Oregonian: Tree death rates are rising in established old-growth forests across the West, scientists say. This shot is from the Gifford Pinchot National Forest. A small increase in temperatures during the past three decades probably contributed to a doubling of tree death rates in undisturbed old-growth forests across the West, a team of researchers reported in the journal Science today, with the increase in mortality highest in the Pacific Northwest. The researchers ruled out insect …