Guardian: Lisa Kellman of the Environmental Sciences Research Center at St. Francis Xavier University, Canada, and her team have been investigating the impact that forest harvesting has on the underlying soil. It seems that the damage goes deeper than previously thought and lasts for much longer than traditionally assumed. When we buy a new wardrobe made from sustainably sourced wood, we tend to assume that the trees that were harvested to make the product were replaced by new trees, which continue to mop…