree that more work needs to be done."

At stake are more than big trees. Orca whales also rub on beaches downstream and adjacent to some of the forests being cut. Salmon are the primary food source for the northern and southern resident populations of orca whales. Salmon depend on cool, clean water in the streams where they spawn and rear, streams that wind through forests to saltwater where hungry orcas hunt.

"Salmon connect the land to the sea," said Andrew Trites, director of the Marine Mammal Research Unit at the University of British Columbia's Vancouver campus. "How we treat and take care of our forests ultimately determines the fate of our salmon populations."

Old-growth forests also shelter a vast suite of terrestrial life. Insects that live nowhere else thrive in the worlds within worlds of old-growth canopies. Bears den in the cavities of massive gnarly old trees, and birds, including pileated woodpeckers, nest and feed in their branches. Inland rainforests host lichen that are a primary food of mountain caribou, now pushed to the brink of extinction by loss of the forests they depend on. Old-growth forest and forests in general are under assault around the globe as climate change cranks up both the assaults on big trees, and the need to preserve them.