Looking down from an elevation of 400 kilometres or so, Vancouver Island appears to be covered by a mostly intact jade-green forest from one end to the other. Using a Google Earth mapping tool that incorporates logging data, however, the Sierra Club of B.C. has created a different image – one showing just a few remaining pockets of rich old-growth forest.

"This can be described as an ecological emergency," said Jens Wieting, forest campaigner for the Sierra Club of B.C. "The last big, contiguous old-growth areas with giant trees, such as the Walbran on the southern island and East Creek on the northern island, should be considered as rare as white rhinos."

Just one-tenth of Vancouver Island's most productive old-growth rainforest with the tallest trees remains unlogged, he said, and some of that is currently approved for logging.

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The B.C. government states that on Vancouver Island, 46 percent of the forest on Crown land is still covered by old-growth forest, but Mr. Wieting said that figure is inflated because the province includes less productive ecosystems such as bogs or sparsely treed high elevations. What remains, he said, is a patchwork of forests that are too small to ensure biodiversity.

"For Vancouver Island and British Columbia's south coast, we believe it is urgent to develop a new conservation plan to safeguard the remaining intact areas and to restore older second growth so that we can have some connectivity," he said in an interview.

In February, environmentalists celebrated an agreement to protect the Great Bear Rainforest on B.C.'s central coast. That historic pact ensures that 85 per cent of the old growth will not be logged, includes economic benefits for First Nations and provides the forest industry with a green seal of approval for the timber it is allowed to harvest in the region.

With that agreement completed, environmental campaigns have shifted to other regions. The Sierra Club of B.C. has highlighted logging of old growth just outside the Carmanah Walbran Provincial Park on southern Vancouver Island, and Mr. Wieting said the province should be looking at the objectives of the Great Bear Rainforest there as well.

The province has set aside 1.8 million hectares of old-growth forests on the coast for protection as parks or other conservation areas. Under the Forest and Range Practices Act, it sets targets for old-growth preservation within geographic and biological regions that range from 1 to 28 per cent. It maintains that those parcels are large enough to maintain biodiversity.

However, the independent Forest Practices Board has questioned the government's stance. In a 2012 report, the board said the province has improved its old-growth forest management plans but concluded there is "a compelling need for government to undertake comprehensive effectiveness monitoring to determine whether or not efforts to protect biodiversity in these areas are actually effective."

The provincial Forests Ministry issued a written statement noting it has since pledged to increase tracking and monitoring of old-growth forests.

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Richard Hebda, the Royal B.C. Museum's curator of botany and earth history, said in an interview the Sierra Club's Google Earth mapping tool confirms what his own research has suggested – that there is not much old-growth forest left on Vancouver Island, and that what is left is not well connected.

That is troubling, he said, because B.C.'s intact coastal forests will be crucial in adapting to climate change: "Healthy forests are going to play an important role in our future."

Dr. Hebda said the most resilient forests are those that have been intact for thousands of years, weaving together a complex system of hydrology, soil formation, nutrient cycling and more into an ecosystem that is more capable of surviving changes in climate.

Logging doesn't just remove the trees, he said, but unravels that living fabric that holds those systems together.

"We need a hard-nosed investigation of what we want these forests to be doing: Do we want to protect biodiversity? Do we want them to be very good at storing carbon? Then we can decide how much forest we actually need," he said. "I think the answer will be a much higher percentage than we now have."