VICTORIA – Researchers collected DNA from the tops of some of Canada’s tallest trees to search for mutations that could provide evidence of how the ancient forest giants evolve to survive. It involved ascending 20 Sitka spruce trees on Vancouver Island, averaging 80 metres tall and ranging in age from 220 years to 500 years old, to reveal that the old-growth trees developed mutations to their genetic code as they grow and age. Prof. Sally Aitken, associate dean in the faculty of forestry at the University of British Columbia, said they wanted to know whether mutations that occur during growth, as opposed to those during reproduction, could add up to substantial changes for the trees. …The research is the first evidence of the large amount of genetic variation that can accumulate in the trees over centuries, she said. Scientists have long known about mutation growth over time, but little about its frequency and contribution to genetic variation, Aitken added.